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J.  F.  MECKEL, 

It 

Professor  of  Anatomy  at  Halle,  &c.  ice.  &c. 

TRANSLATED  FROM  THE  GERMAN  INTO  FRENCH, 
WITH  ADDITIONS  AND  NOTES, 

BY 

A.  J.  L.  JOURDAN, 

Member  of  the  Royal  Academy  of  Medicine  at  Paris,  &c.  &c.  &c. 


G.  BRESCHET, 

Adjunct  Professor  of  Anatomy  at  the  School  of  Medicine,  &c.  &c.  &c. 
TRANSLATED  FROM  THE  FRENCH, 
WITH  NOTES, 

BY  A.  SIDNEY  DOANE,  A.  M„  M.  D. 


IN  THREE  VOLUMES. 
VOLUME  III. 


PHILADELPHIA: 

CAREY  & LEA— CHESTNUT  STREET. 

1832. 


\ Y i eate-L  u 
V.  3 

I 2 3 3u 


Institut« 


11  Entered,  according  to  act  of  Congress,  in  the  year  1832,  by  Henry  C.  Sleight,  in  the 
office  of  the  Clerk  of  the  District  Court  of  the  Southern  District  of  New  York  ” 


SLEIGHT  AND  ROBINSON,  PRINTERS, 

No.  Ill  Nassau  St.,  New- York. 


MANUAL 


OF 

GENERAL,  DESCRIPTIVE,  AND  PATHOLOGICAL 

ANATOMY. 


DESCRIPTIVE  ANATOMY. 


SECTION  II. 


OF  THE  PERIPHERY  OF  THE  NERVOUS  SYSTEM. 

§ 1809.  The  periphery  of  the  nervous  system,  comprehending  the 
nerves  properly  so  called,  is  divided  into  three  sections  : the  nerves  of 
the  spinal  marrow  or  the  spinal  nerves,  the  nerves  of  the  brain  or  the  en- 
cephalic nerves,  and  the  ganglionnary  or  great  sympathetic  nerve.  The 
number  of  these  nerves,  including  the  last,  is  forty-three  pairs.  But 
anatomists  do  not  divide  them  in  the  same  manner,  for  several  cerebral 
nerves  have  been  blended  which  are  now  considered  as  distinct  pairs  ; 
and  farther,  some  consider  as  cerebral  nerves  those  which  others  refer 
to  the  spinal  pairs. 

We  shall  point  out  the  differences  arising  from  the  first  of  these 
sources  in  our  general  remarks  on  the  cerebral  nerves.  Those  which 
arise  from  the  second  depend  principally  upon  the  division  of  the 
central  mass  of  the  nervous  system.  If  the  medulla  oblongata  be 
considered  as  the  summit  of  the  spinal  marrow,  we  must  naturally 
arrange  the  nerves  arising  from  it  among  the  spinal  pairs  ; hence  their 
number  is  increased,  while  that  of  the  cerebral  pairs  is  diminished. 

Vol.  III.  2 


6 


DESCRIPTIVE  ANATOMY. 


Thus  Gordon  admits  only  eight  pairs  of  cerebral  nerves  and  thirty- 
four  pairs  of  spinal  nerves.  Bichat  makes  three  classes,  the  first  com- 
prising two  nerves  of  the  cerebrum,  the  second  six  of  the  mesoce- 
phalon,  and  the  third  thirty-four  spinal  nerves.  Others  with  Portal, 
tacitly  admit  another  intermediate  class  in  which  the  accessory  nerve 
is  placed,  which  in  the  geneial  method  belongs  to  that  of  the  cerebral 
nerves.  Others  as  Sabatier,  Bichat,  and  Cloquet,  following  Willis, 
exclude  the  first  nerves  of  the  spinal  marrow  from  the  number  of  spinal 
pairs,  and  consider  them  as  the  most  inferior  cerebral  nerves. 

This  last  method  is  the  least  natural  of  all,  for  although  the  upper 
pair  of  the  spinal  nerves  is  often  between  the  cerebral  and  spinal  nerves 
in  character,  as  may  be  seen  from  the  description,  still  it  is  more  like 
the  latter  than  the  former.  The  want  of  exactness  in  considering  the 
last  four  cerebral  nerves  as  the  first  spinal  pairs,  is  also  proved  by  the  con- 
tradiction between  the  general  characters  of  these  four  nerves  and  those 
of  the  spinal  marrow,  and  it  then  becomes  impossible  to  generalize 
about  these  last.  This  classification  is  farther  very  inconvenient,  since 
a slight  examination  demonstrates  that  certain  nerves  (for  instance,  the 
auditory  and  external  motor  nerves)  arise  from  the  same  region  of  the 
central  part  of  the  nervous  system  ; and  with  a little  care  and  patience 
this  may  be  proved  of  most  of  the  others.  The  same  reasons  which  im- 
pelled us  to  separate  the  medulla  oblongata  from  the  spinal  marrow,  and 
to  consider  it  as  a portion  of  the  encephalon,  have  obliged  us  to  place 
the  nerves  derived  from  it  among  the  cerebral.  The  characters  of  these 
nerves,  which  resemble  those  of  the  cerebral  rather  than  those  of  the 
spinal  nerves,  demonstrate  also  the  superiority  of  our  method. 

We  shall  first  examine  the  spinal  nerves,  not  only  because  we  have 
already  treated  of  the  spinal  marrow  when  describing  the  cervical  part 
of  the  nervous  system,  but  because  from  the  cerebral  nerves,  which 
will  be  mentioned  last,  we  shall  naturally  pass  to  the  organs  of  sense, 
and  from  them  to  the  more  complex  organs,  with  which  we  shall' close 
the  treatise. 


CHAPTER  I. 

NERVES  OF  THE  SPINAL  MARROW. 

§ 1810.  We  have  already  mentioned  the  general  characters  of  the 
nerves  of  the  spinal  marrow  :(1)  they  are  divided  into  as  many  sec- 
tions as  there  are  regions  in  the  vertebral  column,  consequently  into 
cervical , thoracic , lumbar , and  sacral  nerves. 

We  shall  first  describe  the  thoracic  nerves,  except  the  first  one, 
because  they  are  more  simple  and  arise  the  first  ; next  the  nerves  of 
the  limbs,  those  of  the  inferior  extremities  arising  from  most  of  the 

(1)  J.  J.  Huber,  Dc  medulla  spinali,  speeialim  de  nervis  ab  cil  provenienlibufi) 
Gottingen,  1741. — G.  Frotscher,  De  medullâ  spinali  cj usrjue  nervis,  Erlange»,  1786. 


* 


OF  THE  NERVOUS  SYSTEM. 


1 


sacral  and  lumbar  nerves,  those  of  the  superior  from  the  first  dorsal 
and  the  last  four  cervical  ; finally,  the  four  superior  cervical  nerves, 
which  lead  by  a remarkable  transition  to  the  cerebral  nerves. 

Before  describing  minutely  the  nerves  of  these  different  regions,  we 
ought  to  make  known  the  following  characters  which  belong  to  them 
in  common,  and  which  are  important  in  regard  to  their  topography. 

1st.  There  is  no  constant  difference  between  the  nerves  of  the  right 
and  those  of  the  left  sides. 

2d.  The  nerves  are  not  perfectly  symmetrical  ; one  is  often  situated 
higher  than  another,  and  the  number  of  cords  is  frequently  greater  by 
two  or  three  on  one  side  than  on  the  other.  But  this  difference  is 
almost  always  compensated  for,  because  then  the  adjacent  pairs  vary 
in  the  opposite  manner. 

3d.  The  upper  and  lower  pairs  are  much  nearer  each  other  than  the 
central.  The  latter  also  after  the  last  dorsal  nerve,  are  so  near  each 
other  that  they  do  not  seem  like  separate  nerves.  They  are  also  much 
nearer  in  the  early  periods  of  existence,  and  even  during  the  first  years 
of  life,  than  at  subsequent  periods.  This  propinquity  in  the  superior 
and  inferior  regions,  is  owing  to  the  disproportion  between  the  size  of 
the  nerves  and  the  shortness  of  that  part  of  the  spinal  marrow  from 
whence  they  arise.  Hence  why  the  smaller  thoracic  nerves,  which 
arise  not  much  above  the  place  from  whence  they  leave  the  spinal 
marrow,  are  farther  from  each  other,  and  the  reason  of  the  greater 
distance  between  the  spinal  nerves  in  animals  whose  necks  are  longer, 
and  in  whom  too  the  spinal  marrow  descends  lower  than  in  man. 

4th.  The  ganglions  formed  by  the  posterior  roots  are  situated  in  the 
intervertebral  foramina,  except  those  of  the  sacral  nerves  which  are 
found  in  the  cavity  of  the  sacrum. 

These  ganglions  are  not  all  of  the  same  size  in  all  regions,  and  their 
development  is  not  in  a direct  ratio  with  that  of  the  nerves.  In  fact,  a 
ganglion  which  is  usually  large,  is  not  unfrequently  replaced  by  another 
very  small,  and  vice  versa.  The  ganglions  of  the  dorsal  nerves  are 
generally  the  largest,  and  those  of  the  sacral  nerves,  especially  the 
last,  the  smallest. 

5th.  All  the  spinal  nerves  divide  soon  after  coming  from  the  verte- 
bral column  into  two  branches,  an  anterior  and  a posterior,  the  first  of 
which  is  often  larger  than  the  other,  excepting  always  those  of  the 
second  cervical  nerve,  which  presents  a contrary  arrangement.  The 
anterior  branches  turn  first  outward,  then  forward  and  inward,  and 
terminate  near  or  upon  the  anterior  median  line.  The  posterior  go 
directly  backward,  and  are  distributed  to  the  muscles  which  fill  the 
groove  between  the  spinous  and  transverse  processes  of  the  vertebra?, 
or  in  those  which  correspond  to  them  in  the  cranium  and  the  skin  of 
this  region.  The  first  are  distributed  to  the  anterior  muscles,  which 
represent  these  dorsal  muscles  on  the  sides  and  anteriorly,  and  in  those 
of  the  extremities. 


8 


DESCRIPTIVE  ANATOMY. 


6th.  All  the  spinal  nerves  communicate  together  very  constantly  by 
one  or  several  larger  or  smaller  branches  which  they  give  off  soon 
after  leaving  the  vertebral  canal,  and  which  anastomose  with  those 
analogous. 

The  anastomosing  branches  usually  arise  from  the  anterior  part  of 
the  nerves,  or  belong  only  to  their  anterior  branches,  and  go  before  the 
transverse  processes  on  the  sides  of  the  bodies  of  the  vertebræ.  The 
brachial,  lumbar,  and  sacral  plexuses,  are  formed  entirely  in  this  man- 
ner ; their  arrangement,  however,  differs  from  that  usually  seen,  being 
more  complex,  since  the  anastomosing  branches  produce  others  winch 
anastomose  several  times  with  those  near.  Nerves  composed  of  fila- 
ments from  several  trunks  of  different  origins,  arise  from  these  points  of 
union  whether  single  or  multiple. 

One  or  more  anastomosing  branches  communicate  at  the  same  time 
with  the  branches  of  the  ganglionnary  system  in  the  limiting  gan- 
glions. 

Besides  these  anterior  anastomosing  branches  which  form  along  the 
vertebral  column,  a series  of  plexuses,  corresponding  in  number  to  that 
of  the  vertebræ,  the  posterior  branches  also  anastomose  in  an  ana  logous 
manner,  especially  at  the  upper  region  of  the  neck,  although  this  ar- 
rangement is  less  general  posteriorly  than  anteriorly. 


§ 1811.  The  dorsal,  thoracic,  costal,  or  intercostal  nerves  (JV.  tho 
racici,  s.  dorsales , s.  costales , s.  intercostales)  are  like  the  dorsal  ver- 
tebræ, twelve  in  number.  Some  anatomists,  however,  as  Haller,(l) 
count  only  eleven,  and  annex  to  the  lumbar  nerves  that  usually  re- 
garded as  the  twelfth.  We  shall  examine  only  the  eleven  inferior 
nerves,  as  it  is  more  convenient  to  describe  the  first  with  the  four 
inferior  cervical  nerves. 

The  general  characters  of  these  nerves  are  as  follow  : 


1st.  They  make  part  of  the  smaller  nerves  of  the  spinal  marrow, 
and  are  particularly  smaller  than  the  inferior  cervical,  the  lumbar,  and 
the  superior  sacral  nerves. 

2d.  Most  of  them,  especially  the  inferior,  are  those  spinal  nerves 
which  arise  farthest  from  each  other.  Still  the  superior  are  nearer 
to  each  other  than  the  superior  cervical  nerves  are. 

3d.  Most  of  them  communicate  only  by  intermediate  filaments  in 
the  vertebral  canal.  Still  we  have  often  found  between  the  first  and 
second  pairs,  as  between  the  second  and  third,  a filament,  proceeding 
obliquely  from  above  downward,  and  from  within  outward,  from  the  su- 


ARTICLE  FIRST. 


DORSAL  NERVES. 


(1)  El.phys.,  lib.  x.  not.  38. 


OF  THE  NERVOUS  SYSTEM, 


perior  edge  of  the  inferior  nerve  to  the  inferior  edge  of  the  nerve  situated 
immediately  above.  They  have  always  seemed  smaller  between  the 
second  and  third  pair  than  between  the  first  and  second. 

4th.  Their  trunk  furnishes  on  emerging,  and  immediately  after,  some 
thin  short  branches  which  go  forward  and  enter  either  into  the  nearest 
limiting  ganglion  of  the  ganglionnary  nerve,  or  more  rarely  into  the  fila- 
ment of  communication  between  two  of  these  adjacent  ganglions.  It 
then  divides  soon  after  emerging  into  two  branches,  one  anterior , inter- 
costal, or  subcostal  (R.  intercostalis,  s.  subcostalis ),  the  other  posterior 
or  dorsal  ( R . dorsalis ). 

The  anterior  branch  proceeds  under  the  rib,  below  which  the  trunk 
comes  from  the  vertebral  canal,  between  the  external  and  internal 
intercostales  muscles,  and  advances  as  far  as  these  last  extend.  It 
accompanies  the  intercostal  vessels  lodged  more  or  less  immediately 
in  the  groove  of  the  rib.  In  its  course  it  gradually  leaves  the  superior 
rib,  so  that  its  anterior  part  is  nearer  the  rib  below  than  that  above.  It 
then  perforates  the  intercostales  muscles  near  the  sternum,  and  be- 
comes external.  Proceeding,  it  gives  branches  to  these  muscles,  the 
upper  part  of  the  abdominal  muscles,  and  to  the  skin  which  covers  the 
intercostales  muscles.  These  last  filaments  called  the  external  thoracic 
nerves  {R.  pectorales  externi ),  successively  perforate  the  intercostales 
muscles  from  behind  forward,  but  all  arise  very  far  from  the  place 
where  they  emerge. 

Each  anterior  branch  near  its  origin,  sends  off  posteriorly  several 
branches,  of  which  the  internal  are  usually  numerous,  and  go,  inde- 
pendently of  those  coming  from  the  trunk,  to  the  limiting  ganglions  of 
the  ganglionnary  nerve  and  their  filaments  of  union,  and  anastomose 
in  this  place  with  the  analogous  branches  of  the  adjacent  dorsal  nerves, 
while  the  external  which  are  simple,  pass  on  the  internal  face  of  the 
ribs,  and  communicate  with  those  of  the  two  adjacent  dorsal  nerves 
which  go  to  meet  them.  These  last  are  sometimes  deficient  in  the 
middle  pairs  : but  then  absence  is  not  always  observed,  as  they  not 
unfrequently  occur  there,  although  they  are  more  developed  in  the 
upper  and  lower  pairs. 

The  posterior  branch  proceeds  backward  between  the  transverse 
processes  of  the  vertebrae,  between  which  it  arises  under  the  multifidus 
spinæ  muscle,  and  there  usually  divides  into  external  and  internal 
branches,  the  latter  of  which  are  smaller  and  are  deficient  when  the 
division  does  not  take  place. 

The  internal  branches  are  distributed  to  the  multifidus  spinæ,  the 
semispinalis,  the  spinalis,  the  internal  belly  of  the  sacro-lumbalis,  the 
digastricus  nuchæ,  the  complexi,  the  transversalis,  the  inferior  portion 
of  the  splenius,  the  rhomboidei,  the  trapezius,  and  the  latissimus 
dorsi  muscles. 

The  external  branches  proceed  outwardly,  emerge  between  the 
scalenus  muscle  and  the  internal  belly  of  the  sacro-spinalis,  and  in  this 
place  penetrate  between  the  two  bellies  of  the  latter  muscle,  to  which 
they  are  distributed  and  also  to  the  superficial  muscles  of  the  back. 


ÏO 


DESCRIPTIVE  ANATOMY. 


Besides,  these  two  branches  usually,  but  not  always,  extend  to  the 
skin. 

All  the  dorsal  nerves  are  not  of  the  same  size.  Except  the  first, 
which  is  the  largest,  they  go  on  increasing  in  size  much  from  the 
second  to  the  last.  However,  they  do  not  enlarge  uniformly  ; Haller(l) 
and  Sœmmerring  have  observed,  and  the  results  of  our  numerous  dis- 
sections also  coincide  with  their  opinion,  that  the  the  fourth,  sixth,  and 
eighth,  are  smaller  than  the  fifth,  seventh,  and  ninth. 

§ 1812.  The  differences  in  the  distribution  of  the  thoracic  nerves, 
depend  principally  on  their  anterior  or  intercostal  branches. 

The  first  is  remarkably  distinguished  from  the  others.  It  soon  goes 
upward  and  outward  above  the  first  rib,  toward  the  brachial  plexus, 
and  opposite  to  this  rib  divides  into  two  branches.  One  which  is  pro- 
portionally very  small,  goes  forward  and  proceeds  below  the  first  rib 
like  the  anterior  branches  of  the  other  thoracic  nerves..  The  second 
is  much  larger,  and  ascends  and  corresponds  to  the  small  anastomosing 
branches  of  the  other  thoracic  nerves  ; it  immediately  unites  with  the 
brachial  plexus,  with  which  we  shall  describe  its  farther  progress. 

The  anterior  branches  of  the  second  and  third'  thoracic  nerve,  to- 
gether furnish  to  the  skin  of  the  arm  an  inferior  branch,  which  may 
be  called  the  brachial  nerve.  Both  then  send  some  filaments  to  the 
intercostales  muscles,  penetrate  the  external,  then  descend  to  the  in- 
teguments at  the  axilla  and  unite,  but  not  always  uniformly,  with 
the  internal  cutaneous  nerve  of  the  arm,  and  expand  in  the  superior 
and  internal  part  of  the  integuments  of  the  arm,  so  that  their  filaments, 
especially  those  of  the  second  pair,  descend  to  the  elbow. 

Anteriorly,  the  anterior  branches  of  these  two  nerves  terminate  in  the 
anterior  part  of  the  pectoralis  major  and  the  triangularis  sternqmuscle. 
In  their  passage  they  furnish  no  constant  branches  to  the  abdominal 
muscles. 

The  anterior  extremities  of  the  anterior  branches,  and  of  the 
second,  third,  fourth,  fifth,  sixth,  and  seventh  thoracic  nerves,  are 
distributed  also  in  these  two  muscles,  the  skin  of  this  region,  and 
the  thymus  gland.  The  external  pectoral  twigs  of  these  branches 
penetrate  Into  the  upper  part  of  the  obliquus  externus  and  rectus  ab- 
dominis muscles,  also  in  the  skin  which  covers  them. 

The  anterior  extremities  of  the  anterior  branches  of  the  eighth, 
ninth,  tenth,  and  eleventh  thoracic  pairs,  pass  above  the  costal  digi- 
tations of  the  diaphragm,  glide  between  the  obliquus  internus  and 
transversalis  abdominis  muscles,  distribute  filaments  to  these  muscles, 
and  then  go  to  the  posterior  face  of  the  rectus  muscle  and  to  the  skin 
which  covers  it. 

The  external  pectoral  twigs  of  these  branches  are  distributed  in 
the  upper  part  of  the  obliquus  abdominis  internus  muscle  and  the  skin 
near  it. 


(1)  Depart,  c urp.  hum.,  vol.  viii.  p.  399. 


OF  THE  NERVOUS  SYSTEM. 


II 


The  eleventh  thoracic  nerve  gives  filaments  to  the  posterior  part  of 
the  diaphragm. 

The  twelfth,  described  by  Haller  as  the  first  lumbar  nerve,  anasto- 
moses by  a large  branch  with  the  first  lumbar  pair,  and  sends  filaments 
to  the  diaphragm,  then  passes  before  the  superior  part  of  the  quadratus 
lumborum  muscle,  between  it  and  the  posterior  tendon  of  the  transver- 
salis,  gives  off  filaments  and  divides  at  its  external  edge  into  superficial 
and  deep  abdominal  branches.  The  former  pass  between  the  trans- 
versalis  and  obliquus  internus  abdominis  muscles,  and  terminate  there, 
and  also  in  the  lower  part  of  the  rectus  and  pyramidalis  muscles.  The 
second  go  between  the  two  oblique  muscles,  pass  through  the  external, 
and  are  distributed  to  the  integuments  of  the  abdomen  as  far  as  the 
ossa  ilia. 


ARTICLE  SECOND. 

LUMBAR  AND  SACRAL  NERVES. 

§1813.  The  description  of  the  lumbar  and  sacral(\ ) nerves  ought 
to  follow  that  of  the  thoracic,  because  by  then  describing  the  cervical, 
we  proceed  from  below  upward  to  the  explanation  of  the  encephalic 
nerves.  We  shall  combine  our  observations  in  regard  to  these  two 
orders  of  spinal  nerves,  because  they  resemble  each  other  in  their  most 
essential  characters,  and  particularly  as  they  unite  to  form  the  nerves 
of  the  inferior  extremities. 

The  five  lumbar  nerves  and  the  sacral  nerves,  which  are  also  five 
and  sometimes  six  in  number,  arise  near  each  other  from  the  inferior 
prominence  of  the  spinal  marrow.  They  emerge  from  the  medullary 
canal,  the  lumbar  passing  out  through  the  intervertebral  foramina, 
situated  between  the  lumbar  vertebrae  as  between  the  last  one  and  the 
upper  surface  of  the  sacrum.  The  sacral  nerves  form  the  sacral 
foramina,  except  the  last,  which  passes  between  the  sacrum  and  the 
first  piece  of  the  coccyx.  Not  only  the  anterior  and  posterior  roots  of 
each  pair,  but  the  different  pairs  themselves  are  closely  united  to  each 
other  from  their  origin  to  the  ganglions  formed  by  their  posterior 
branches  ; but  neither  the  first  nor  second  communicate  by  inter- 
mediate filaments.  The  sacral  nerves  differ  from  all  other  spinal 
nerves  by  the  situation  of  their  ganglions,  which  do  not  anastomose 
when  coming  from  the  nerve,  but  in  the  channel  of  the  vertebral 
column,  and  are  as  much  more  distant  from  the  sacral  foramina  the 
lower  the  origins  of  the  nerves  to  which  they  belong,  so  that  the  an- 
terior and  posterior  roots  of  these  last  unite  even  within  the  medullary 
canal.  The  trunks  resulting  from  their  union  divide  near  their  origin, 
and  also  within  the  vertebral  canal,  into  anterior  and  posterior  branches, 

(1)  J.L.  Fischer,  Descriptio  anatomica  nervorum  himbalium,  sacralium  el  cxtre- 
mitalum  infer iorum,  Leipsic,  1791. 


12 


UESCKXI'TIVE  ANATOMY. 


which  do  not  usually  anastomose  together  in  this  canal,  hut  emerge, 
the  first  through  the  anterior  sacral  foramina,  the  others  through  the 
posterior  sacral  foramina.  The  union  of  the  anterior  and  posterior 
roots  of  the  sacral  nerves  in  the  medullary  canal,  undoubtedly  corres- 
ponds to  the  fusion  of  the  false  sacral  vertebræ  in  a single  bone,  and 
it  takes  place  after  the  same  type  so  evident  in  the  vascular  system. 
Perhaps,  also,  it  partially  depends  on  the  greater  distance  between  the 
point  from  whence  the  nerves  originate,  and  that  whence  they  emerge. 
One  circumstance  favors  this  conjecture,  viz.  that  the  place  where  the 
posterior  and  anterior  roots  unite,  is  farther  in  the  inferior  nerves  where 
the  trunk  is  proportionally  longer.  But  this  circumstance  also  favors 
the  opinion  first  proposed,  since  the  inferior  false  sacral  vertebrae  unite 
also  sooner  than  the  superior. 

The  anterior  branches  of  these  ten  nerves  which  enlarge  very  much, 
form  a plexus  which  may  be  called  the  femoral  or  crural  plexus  ( plexus 
femoralis).  This  plexus,  like  the  brachial  and  cervical,  is  produced  by 
the  increase  and  multiplication  of  the  anastomoses  between  the  anterior 
branches,  which  is  in  proportion  to  the  increase  of  volume  of  the 
nerves,  and  which  takes  place  in  breadth,  and  from  without  inward, 
and  in  thickness  or  from  behind  forward. 

We  may  consider  separately  the  superior  and  inferior  parts  of  this 
plexus,  the  first  as  the  lumbar  or  lumbo-abdominal(l)  plexus,  the  se- 
cond as  the  sacral  or  sciatic  plexus , since  from  each  of  these  two  parts, 
which  are  formed,  the  first  by  the  lumbar,  the  second  by  the  sacral 
nerves,  arise  nerves  which  are  distributed  differently.  Still  as  the 
principal  nerves  which  come  from  it  are  all  distributed  to  the  lower 
extremities,  it  is  more  convenient  to  regard  them  as  forming  one  plexus 
only,  as  the  inferior  lumbar  nerves  mostly  form  the  sacral  plexus  and 
the  nerves  which  come  from  it. 

This  plexus  is  indicated  in  the  dorsal  region  by  the  much  smaller 
anastomosis  between  the  anterior  branches,  and  which  are  constantly 
developed  in  the  inferior  thoracic  pairs. 

Of  the  nerves  which  form  it,  the  upper  suddenly  enlarge  very  much 
from  above  downward,  and  the  lower  from  below  upward. 

The  last  two  sacral  nerves  are  the  smallest,  and  the  last  es- 
pecially is  the  smallest  of  all  the  spinal  nerves.  Next  comes  the  first 
lumbar,  then  the  third  sacral  ; the  second  lumbar  is  a little  larger, 
being  about  the  same  size  as  the  second  sacral  ; the  third  and  fourth 
lumbar  which  are  almost  equal,  are  a little  larger  than  the  preceding. 
The  fifth  lumbar  and  the  first  sacral  are  much  the  largest. 

Dorsal  branches  which  are  much  smaller  arise  from  all  these  nerves 
which  unite  to  form  the  crural  plexus,  commencing  before  the  union  of 
their  anterior  branches,  when  they  emerge  from  the  foramina  : these 
go  directly  backward  between  the  transverse  processes  of  the  lumbar 
vertebræ  and  the  sacrum,  passing  there  through  the  posterior  sacral 

(1)  J.  A.  Schmidt,  De  plexu  lumbali,  de  nervis  lumbaliqus  corumque  ylexu  com- 
mcntarius  anatomko-patkologicus,  Vienna,  1794. 


OF  THE  NERVOUS  SYSTEM. 


13 


foramina.  These  branches  are  distributed  to  the  posterior  part  of  the 
muscles  of  the  back,  to  the  gluteus  maximus  and  the  skin  which 
covers  them. 

The  posterior  branches,  the  dorsal  or  lumbar  (R.  postici,  s.  dorsales , 
s.  lumbales ),  of  the  lumbar  nerves  diminish  considerably  in  volume  from 
the  first  to  the  last,  so  that  the  last  two  rarely  extend  to  the  skin,  but 
are  distributed  only  in  the  common  belly  of  the  sacro-lumbalis  and 
multifidus  spinæ  muscles.  From  the  first  sacral  nerve  to  the  fourth, 
the  posterior  branches  again  enlarge  much.  That  of  the  fourth  is  the 
largest  ; the  fifth  is  smaller,  while  the  sixth  is  much  more  minute. 

§ 1814.  The  anterior  or  abdominal  branches  {R.  antici,  s.  abdcnni- 
nales ) of  the  lumbar  nerves  pass  behind  the  psoas  magnus  muscle,  unite 
not  only  with  each  other,  but  beside  the  first  with  the  anterior  branch  of 
the  last  dorsal,  the  last  with  the  anterior  branch  of  the  first  sacral,  to 
form  the  lumbar  plexus,  the  lumbar  ganglion  of  the  ganglionnary 
nerve,  and  produce  the  nerves  we  are  about  to  describe.  The  anterior 
branches  of  the  sacral  nerves,  principally  the  first,  second,  third,  and 
fourth,  concur  in  the  same  manner  to  form  the  sacral  plexus  to  which 
the  fifth  contributes  least,  and  the  sixth  takes  no  part  when  it  exists. 

Some  ramifications  arise  from  the  anterior  twigs  after  their  union, 
some  of  which,  the  smaller  ones,  are  usually  formed  by  the  filaments 
of  a single  nerve,  while  others  which  are  larger,  arise  from  the  union  of 
fasciculi  from  several  nerves. 

The  first  are  principally  the  external  pudic  nerve,  several  branches 
for  the  muscles  in  the  lumbar  region,  the  skin  of  this  region  and  the 
common  integuments  of  the  inguinal  region,  the  gluteal  nerves  and  the 
inferior  and  middle  hemorrhoidal  nerves. 

The  second  are  the  three  nerves  of  the  lower-  extremities,  the  obtu- 
rator, the  crural,  and  the  gluteal  nerve. 

A.  SMALL  NERVES  WHICH  ARISE  FROM  THE  ANTERIOR  BRANCHES  OF 
THE  LUMBAR  AND  SACRAL  NERVES. 

§ 1815.  First  and  second  lumbar  nerve.  From  the  first  and  second 
lumbar  nerve,  especially  from  the  inferior  extremity  of  the  plexus  be- 
tween them,  arises  the  external  pudic  or  the  genitocrural  nerve  (N. 
pudendus  externus , s.  spermaticus  externus , s.  inguinalis , s.  genito-cru- 
ralis ),  which  passes  between  the  superior  digitations  of  the  psoas  mus- 
cle,arives  at  the  anterior  face  of  this  muscle,  on  which  it  goesfrom  behind 
forward  and  from  above  downward,  and  divides  within  the  pelvis  into 
branches  which  all  emerge  from  the  inguinal  ring.  Among  these,  the 
most  considerable  which  are  always  the  continuation  of  the  trunk, 
arrive  at  the  spermatic  vessels,  and  are  distributed  in  the  male  in  the 
cremaster  muscle  and  its  coats,  and  in  the  female  in  the  round  liga- 
ment of  the  uterus,  and  anastomosing  with  the  inferior  pudic  nerves, 
terminate  in  the  glands  and  integuments  of  the  inguinal  region.  The 
external  passes  under  the  crural  arch,  penetrates  the  aponeurosis,  is  dis- 

Vol.  III.  3 


14 


DESCRIPTIVE  ANATOMY, 


tributed  in  the  skin  to  the  middle  of  the  internal  face  of  the  thigh,  and 
anastomoses  with  some  filaments  of  the  crural  nerve. 

Besides  there  arise  from  the  first  lumbar  nerve  and  its  anastomosis 
with  the  second,  branches  designed  for  the  psoas,  the  quadratus  lum- 
borum,  and' the  transversalis  abdominis  muscles,  and  for  the  integuments 
of  the  lumbar  and  inguinal  regions.  One  of  these  branches,  which  is 
large,  penetrates  the  psoas  muscle,  goes  forward  between  the  obliquus 
internus  and  transversalis  along  the  crest  of  the  ilium,  and  terminates 
in  the  inferior  part  of  the  large  abdominal  muscles  and  skin  of  this 
region  and  of  the  scrotum. 

Several  filaments  come  from  the  second  lumbar  nerve  and  are 
distributed  to  the  psoas  and  quadratus  lumborum  muscles  and  the  skin 
of  the  lumbar  and  inguinal  regions  : usually  there  arise  one  or  two 
distinct  branches  which  are  longer  {nerfi  lio-scrotal,  Ch.),  which  passing 
through  the  psoas  muscle,  proceed  outwardly  before  the  quadratus 
lumborum,  penetrate  the  transversalis,  then  the  obliquus  internus,  to 
which  they  give  filaments,  go  forward  along  the  crest  of  the  ilium, 
perforate  the  aponeurosis  of  the  obliquus  externus,  and  are  distributed 
to  the  skin  of  the  inguinal  region  and  scrotum. 

3d.  The  third  lumbar  nerve  usually  gives  off  a cutaneous  nerve 
which  unites  to  the  preceding  one  or  replaces  it  either  partially  or 
wholly,  descends  between  the  psoas  and  iliacus  muscles,  emerges  from 
the  pelvis,  passing  under  the  outward  extremity  of  the  crural  arch  and 
is  distributed  to  the  external  and  anterior  extremities  of  the  integuments 
of  the  thigh  to  the  neighborhood  of  the  knee.  There  it  is  the  infe- 
rior branch  of  the  crural  plexus  of  Bichat,  the  inguino-cutané  of 
Chaussier. 

4th.  The  fourth  lumbar  nerve  usually  gives  branches  only  to-  the 
iliacu3  muscle. 

5th.  The  anterior  branches  of  the  fourth  and  fifth  lumbar  nerve  unite 
to  form  a very  considerable  trunk,  the  lombo-sacral  nerve  of  Bichat 
(JV.  lumbo-sacralis ),  which  is  much  larger  than  the  crural,  and  give 
origin  in  the  very  cavity  of  the  small  pelvis,  but  always  before  uniting 
with  the  first  sacral  nerve,  to  the  superior  gluteal  nerve  (JY.  glutæus 
superior ),  which  emerges  from  the  pelvis  below  the  upper  edge  of  the 
sciatic  notch,  is  distributed  to  the  gluteus  médius  and  minimus,  and 
penetrates  even  forward  to  the  tensor  vaginæ  femoris. 

6th.  From  the  second  and  third  sacral  nerve,  come  some  fasciculi 
which  unite,  then  give  filaments  to  the  pyramidalis  muscle,  and  coming 
from  the  pelvis  below  it,  go  to  form  the  inferior  gluteal  nerve. 

Before  these  fasciculi,  a very  considerable  nerve  arises  from  these 
same  nerves  farther  below  and  forward,  sometimes  also  from  the  fourth 
sacral  nerve,  called  the  external  common  hemorrhoidal  nerve  (JY.  pu- 
dendo-hœmorrhoidalis  communis  externus ),  which  re-enters  into  the 
pelvis,  between  the  two  sacro-sciatic  ligaments,  and  divides  into  two 
branches,  the  external  pudic , and  the  inferior  hemorrhoidal  nerve. 

The  external  or  superior  pudic  nerve,  ischio-pénien  or  ischio-clitori- 
dien , Ch.  ( N . pudendus  externus , s.  superior),  goes  along  the  ascending 


OF  THE  NERVOUS  SYSTEM. 


15 


branch  of  the  ischium  and  the  descending  branch  of  the  pubis,  pro- 
ceeding on  gives  branches  to  the  obturator  internus  and  bulbo-caver- 
nosus  muscles,  then  passes  under  the  symphysis  pubis  to  go  forward, 
as  the  dorsal  nerve  of  the  penis  (JY.  dorsalis  penis)  in  the  male,  and 
that  of  the  nerve  of  the  clitoris  (JY.  clitoridcus , s.  pudendus  superior) 
in  the  female,  proceeds  along  the  penis  and  clitoris,  sends  filaments  to 
the  skin  which  covers  them,  and  also  to  the  mons  veneris  and  mucous 
membrane  of  the  urethra,  and  terminates  finally  in  the  glans. 

The  inferior  hemorrhoidal  nerve,  called  also  the  inferior  pudic  (JY. 
hœmorrhoideus,  s.  pudendus  inferior ),  partly  accompanies  the  pre- 
ceding, then  goes  upward  between  the  bulbo-  and  ischio-cavernosus 
muscle,  is  distributed  to  the  integuments  and  in  all  the  muscles  of  the 
perineum  to  the  inferior  extremity  of  the  rectum,  the  skin  of  the  scro- 
tum and  mucous  membrane  of  the  urethra,  and  anastomoses  with  the 
external  pudic,  the  inguinal  and  internal  hemorrhoidal  nerves. 

From  the  difference  in  size  between  the  penis  and  clitoris,  the  external 
pudic  is  the  larger  of  these  two  branches  in  the  male,  while  the  internal 
hemorrhoidal  is  the  larger  in  the  female. 

7th.  The  third  and  the  fourth  sacral  nerves  also  give  off  the  middle 
hemorrhoidal  nerves  (JY.  hcemorrhoidales  medii),  which  are  smaller, 
and  not  united  at  then-  origin  ; but  this  term  is  not  exact  for  they 
are  distributed  partly  to  the  rectum,  the  levator  and  sphincter  ani  mus- 
cles, and  proceed  on  the  side  of  this  intestine  to  be  distributed  from  be- 
low upward  in  the  walls  of  the  bladder,  at  the  commencement  of  the 
urethra,  uterus,  and  vagina,  the  prostate  gland  and  vesiculæ  séminales 
in  the  male,  and  frequently  anastomose  with  the  lower  part  of  the 
great  sympathetic  nerve  to  give  origin  to  the  hypogastric  plexus. 

8th.  The  fifth  and  sixth  lumbar  nerves,  when  they  exist,  are  in  fact 
connected  with  the  crural  plexus,  but  do  not  contribute  to  form  the 
nerves  which  come  from  them.  Their  anterior  branches  are  distributed 
to  the  sacro-coccygeal,  the  levator,  and  sphincter  ani  muscles.  Their 
posterior  are  distributed  in  the  integuments  of  the  posterior  part  of  the 
anus  and  perineum. 


B..  LARGE  NERVES  WHICH  ARISE  FROM  THE  ANTERIOR  BRANCHES  OF 
THE  LUMBAR  AND  SACRAL  NERVES,  OR  NERVES  OF  THE  INFERIOR 
EXTREMITIES. 

I.  OBTURATOR  NERVE. 

§ 1816.  The  obturator  nerve,  sous-pubiofémoral,  Ch.  (JY.  obtura- 
torius),(l)  the  smallest  of  those  belonging  to  this  division,  arises  from 
the  most  anterior  fasciculi  of  the  second,  third,  and  fourth  lumbar  nerves, 
rarely  from  the  first,  by  an  equal  and  sometimes  greater  number  of 

(1)  See  in  regard  to  this  and  the  following  nerve,  M.  C.  Styx,  Descript,  anat. 
nervi  cruralis  et  obturatorii,  Jena  1782. 


16 


DESCRIPTIVE  ANATOMY. 


roots,  which  meet  at  acute  angles.  It  descends  into  the  lower  pelvis, 
before  the  following  nerve,  is  covered  by  the  psoas  muscle,  goes  for- 
ward along  the  linea  innominata,  accompanied  by  the  vessels  of  the 
same  name,  comes  out  through  the  obturator  foramen,  and  divides  into 
two  branches,  an  anterior  superficial  and  large  and  a posterior  deeper 
and  smaller. 

The  anterior  branch  is  distributed  to  the  gracilis,  the  adductorlongus, 
and  brevis  muscles,  and  sends  to  the  internal  saphena  nerve  some 
branches  which  are  sometimes  so  large  that  this  last  seems  to  arise 
from  it  rather  than  from  the  crural. 

The  posterior  branch  is  distributed  in  the  obturator  muscles,  particu- 
larly the  externus,  and  in  the  adductor  magnus  muscle,  even  descend- 
ing to  near  its  inferior  extremity. 

II.  CRUIiAL  NERVE. 

§ 1817.  The  crural  nerve,  férnoro-pré tibial , Ch.  (JY.  cruralis),  is 
larger  than  the  preceding,  behind  which  it  is  situated,  arises  from  the 
posterior  part  of  the  first,  second,  third,  and  fourth  lumbar  nerves, 
descends  along  the  posterior  and  external  side  of  the  crural  artery,  be- 
tween the  psoas  and  iliacus  muscles,  gives  several  branches  to  these 
two  muscles,  but  principally  to  the  second,  and  furnishes  one  conside- 
rable which  sometimes  come  off  higher  than  the  branches  destined 
to  the  iliacus  muscle,  anastomoses  near  the  crural  arch  with  another 
branch  which  arises  in  this  place,  comes  sometimes  also  from  the 
fourth  lumbar  nerve,  and  then  is  distributed  in  the  integuments  of  the 
anterior  and  internal  face  of  the  thigh.  This  branch  is  called  the 
superior  or  the  small  saphena  nerve  (JY.  saphenus  superior , s.  minor). 

A branch  is  generally  given  off  a little  below  the  crural  arch  which 
proceeds  from  within  outward,  and  goes  to  the  common  lower  ex- 
tremity of  the  iliacus  and  psoas  muscles. 

The  nerve  then  divides  generally  below  the  crural  arch  into  two 
branches,  an  external  larger,  and  an  internal  smaller,  above. 

The  external  branch  also  soon  divides  into  several  twigs,  which  go 
to  the  four  heads  of  the  extensor  of  the  leg,  to  the  crurceus,  and  to 
the  tensor  vaginæ  femoris  muscle.  These  branches  descend  to  the 
articulation  of  the  knee  and  penetrate  into  its  capsule. 

The  internal  branch  gives  to  the  sartorius  muscle  many  twigs,  most 
of  which  enter  its  middle  and  inferior  part.  It  gives  them  also  to  the 
skin  of  the  internal  face  of  the  thigh.  But  the  largest  of  all  the 
branches  which  come  from  it  is  the  internal  saphena  nerve,  tibio-cu- 
t ané,  Ch.  (JY.  saphenus  internus ).  This  nerve  accompanies  the  in- 
ternal saphena  vein,  which  it  surrounds  at  several  different  parts, 
distributes  some  filaments  to  the  integuments  of  this  region,  descends 
on  the  back  of  the  foot,  and  extends  even  to  the  great  toe. 


OF  THE  NERVOUS  SYSTEM. 


17 


III.  SCIATIC  NERVE. 

§ 1818.  The  sciatic  nerve,  grand  femoro-poplité,  Ch.  (JY.  ischiadi- 
cus),(  1)  the  largest  of  all  the  nerves,  not  only  of  the  inferior  members, 
but  even  of  the  whole  body,  arises  from  the  inferior  half  of  the  fourth 
lumbar  nerve,  and  from  all  the  fifth,  also  from  the  three  superior  sacral  ; 
the  anterior  branches  unite  to  form  the  sciatic  or  sacral  plexus  ( plexus 
sacralis , s.  ischiadicus ),  which  is  only  the  inferior  part  of  the  crural 
plexus,  although  we  usually  consider  this  the  only  plexus  of  nerves  of 
the  lower  extremities. 

§ 1819.  The  sciatic  nerve  sometimes,  partially  or  wholly,  gives  off 
the  superior  gluteal  nerve  and  always  the  inferior  either  wholly  or 
partially.  This  last  emerges  sometimes  above  and  sometimes  below 
the  pyramidalis  muscle,  anastomoses  with  a branch  of  the  sciatic 
nerve  which  arises  a little  lower,  and  is  distributed  with  it  in  the 
gluteus  maximus  muscle. 

§ 1820.  The  sciatic  nerve  emerges  from  the  sacral  plexus  through 
the  sciatic  notch,  between  the  pyramidalis  and  gemelli  muscles. 

There  it  sends  to  the  obturator  internus  a considerable  branch  which 
penetrates  from  without  inward  between  the  large  and  small  sciatic 
ligaments,  and  enters  from  below  upward  into  this  muscle. 

Then  it  gives  a second,  which  descends  before  the  gemelli  and  the 
tendon  of  the  obturator  internus,  distributes  filaments  to  the  first  two 
of  these  muscles,  and  is  distributed  in  the  quadratus  femoris  muscle. 

Still  lower  a large  branch  leaves  its  posterior  part,  and  unites  to  the 
inferior  gluteal  nerve  (§  1788),  with  which  it  goes  to  the  gluteus 
maximus  muscle. 

The  trunk  first  gives  branches  to  the  flexor  muscles  of  the  thigh  ; 
then  to  the  long  head  of  the  biceps  ; then  to  the  semitendinosus  ; far- 
ther on,  to  the  semimembranosus  muscle  ; finally,  to  the  short  head  of 
the  biceps.  The  filament  of  the  semimembranosus  is  distributed  also 
to  the  adductor  magnus  muscle. 

Farther  on  it  gives  off  the  middle  posterior  cutaneous  nerve  (JY. 
cutaneus  posterior  médius ),  which  descends  under  the  skin  of  the  pos- 
terior face  of  the  thigh  and  leg  to  the  calf,  and  anastomoses  with  some 
filaments  of  the  superior  and  inferior  nerves. 

The  inferior  posterior  cutaneous  nerve  (JY.  cutaneus  posterior  infe- 
rior) is  given  off  below  this  branch  ; it  proceeds  in  part  hke  the  former 
one,  and  is  partially  expanded  hi  the  posterior  part  of  the  capsular  liga- 
ment of  the  knee. 

§ 1821.  The  sciatic  nerve  then  divides  into  two  branches  : the  in- 
ternal, the  larger,  is  the  tibial  nerve,  and  the  external,  the  smaller,  the 
peroneal  nerve.  This  division  usually  takes  place  at  the  middle  of  the 
thigh,  often  higher  up,  and  even  above  the  sciatic  tuberosity,  so  that 
the  two  branches  are  separated  from  each  other  by  the  pyramid- 
alis muscle. 


(1)  J.  H.  Joerdens,  Descriptio  nervi  ischiadici,  Erlangen,  1788. 


18 


DESCRIPTIVE  ANATOMY. 


When  the  bifurcation  occurs  higher  than  usual,  it  is  analogous  to 
the  arrangement  of  the  sciatic  nerve  in  the  mammalia. 

Rosenmuller  mentions  a national  difference  in  regard  to  the  height 
of  this  division,  viz.  that  the  sciatic  nerves  divide  very  high  in  the 
inhabitants  of  the  north  of  Europe,  while  in  those  of  the  south  it  bifur- 
cates very  low  not  far  from  the  ham.(l)  We  have  not  observed  this 
difference. 

When  the  nerve  divides  high,  the  two  branches  are  separated  by  the 
pyramidalis  muscle,  and  they  descend,  the  external  behind,  the  internal 
before  it. 

The  popliteal  nerve  (JV.  popliteus ) rarely  or  never  exists. (2)  At 
most  the  name  of  the  internal  and  the  external  popliteal  nerve  may  be 
given  to  the  upper  part  of  the  two  terminating  branches  of  the  sciatic 
nerve,  from  their  origin  to  the  femoro-tibial  articulation. 

a.  Peroneal  nerve. 

§ 1822.  The  peroneal  or  external  popliteal  nerve  (JV.  peroneus ) often 
gives  origin  to  the  posterior,  inferior,  and  middle  cutaneous  nerves.  It 
descends  from  within  outward  on  the  internal  side  of  the  biceps  femo- 
ris  muscle,  passes  between  the  extensor  longus  digitorum  communis 
and  peroneus  longus  muscles,  sends  filaments  to  these  muscles,  and 
likewise  to  the  tibialis  anticus,  and  divides  very  high  up  into  two 
branches,  the  superficial  and  the  deep  peroneal  nerves. 

§ 1823.  The  superficial  peroneal , or  the  muscular  cutaneous  nerve, 
prétibio-digital , Ch.  (JV.  peroneus  superficialis ),  soon  divides  into  two 
branches,  an  external  superficial  and  small,  the  other  internal,  which 
is  deeper  and  larger. 

The  first,  or  the  cutaneous  peroneal  nerve,  which  might  more  pro- 
perly be  called  the  middle  cutaneous  nerve  of  the  back  of  the  foot , or  the 
external  branch  of  the  peroneal  nerve  (JV.  cutaneus  peroneus , s.  cuta- 
neus  médius  dorsi  pedis,  s.  cutaneus  peroneus  externus ),  descends  on  the 
peroneus  brevis  muscle,  passes  on  the  crucial  ligaments  of  the  tarsus, 
is  distributed  to  the  skin  of  the  external  part  of  the  back  of  the  foot,  and 
terminates  by  filaments  which  are  the  tibial  nerve  of  the  little  toe,  the 
dorsal  nerves  of  the  fourth  toe,  and  the  peroneal  nerve  of  the  third  toe. 

The  second,  the  anterior  nerve  of  the  back  of  the  foot  (JV.  dorsi  pedis 
anticus  communis,  s.  peroneus  anticus,  s.  pedalis  anticus),  is  situated 
before  the  former,  also  near  the  surface,  and  is  distributed  partly  to  the 
internal  half  of  the  back  of  the  foot,  partly  to  the  skin  of  the  external 
and  anterior  faces  of  the  leg,  and  terminates  by  producing'  the  dorsal 
nerves  of  the  two  external  toes  and  the  peroneal  nerve  of  the  third. 

§ 1824.  The  deep  peroneal  or  anterior  tibial  nerve,  prélibio-sus-plan- 
iaire , Ch.  (JV.  peroneus  profundus ),  descends  deeply  between  the 

(1)  In  Neer  Journal  der  Erfindungen  in  der  Natur-und  Arzneywissenschqft,  part 

ii.,  p.  100. 

(2)  Coopmans  has  made  the  remark  (Neurol.,  ed.  2,  p.  198. 


OF  THE  NERVOUS  SYSTEM. 


19 


muscles  on  the  anterior  face  of  the  tibia,  at  the  side  of  the  anterioi 
tibial  artery,  but  does  not  pass  with  it  from  the  posterior  to  the  anterior 
face  of  the  leg,  between  the  two  bones,  for  the  whole  trunk  of  the 
peroneal  nerve  is  situated  and  divides  on  the  external  face  of  the  fibula. 

Such  at  least  is  always  the  arrangement  of  the  deep  peroneal 
nerve  according  to  our  observations.  Although  we  have  made  many 
careful  dissections,  yet  we  have  never  seen  it  pursue  the  course  of  the 
anterior  tibial  artery.  Thus,  although  this  authority  is  sanctioned  by 
a great  name,(l)  it  certainly  is  not  the  usual  arrangement,  and  should 
be  considered  as  a very  rare  anomaly,  more  especially  as  many 
writers,  Coopmans(2)  among  others,  do  not  sanction  it,  or  speak  only 
of  the  first. 

This  nerve  gives  filaments  to  the  peroneus  longus,  and  to  the 
extensor  longus  digitorum  communis  muscle,  to  the  tibialis  anticus, 
and  to  the  extensor  hallucis  proprius,  passes  under  the  crucial  liga- 
ment of  the  tarsus,  and  arrives  on  the  back  of  the  foot,  where  it  termi- 
nates in  the  extensor  digitorum  brevis,  the  first  interosseous  muscle,  and 
the  internal  part  of  the  skin  of  this  region,  by  anastomosing  with  some 
branches  ofthe  cutaneous  nerve  around  the  foot,  so  that  the  dorsal  nerves 
of  the  large  toe  more  properly  arise  from  this  than  from  the  latter. 

We  have  always  found  the  peroneal  nerve  distributed  in  this  man- 
ner, but  we  have  never  found  that  of  the  two  branches  into  which  it 
divides  at  the  upper  extremity  of  the  fibula,  one  was  the  external  cu- 
taneous nerve,  the  other,  the  common  trunk  of  the  anterior  tibial  and 
internal  cutaneous  nerves  ;(3)  Sabatier, (4)  Coopmans,(5)  andReil,(6) 
state  the  same  distribution  as  ourselves  : this  arrangement  then  should 
be  regarded  as  the  most  constant. 

b.  Tibial  nerve. 

§ 1825.  The  tibial  or  internal  •popliteal  nerve  (A',  tibialis ),  the 
largest  and  most  internal  of  the  two  terminating  branches  of  the  sciatic 
nerve,  may  be  called  the  popliteal  ( JV.  popliteus),  from  the  bifurcation  to 
the  calf  of  the  leg,  although  this  term  is  not  perfectly  exact.  It  gives 
off  first  a considerable  cutaneous  nerve,  the  long  posterior  cutaneous 
nerve  of  the  foot  and  the  leg , or  rather  the  external  cutaneous  tibial 
nerve  of  the  foot  { N . cutaneus  longus  posterior  tibiae , s.  cutaneus  pedis 
externus , s.  tibialis),  which  nevertheless  often  comes  from  the  peroneal 
nerve,  or  at  least  especially  when  the  sciatic  nerve  bifurcates  high  up> 
is  partially  replaced  either  by  the  posterior  and  inferior  branch  of  this 
latter,  or  even  by  its  inferior  and  middle  cutaneous  nerve. 

(1)  Sœmmerring,  Hirn-und  Nervenlehre,  p.  312. 

(2)  Neurologia,  p.  203. 

(3)  Sœmmerring-,  Ncrvenlehre,  p.  309. 

(4)  TV.  complet  d’anat.  ed.  3.  vol.  iii.  p.  328. 

(5V  Neurologia,  p.  201,  203. 

(6)  Anat.  descript,  vol.  iii.  p.  309. 


20 


DESCRIPTIVE  ANATOMY. 


The  external  cutaneous  tibial  nerve  of  the  foot  descends  behind  the 
muscles  of  the  foot,  goes  outward  below  the  external  malleolus,  pro- 
ceeds along  the  external  edge  of  the  foot  and  the  fibular  edge  of  the 
fifth  toe,  constituting  its  dorsal  peroneal  nerve,  and  proceeds  to  the 
top  of  it. 

The  tibial  nerve  then  gives  off  a small  branch  to  the  posterior  part 
of  the  capsule  of  the  articulation  of  the  knee.  This  branch  is  some- 
times given  off  higher  or  as  high  as  the  preceding. 

Farther  on,  the  trunk  of  the  tibial  nerve  gives  external  and  internal 
branches  to  the  three  heads  of  the  triceps,  the  plantaris,  the  popliteus, 
the  tibialis  posticus,  and  the  flexor  hallucis  longus. 

§ 1826.  The  tibial  nerve  then  goes  forward  between  the  upper  two 
heads  of  the  triceps  suræ  muscle,  descends  between  the  tendo  achillis, 
the  tibialis  posticus  and  the  flexor  hallucis  longus,  passes  behind  the 
malleolus  internus,  and  goes  to  the  sole  of  the  foot. 

Behind  the  malleolus  it  divides  into  three  branches,  one  superficial 
and  two  deep. 

§ 1827.  The  superficial  branch  or  the  external  tibial  nerve  (JV. 
tibialis  exterior ),  more  properly  the  proper  cutaneous  plantar  nerve 
(JV.  cutaneus  plantaris  proprius ),  is  distributed  to  the  skin  below  the 
malleolus  internus,  and  at  the  posterior  part  of  the  sole  of  the  foot. 

§ 1828.  The  two  deep  branches  are  the  internal  and  the  external 
plantar  nerve. 

The  internal  plantar  nerve  (JV.  plantaris  internus ) is  usually  a little 
larger  and  more  superficial  than  the  other  ; it  goes  forward  under  the 
long  head  of  the  adductor  hallucis,  between  it  and  the  flexor  communis 
digitorum  brevis,  and  divides  far  back  into  two  branches,  an  internal 
and  an  external:  the  latter  is  the  larger. 

The  internal  branch  having  given  filaments  to  the  adductor  hallucis, 
becomes  the  first  plantar  nerve  of  the  toes  ( N. . digitorum  plantaris 
primus ),  the  tibio-plantar  nerve  or  the  internal  nerve  of  the  great  toe 
(JV.  plantaris  internus , s.  tibialis  hullucis). 

The  external  branch  also  subdivides  into  two  others,  the  external  of 
which  is  also  the  larger. 

The  internal  or  the  third  plantar  nerve  of  the  toes  also  divides  into 
the  external  plantar  nerve  of  the  second  toe , and  the  internal  plantar 
nerve  of  the  third  toe. 

The  external  or  the  fourth  plantar  nerve  of  the  toes  divides  into 
the  external  plantar  nerve  of  the  third  toe , and  the  internal  plantar 
nerve  of  the  fourth. 

Thus  this  trunk  distributes  its  branches  to  the  internal  half  of  the 
skin  of  the  foot,  to  the  two  sides  of  the  three  internal  toes,  and  to  the 
internal  side  of  the  fourth. 

§ 1829.  The  external  plantar  nerve  (JV.  plantaris  externus ) goes 
forward  and  outward  between  the  flexor  communis  digitorum  brevis, 
and  the  tendon  of  the  flexor  longus,  and  divides  before  the  tuberosity 
of  the  calcanéum  into  three  branches. 


OF  THE  NERVOUS  SYSTEM. 


21 


The  internal  branch,  the fifth  plantar  nerve  of  the  toes,  which  is  en- 
tirely cutaneous,  goes  forward  to  the  anterior  extremity  of  the  tarsus, 
where  it  divides  into  the  plantar  nerve  of  the  fourth  toe,  and  the  in- 
ternal plantar  nerve  of  the  fifth. 

The  external  branch,  the  musculo-cutaneous  nerve,  goes  forward 
along  the  fibular  edge  of  the  sole  of  the  foot,  gives  filaments  to  the 
abductor  minimi  digiti  muscle,  and  becoming  the  external  plantar 
nerve  of  the  fifth  toe,  advances  to  its  extremity,  where  as  in  the  great 
toe,  it  receives  at  its  external  edge  a distinct  branch,  an  arrangement 
which  is  worthy  of  notice,  as  it  contributes  to  the  lateral  symmetry. 

This  nerve  forms  the  sixth  plantar  nerve  of  the  toes. 

The  middle,  deep,  or  muscular  trunk  is  the  largest.  It  goes  ob- 
liquely inward  and  forward,  penetrates  between  the  tendons  of  the 
extensor  longus  digitorum  communis  and  the  deep  muscles  of  the  sole 
of  the  foot,  and  distributes  itself  in  the  lumbricales,  the  adductor  and 
flexor  hallucis  muscles,  and  in  almost  all  the  internal  part  of  the 
interossei  muscles,  and  the  small  muscles  of  the  fifth  toe. 

ARTICLE  THIRD. 

OF  THE  CERVICAL  NERVES. 

§ 1830.  Till  the  time  of  Willis,  eight  cervical  nerves,  tracheliens 
Ch.  (N.  cervicales,  s.  N.  colli)(  1)  were  admitted,  but  this  anatomist 
and  many  after  him,  have  mentioned  only  seven  : as  they  consider  the 
first  cervical  as  the  last  encephalic  nerve,  an  opinion  less  correct  than 
the  ancient.  The  general  characters  of  these  eight  nerves  are  : 

1st.  Of  all  the  spinal  nerves  they  have  the  least  extent  in  the  verte- 
bral column  from  their  origin  to  the  place  where  they  penetrate  the 
dura-mater,  and  emerge  through  the  intervertebral  foramina. 

2d.  The  interna]  extremities  of  their  roots  are  closer  to  each  other 
than  those  of  the  thoracic  nerves,  but  farther  than  those  of  the  lumbar 
and  sacral  nerves. 

3d.  The  different  pairs  are  united  together  by  anastomoses  ; these 
are  usually  simple,  and  extend  from  the  inferior  edge  of  the  root  of  the 
superior  nerve,  to  the  upper  edge  of  that  of  the  lower  nerve,  and  form 
the  upper  part  of  this  last.  The  anastomosing  filaments  of  the  posterior 
roots  are  more  constant  than  those  of  the  anterior  ; the  latter  usually 
exist  only  between  the  second  and  third  pairs,  and  the  third  and  fourth, 
and  are  deficient  between  all  the  others.  On  the  contrary,  the  anas- 
tomosing filaments  of  the  anterior  roots  exist  in  almost  every  part,  but 
are  sometimes  deficient  between  the  lower  pairs.  They  are  very 
seldom  met  with  between  the  last  cervical  and  the  first  dorsal  nerve. 

We,  however,  should  observe  that  the  anastomosing  filaments  often 
do  not  exist  between  the  middle  cervical  pairs,  although  found  between 
the  superior  and  the  inferior  nerves. 

(1)  J.  Bang-,  Nervorum  cervicalium  anatomc  ; in  Ludwig,  Se.  neur, 

Vol.  III.  4 


22 


DESCRIPTIVE  ANATOMY. 


The  arrangement  of  these  filaments  is  not  always  exactly  the 
same  ; we  usually  see  a filament  which  goes  a little  obliquely  upward 
and  outward  from  the  internal  extremity  of  the  upper  edge  of  the 
lower  nerve,  towards  the  external  extremity  of  the  lower  edge  of  the 
upper  nerve.  But  sometimes  this  filament  descends  directly  from  the 
lower  edge  of  the  upper  nerve,  to  the  upper  edge  of  the  lower  nerve. 

Between  this  arrangement  and  the  preceding  is  one  which  is  inter- 
mediate, where  the  most  superior  fasciculus  of  the  lower  nerve  divides 
at  its  centre  into  two  parts,  the  upper  of  which  goes  to  the  upper 
nerve  in  the  first  .of  the  two  modes  mentioned  above,  while  the  lower 
proceeds  in  the  direction  of  the  fasciculus,  forming  the  most  upper  part 
of  the  lower  nerve.  Sometimes  one  or  two  thin  fasciculi  are  found 
between  two  pairs  of  nerves,  and  usually  a little  nearer  the  lower  than 
the  upper.  When  there  is  only  one  fasciculus,  this  divides  into  two  ; 
when  two,  they  arise  immediately  one  at  the  side  of  the  other.  In 
both  cases  either  the  fasciculi  primitively  distinct,  or  the  two  branches 
of  the  single  fasciculus  separate  from  below  upward  immediately  after 
arising,  and  form,  one  the  most  inferior  fasciculus,  the  other  the  most 
superior  of  the  pairs  between  which  they  are  situated.  Sometimes 
they  are  united  together  by  superior  and  inferior  fasciculi,  and  after- 
ward by  a transverse  filament. 

The  first  arrangement  usually  exists  between  the  inferior  cervical 
nerves,  the  third  between  the  middle,  the  second  between  the  superior, 
and  the  fourth  between  the  first  two,  counting  from  above  downward. 

The  cervical  nerves  may  be  divided  into  two  groups  ; the  first  com- 
prises the  four  lower  pairs,  the  other  the  four  upper  pairs,  for  the  first 
differ  much  from  the  second,  as  they  enlarge  to  give  origin  to  the  nerves 
of  the  upper  extremities. 

A.  INFERIOR  CERVICAL  NERVES  AND  FIRST  DORSAL  NERVE,  OR  NERVES 
OF  THE  UPPER  EXTREMITIES. 

§ 1831.  The  nerves  of  the  upper  extremities  ( JY . brachiales , s.  ex- 
tremitatis  superior  is)  ( 1 ) arise  from  the  first  dorsal  and  the  four  in- 
ferior cervical  nerves,  which  unite  at  some  distance  from  their  foramina 
to  form  the  brachial  plexus,  so  that  a greater  number  of  trunks  comes 
afterward  from  the  latter,  each  of  which  is  formed  from  the  fasciculi 
coming  from  several  of  the  carrying  nerves.  The  first  dorsal  nerve 
emerges  below  the  first  dorsal  vertebra,  the  eighth  cervical  below  the 
seventh  cervical  vertebra,  the  seventh  below  the  sixth,  the  sixth  below 
the  fifth,  and  the  fifth  below  the  fourth.  That  nerve  which  usually 
occupies  the  centre  of  the  group,  that  is  the  seventh  cervical  nerve,  is 
the  largest  : the  first  dorsal  and  the  fifth  cervical  nerves  are  the 
smallest  : the  fifth  cervical  nerve  is  smaller  than  the  first  dorsal,  and 
the  sixth  and  eighth  dorsal  are  about  the  same  size. 

(1)  J.  J.  Klint,  De  nervis  brachii,  Gottingen  ,1784. — P.  Camper,  Demonst.  anal, 
pathol.,  1.  i.  Amsterdam,  1760. 


OF  THE  NERVOUS  SYSTEM. 


23 


The  nerves  which  usually  emerge  from  the  brachial  plexus  are  the 
thoracic , the  scapular,  the  axillary,  the  radial,  the  external  cutaneous, 
the  median,  the  ulnar,  and  the  internal  cutaneous  nerves. 

§ 1832.  Before  uniting,  the  five  nerves  which  form  the  brachial 
plexus  give  off  much  smaller  posterior  branches,  which  go  to  the  deep 
dorsal  muscles  of  this  region.  The  brachial  nerves  are  then  only  the 
enlarged  anterior  branches  of  the  superior  dorsal  and  the  four  inferior 
cervical  nerves. 

§ 1833.  These  anterior  branches  descend  from  within  outward,  pass 
between  the  scalenus  anticus  and  médius  muscles,  and  soon  unite  to 
form  the  brachial  plexus  ( plexus  brachialis).{\  ) The  two  superior  and 
two  inferior  usually  unite  before  the  middle  with  the  adjacent  branches. 

The  fifth  and  the  sixth  usually  imite  the  first. 

Two  nerves  arise  from  their  union. 

The  superior  after  passing  several  inches  divides  into  two  branches, 
one  of  which  is  the  axillary  or  circumflex  nerve,  the  other  is  large  and 
unites  with  the  large  posterior  fasciculi  of  the  seventh  and  eighth  cer- 
vical nerves  to  form  the  radial  nerve. 

The  inferior,  having  proceeded  two  or  three  inches,  unites  with  one 
or  two  anterior  fasciculi  of  the  seventh  cervical  nerve,  and  thus  pro- 
duces a more  or  less  complicated  plexus,'  whence  the  external  cu- 
taneous or  the  musculo-cutaneous  nerve  wholly,  and  the  median  par- 
tially arise. 

The  seventh  cervical  nerve  divides  two  or  three  inches  from  its 
emerging  from  the  spinal  canal  into  an  anterior  and  a posterior  branch, 
of  which  the  second  is  larger. 

The  posterior  branch  blends  -with  the  upper  posterior  branch  of  the 
eighth  cervical  nerve  in  a small  trunk,  which  soon  joins  the  posterior 
branch  of  the  trunk  formed  by  the  union  of  the  fifth  and  sixth  cervical 
nerves,  and  gives  origin  to  the  radial  nerve. 

From  the  anterior  branch  and  the  common  trunk  formed  by  the 
union  of  the  fifth  and  sixth  cervical  nerves,  several  anterior  thoracic 
nerves  arise  and  then  the  musculo-cutaneous  nerve  ; it  gives  rise  with 
the  eighth  cervical  and  the  first  dorsal  nerves  to  the  median  nerve. 

The  eighth  cervical  nerve  divides  into  two  branches,  one  posterior, 
thinner  but  longer,  the  other  anterior,  shorter  but  much  thicker. 

The  posterior  unites  to  some  branches  of  the  fifth,  sixth,  and  seventh 
cervical  nerves  to  form  the  radial  nerve. 

The  anterior  joins  the  first  dorsal  nerve. 

The  common  trunk  formed  by  this  last  union,  divides  into  two 
branches,  a superior  and  an  inferior. 

The  superior,  united  with  the  fasciculi  of  the  fifth,  sixth,  and  seventh 
cervical  nerves,  becomes  the  median  nerve. 

The  inferior  forms  the  ulnar  nerve. 

The  first  dorsal  nerve  divides  into  two  other  branches,  both  of  which 
unite  with  the  eighth  cervical  nerve. 

Cl)  Bang1  (toe.  cit.)  has  figured  the  brachial  plexus— Prochaska  De  struct,  nerv., 
Vienna,  1779,  tab.  iv.  v. — Scarpa.  Annot.  anat .,  B.  1.  lab.  fi. 


24 


DESCRIPTIVE  ANATOMY. 


The  superior  assists  to  produce  the  radial  nerve. 

The  inferior  concurs  to  form  the  ulnar  nerve,  and  sometimes  alone 
produces  the  internal  cutaneous  nerve. 

I.  THORACIC  NERVES. 

§ 1834.  The  thoracic  nerves , sterno-tlioraciques,  Ch.  (JV.  tlioracici) 
may  be  distinguished  into  posterior  and  anterior. 

The  posterior  arise  from  the  branches  of  the  fifth  and  sixth,  some- 
times also  from  the  seventh  cervical  nerve,  which  are  mostly  united  in 
a nerve  which  descends  on  the  external  face  of  the  serratus  major 
muscle,  and  is  distributed  in  that  muscle. 

The  anterior  arise  from  the  anterior  trunk  formed  by  the  union  of 
the  fifth  and  sixth  cervical  nerves,  and  also  from  the  anterior  branch  of 
the  seventh  and  eighth,  descend  from  behind  forward,  and  give  filaments 
to  the  subclavius,  the  pectoralis  major  and  minor  muscles,  the  thymous 
gland,  and  the  skin  of  the  anterior  and  superior  part  of  the  chest  and 
shoulder,  where  they  anastomose  with  some  filaments  of  the  fourth 
cervical  and  axillary  nerves. 

II.  SCAPULAR  NSRVE. 

§ 1835.  The  scapular  nerve  (JV*.  scapularis ),  which  is  rather  large 
often  comes  from  the  fifth  cervical  nerve  before  it  joins  with  the  follow- 
ing. When  it  arises  only  after  the  union,  it  commences  almost  in  the 
place  where  it  is,  passes  through  the  coracoid  notch  of  the  scapula, 
arrives  thus  on  the  posterior  face  of  the  scapula,  sends  filaments  to  the 
supraspinatus  muscle,  goes  downward  over  the  neck  of  the  scapula, 
and  arrives  at  the  infraspinal  fossa,  where  it  is  distributed  to  the 
infraspinatus  and  teres  minor  muscles. 

HI.  AXILLARY  NERVE. 

§ 1836.  The  axillary  nerve,  scapulo-humeral , Ch.  ( JV.  axillaris , s. 
circumflexus  brachii),  or  more  properly  the  circumflex  nerve,  arises 
from  the  posterior  and  superior  branch  coming  from  the  division  of  the 
common  trunk  formed  by  the  union  of  the  fifth  and  sixth  cervical 
nerves.  It  first  sends  branches  to  the  infraspinatus  muscle,  which 
often  receives  a large  one  from  the  common  trunk  mentioned  above,  it 
then  gives  some  to  the  teres  minor  and  major  muscles,  then  passing 
between  these  two  muscles  and  the  long  head  of  the  triceps  extensor, 
it  is  reflected  outward  and  backward  on  the  head  of  the  humerus,  ex- 
pands in  the  deltoides  muscle,  and  finally  becoming  the  cutaneous 
nerve  of  the  shoulder  (JV.  cutaneus  humeri ),  together  with  the  fourth 
cervical  nerve  sends  filaments  to  the  integuments  of  this  region. 


OF  THE  NERVOUS  SYSTEM. 


25 


IY.  RADIAL  NERVE. 

§ 1837.  The  radial  nerve,  radio-digital,  Ch.  (JV.  radialis),  is  much 
larger  than  the  preceding,  arises  from  fasciculi  of  all  the  brachial  nerves 
by  three  branches,  which  come  one  from  the  seventh  cervical  nerve 
only,  the  second  from  the  fifth  and  sixth,  and  the  third  from  the  eighth 
cervical  and  the  first  dorsal  nerves.  Soon  after  its  origin,  it  gives  a 
large  branch  to  the  latissimus  dorsi  and  filaments  to  the  triceps  ex- 
tensor muscles.  A little  below  the  middle  of  the  arm  it  turns  on  the 
humerus,  often  reappearing  on  its  anterior  face  between  the  brachialis 
intemus  and  the  supinator  longus  muscles. 

In  turning  on  the  humerus  it  gives  a long  and  thin  cutaneous 
branch,  the  superior  external  cutaneous  nerve  (JV.  cutaneus  externus 
superior).  This  nerve  descends  along  the  radial  edge  and  the  inner 
face  of  the  fore-arm,  and  interlaces  with  the  cutaneous  branch  of  the 
musculo-cutaneous  nerve,  extends  a greater  or  less  distance  to  the 
middle  of  the  fore-arm,  to  the  carpus,  and  even  the  thumb. 

The  trunk  of  the  radial  nerve  then  gives  branches  to  the  supinator 
longus  and  the  extensor  carpi  longus  radialis  muscles.  It  divides  at 
the  lower  extremity  of  the  fore-arm  into  two  branches,  a superficial  or 
cutaneous  and  a deep  or  muscular. 

The  superficial  branch  (R.  superficialis  dorsalis,  s.  cutaneus)  de- 
scends along  the  anterior  edge  of  the  radius  between  the  supinator 
longus  and  the  radiales  muscles,  arrives  at  the  outer  face  of  the  fore- 
arm, passing  below  the  tendons  of  the  first  of  these  three  muscles,  and 
divides  usually  some  inches  below  the  inferior  extremity  of  the  fore-arm 
into  two  almost  equal  branches,  the  anterior  being  a little  the  larger, 
which  distribute  filaments  to  the  anterior  region  of  the  integuments 
of  the  back  of  the  hand,  and  to  the  dorsal  face  of  the  three  anterior 
fingers. 

The  anterior  branch  anastomoses  in  several  places  with'those  of  the 
cutaneous  branch  of  the  musculo-cutaneous  nerve,  sends  filaments  to 
the  skin  of  the  radial  side  of  the  carpus  and  metacarpus,  and  divides 
on  the  carpus  into  two  small  branches,  the  clo7'sal  «erres  ofi  the  thumb 
(JV.  cutanei  pollicis  dorsales),  which  descend  on  its  dorsal  side  along 
the  radial  and  ulnar  edges  to  its  anterior  extremity,  furnish  filaments 
to  its  dorsal  face,  and  anastomose  together  and  with  the  palmar  nerves 
of  the  thumb. 

The  posterior  branch  usually  divides  soon  after  arising  into  two 
principal  ramuscules,  an  anterior  and  posterior. 

The  anterior  goes  to  the  skin  between  the  thumb  and  index  finger, 
and  arrived  at  the  radial  side  of  the  last  finger  becomes  the  radio- 
dorsal nerve  of  the  index  finger  (JV.  dorsalis  radialis  indicus). 

The  posterior  soon  subdivides  into  two  filaments,  one  of  which  pro- 
duces the  cubito-dorsal  nerve  of  the  index  finger  and  the  radio-dorsal 
nerve  of  the  middle  finger,  while  the  second  is  the  cubito-dorsal  nerve 
of  the  middle  finger. 


26 


DESCRIPTIVE  ANATOMY. 


All  these  ramifications  frequently  anastomose  with  each  other  or 
with  those  of  the  ulnar  nerve,  and  thus  give  rise  to  a plexus  called  the 
dorsal  arch  of  the  hand  ( rete , s.  arcus  dorsalis  manus ). 

The  deeper  or  larger  muscular  branch  gives  off  branches  for  the  ra- 
dialis  brevis  and  the  supinator  brevis  muscles  ; it  then  turns  over  these 
muscles  and  engages  itself  between  their  fibres,  penetrates  between 
the  extensor  digitorum  communis  muscle,  arrives  at  the  posterior  sur- 
face of  the  fore-arm,  gives  off  some  large  branches,  some  of  which  are 
recurrent  to  the  extensor  digitorum  communis,  to  the  extensor  minimi 
digiti,  and  to  the  ulnaris  internus  and  externus  muscles.  Then  as  the 
external  interosseus  nerve  ( JY.  interosseous  externus),  it  descends  on  the 
extensor  and  the  adductor  pollicis  longus  muscles,  to  which  it  sends 
filaments,  as  also  to  the  extensor  indicis  proprius  muscle,  and  is  finally 
lost  in  the  capsule  of  the  wrist-joint. 


V.  EXTERNAL  CUTANEOUS  NERVE. 

§ 1838.  The  external  cutaneous  nerve,  or  muscido-cutaneous  nerve, 
or  the  perforating  nerve  of  Casserius,  radio-cutané , Ch.  (JY.  cutaneus 
externus,  s.  musculo-cutaneus,  s.  perforons  Casserii),  is  much  smaller 
than  the  preceding,  although  it  descends  almost  as  low  as  it.  It  arises 
from  the  fasciculi  of  the  fifth,  sixth,  and  seventh  cervical  nerves.  It 
sometimes  comes  from  the  median  nerve. 

It  frequently  but  not  always  penetrates  the  coraco-brachialis  muscle. 
When  this  is  not  the  case,  it  passes  on  the  internal  edge  of  this  muscle, 
being  joined  to  it  only  at  its  surface.  It  divides  high  up  in  the  arm 
into  two  branches,  the  one  muscular  and  small,  the  other  cutaneous 
and  larger. 

The  muscular  branch  gives  filaments  to  the  coraco-brachialis 
muscle,  to  the  two  heads  of  [the  biceps,  and  to  the  bracliialis  internus 
muscle. 

The  cutaneous  branch  passing  between  the  biceps  and  the  brachialis 
internus  muscle,  arrives  at  the  anterior  edge  of  the  arm,  descends  on  the 
radial  side  in  the  aponeurosis,'  accompanying  the  cephalic  vein.  It  anas- 
tomoses frequently  above  with  the  external  cutaneous  nerve,  and  below 
with  the  dorsal  branch  of  the  radial  nerve  ; it  is  distributed  to  the  skin 
of  the  posterior  surface  of  the  fore-arm  and  the  hand,  and  terminates  at 
the  thumb. 


VI.  MEDIAN  NERVE. 

§ 1839.  The  median  nerve,  mcdio-digital , Ch.  (JY.  mcdianus ),  the 
largest  nerve  of  the  upper  extremity,  comes  also  from  the  brachial 
plexus.  It  descends  on  the  inside  of  the  arm  near  its  lower  extremity 
without  giving  off  any  branch,  unless  it  be  sometimes  the  external 
cuianeous  nerve. 


OF  TKB  NERVOUS  SYSTEM. 


27 


Some  inches  below  the  elbow-joint  it  gives  several  small  muscular 
branches  to  the  pronator  teres,  to  the  upper  part  of  the  radialis  internus, 
the  palmaris  longus,  and  to  the  upper  part  of  the  flexor  digitorum  brevis 
muscles.  Near  the  elbow  it  gives  off  a considerable  branch,  the  inter- 
nal interrosseus  nerve  (N.  interrosseus  internus ),  which  descends  before 
the  flexor  communis  digitorum  profundus,  distributes  branches  to  this 
muscle  and  to  the  flexor  pollicis  longus,  is  reflected  on  the  anterior 
edge  of  the  pronator  quadratus,  arrived  thus  at  the  posterior  face  of  the 
fore-arm,  it  terminates  in  this  muscle. 

The  trunk  descends  before  the  flexor  digitorum  profundus,  between 
the  bones  of  the  fore-arm,  gives  off  filaments  to  this  muscle  and  to  the 
palmaris  longus,  and  gives  a cutaneous  branch  which  is  distributed  in 
the  integuments  of  the  palmar  face  of  the  carpus,  where  it  anasto- 
moses with  the  branches  of  the  musculo-cutaneous  nerve  and  the  ulnar 
nerve.  It  then  divides  near  the  lower  third  of  the  fore-arm  into  two 
branches,  an  anterior  or  radial  and  a posterior  or  ulnar  ; the  first  is  the 
larger. 

These  branches  descend  without  giving  any  twig  to  the  fore-arm 
between  the  tendons  of  the  flexors,  with  which  they  pass  under  the 
ligaments  of  the  carpus,  where  they  usually  unite  by  some  transverse 
fibres.  At  the  palm  of  the  hand  they  separate. 

The  radial  branch  divides  at  the  carpus  into  an  anterior  and  posterior 
twig. 

The  anterior  very  soon  divides  into  three  filaments,  the  radio-palmar 
and  the  cubito-palmar  nerves  of  the  thumb,  and  the  radio-palmar  nerve  of 
the  index  finger  , these  frequently  anastomose  together,  extend  to  the 
extremities  of  these  two  fingers,  and  terminate  by  considerable 
branches,  and  give  filaments  to  the  first  lumbiicalis  muscle. 

The  posterior  then  sends  a large  branch  to  the  adductor  brevis,  to 
its  opponens  muscle  and  the  flexor  pollicis  brevis,  after  which  it  be- 
comes the  cubito-palmar  nerve  of  the  index  finger. 

§ 1840.  The  cubital  branch  divides  at  the  commencement  of  the 
carpus  into  two  twigs. 

The  anterior  which  is  smaller  sends  filaments  to  the  second  lum- 
bricalis  muscle,  and  becomes  the  radio-palmar  nerve  of  the  third  finger. 

The  posterior  which  is  larger  sends  filaments  to  the  integuments  of 
the  hand,  soon  divides  into  two  ramuscules,  the  cubito-palmar  nerve  of 
the  third  finger  and  the  radio-palmar  nerve  of  the  fourth. 


VII.  ULNAE  OR  CUBITAL  NERVE. 

§ 1841.  The  ulnar  nerve,-  cubito-digital  ( JY . ulnar  is.  s.  cubitalis),  is 
a little  smaller  than  the  preceding,  and  arises  from  the  three  inferior 
nerves  of  the  brachial  plexus.  It  descends  inward  and  backward,  gives 
off  no  branches  along  the  arm  except  sometimes  the  internal  cutaneous 
nerve,  and  arrives  at  the  ulnar  side  of  the  fore-arm,  passing  imme- 


28 


DESCRIPTIVE  ANATOMY. 


diately  behind  the  internal  condyle  of  the  humerus,  where  it  may  be 
easily  compressed. 

Arrived  at  the  fore-arm,  it  first  gives  off  ramifications  to  the  flexor 
digitorum  profundus  and  to  the  flexor  carpi  ulnaris,  and  then  sends 
under  the  skin  along  the  basilic  vein  a small  branch,  called  the  long 
palmar  nerve  (JV.  ulnaris  longus  palmaris),  which  anastomoses  in  the 
carpus  with  an  analogous  branch  coming  from  the  median  nerve  ; 
about  the  middle  of  the  fore-arm,  it  divides  into  two  branches,  a dorsal 
and  a palmar. 

The  dorsal  branch  (JV.  ulnaris  dorsalis ) passes  between  the  ulna 
and  the  tendon  of  the  flexor  carpi  ulnaris  muscle,  comes  on  the  back 
of  the  fore-arm,  where  it  subdivides  into  two  twigs. 

The  posterior  or  ulnar  supplies  the  skin  of  the  ulnar  side  of  the  hand, 
and  becomes  the  cubito-dorsal  nerve  of  the  fifth  finger. 

The  anterior  or  the  radial  also  soon  divides  into  two  principal  fila- 
ments, one  of  which  is  the  radio-dorsal  nerve  of  the  fifth  finger  and  the 
cubito-dorsal  nerve  of  the  fourth , the  other  is  the  radio-dorsal  nerve  of 
the  fourth  finger. 

This  dorsal  branch  is  distributed  like  the  dorsal  branch  of  the  radial 
nerve. 

The  palmar  branch  ( JV.  ulnaris  palmaris ) which  is  larger,  descends 
between  the  tendons  of  the  ulnaris  internus  and  the  flexor  digitorum 
communis  muscles,  and  divides  on  the  ulnar  edge  of  the  carpus  into  a 
superficial  and  a deep  twig. 

The  deep  or  muscular  twig  goes  downward  and  forward  between 
the  adductor  and  flexor  minimi  digiti  muscles,  passes  across  to  the 
radial  side  of  the  hand,  going  between  the  tendons  of  the  flexor  com- 
munis and  interossei  muscles,  and  sends  numerous  twigs  to  the  mus- 
cles of  the  little  finger,  to  the  interossei  and  lumbricales,  and  to  the 
adductor  pollicis  muscles. 

The  superficial  or  cutaneous  branch  is  smaller  than  the  preceding, 
anastomoses  by  one  or  several  filaments  with  the  cubito-palmar  branch 
of  the  median  nerve  (from  this  union  we  have  a superficial  palmar 
arch),  and  soon  divides  into  two  filaments,  an  anterior  and  a posterior. 

The  anterior  soon  divides  into  the  cubito-palmar  nerve  of  the  fifth 
finger  and  the  common  trunk  of  the  cubito-palmar  nerve  of  the  fourth , 
and  the  radio  palmar  nerve  of  the  fifth. 

Each  finger  receives  two  palmar  and  two  dorsal  branches,  the  first 
of  which  are  the  largest.  They  proceed  along  the  radial  and  ulnar  edges 
of  the  finger  directly  at  the  side  of  the  digito-palmar  artery,  more  in- 
ward and  downward  than  it,  that  is,  nearer  the  palmar  face,  as  like- 
wise the  superficial  palmar  arch  is  nearer  the  surface  than  their  trunk. 
They  go  to  the  extremity  of  the  fingers.  In  this  passage  they  give 
off  several  large  branches,  distribute  some  small  twigs  to  the  palmar 
face  of  the  finger,  when  they  anastomose  with  each  other. 


or  THE  NERVOUS  SYSTEM. 


29 


VIII.  INTERNAL  CUTANEOUS  NERVE. 

§ 1842.  The  internal  cutuneous  nerve,  cubito-cutané,  Ch.  (JV.  cu- 
taneus  internus ),  usually  arises  from  the  first  dorsal  by  several  roots  ; 
it  sometimes  though  rarely  comes  from  the  ulnar,  being  the  first  branch. 
It  descends  directly  below  the  skin  at  the  side  of  the  basilic  vein  in  the 
arm.  From  its  upper  part  arises  the  superior  cutaneous  nerve  (A’. 
cutaneus  internus  superior ),  which  sometimes  comes  from  the  ulnar 
nerve,  and  is  distributed  to  the  triceps  extensor  muscle  and  the  skin 
which  covers  it.  A little  lower  it  gives  off  the  inferior  internal  cutaneous 
nerve  (A*.  cutaneus  internus  inferior ),  which  distributes  its  branches  to 
the  lower  part  of  the  triceps  extensor  muscle,  to  the  skin  of  the  elbow, 
to  the  integuments  of  the  ulnar  edge  of  the  fore-arm,  and  to  the  carpus, 
and  which  terminates  on  the  cubital  edge  of  the  hand  and  little  finger, 
descending  along  the  basilic  vein,  and  anastomosing  with  the  branches 
of  the  ulnar  nerve,  which  it  meets  in  its  course. 

In  the  whole  course  of  this  nerve  its  different  branches  anastomose 
frequently  with  each  other  and  with  those  of  the  external  cutaneous 
nerve  on  the  posterior  side  of  the  fore-arm. 


B.  SUPERIOR  CERVICAL  NERVES. 

§ 1843.  The  four  superior  cervical  nerves  are  smaller  than  the 
inferior.  Like  the  latter  their  size  increases  progressively  from  above 
downward,  so  that  the  second  and  third  are  the  largest.  They  form 
with  the  lower  ones  an  uninterrupted  series  ; and  like  them  their  an- 
terior branches  immediately  after  their  trunks  have  come  from  the 
intervertebral  foramina,  give  off  twigs  which  anastomose  with  the 
adjacent  branches  and  form  the  cervical  plexus , trachélo-sous-cutané, 
Ch.  ( plexus  cervicalis).  This  plexus  descends  along  the  corresponding 
vertebrae,  below  the  sterno-cleido-mastoideus  muscle,  outside  of  the  in- 
ternal jugular  vein,  carotid  artery,  and  pneumogastric  nerve,  on  the 
scalenus  posticus  muscle.  It  anastomoses  below  with  the  brachial 
plexus,  within  with  the  superior  and  middle  cervical  ganglions  of  the 
great  sympathetic  nerve.  We  have  as  much  reason  to  think  the  dif- 
ferent branches  of  the  cervical  nerves  are  derived  from  them  as  that 
they  arise  from  the  cervical  pairs  themselves. 

Some  modern  anatomists,  among  whom  are  Bichat(l)  and  Clo- 
quet,(2)  have  adopted  this  method,  and  describe  separately  only  the 
posterior  branches  and  the  commencement  of  the  anterior,  and  consider 
the  cervical  plexus  as  the  origin  of  all  the  nerves  which  arise  after  the 
union  of  the  anterior  branches.  But  we  shall  not  follow  them,  as  the 


(1)  Anat.  descript.,  vol.  iii.  p.  234-246. 

(2)  Tr.  d'anat.,  vol.  ii.  p.  633-641. 

5 


VOL.  III. 


30 


DESCRIPTIVE  ANATOMY. 


nerves  of  which  they  treat  seem  to  arise  from  some  particular  pairs 
which  are  not  seen  in  the  other  plexiform  nerves  of  the  spinal  marrow. 

The  diaphragmatic  nerve  is  the  only  one  to  be  considered  sepa- 
rately, because  produced  not  only  by  several  pairs  of  the  cervical 
plexus  but  also  of  the  brachial  plexus,  so  that  it  seems  to  belong  in 
common  to  the  superior  and  inferior  section  of  the  cervical  nerves. 


I.  DIAPHRAGMATIC  NERVE. 


§ 1844.  The  diaphragmatic  or  phrenic  nerve  (JV.  diaphragmati- 
ons, s.  phrenicus){l ) arises  by  several  branches  from  the  lower  extre- 
mity of  the  brachial  plexus.  The  largest  branch  is  always  furnished 
by  the  anterior  branch  of  the  fourth  pair,  but  a smaller  one  always 
arises  from  the  third  and  often  from  the  second,  and  about  three  from 
the  brachial  plexus.  This  nerve  sometimes  joins  the  ascending  branch 
of  the  hypoglossal  nerve. 

The  diaphragmatic  nerve  descends  on  the  side  of  the  neck  between 
the  rectus  capitis  anticus  and  the  scalenus  muscle,  gives  branches  to 
these  muscles  and  to  the  thymous  gland,  anastomoses  by  a few  filaments 
with  the  inferior  and  middle  cervical  ganglions  of  the  great  sympa- 
thetic nerve,  enters  the  chest  between  the  subclavian  artery  and  vein, 
then  goes  forward,  descends  before  the  pulmonary  vessels,  and  lastly 
passes  between  the  internal  wall  of  the  external  sac  of  the  pleura  and 
the  pericardium,  applied  very  exactly  to  the  surface  of  this  last  mem- 
brane, and  is  finally  distributed  to  the  diaphragm.  A little  before 
arriving  at  this  muscle,  it  divides  into  several  branches  which  are 
united  by  intermediate  filaments,  some  of  which  go  to  the  convex  face 
of  the  diaphragm  and  others  pass  through  its  costal  portion  and  its 
central  tendon,  accompany  the  ascending  vena-cava  on  the  right,  with 
which  they  emerge  through  the  foramen  quadratum,  come  into  the 
abdomen,  where  they  not  only  expand  on  the  inferior  face  of  the  mus- 
cle, but  also  anastomose  by  several  filaments  with  the  solar  plexus  of 
the  great  sympathetic  and  with  the  gastric  branch  of  the  pneumo-gas- 
tric  nerve.  These  anastomotic  filaments  almost  always  project  at  in- 
tervals, and  these  projections  often  form  real  ganglions. 

The  left  diaphragmatic  nerve  is  situated  farther  back,  and  is  longer 
than  the  right,  as  it  turns  around  on  the  summit  of  the  heart.  Be- 
sides the  filaments  it  gives  to  the  diaphragm,  it  sends  some  also  to  the 
lower  part  of  the  esophagus. 


(1)  Kruger,  De  nervo  phrenico,  Leipsic,  1758. 


OF  THE  NERVOUS  SYSTEM. 


31 


It.  FOURTH  CERVICAL  NERVE. 

§ 1845.  The  fourth  cervical  nerve(l)  is  a little  smaller  than  the  two 
adjacent.  It  emerges  through  the  third  intervertebral  foramen,  be- 
tween the  anterior  and  posterior  intertransversarii  muscles,  and  imme- 
diately divides  into  an  anterior  and  a posterior  branch. 

The  posterior  is  the  smaller  and  deeper  : it  anastomoses  with  a 
branch  of  the  third  cervical  nerve,  gives  a twig  to  the  complexus 
muscle,  passes  transversely  between  this  muscle  and  the  semispinalis 
colli,  to  which  also  it  sends  large  filaments,  also  to  the  multifidus 
spinæ,  then  penetrates  between  the  complexus  and  trapezius  muscles, 
and  expands  in  the  corresponding  skin  of  the  neck. 

The  anterior  branch,  which  is  the  larger,  first  gives  off  a filament 
to  the  rectus  capitis  major  anticus  muscle  : then  it  sends  one  of  anas- 
tomosis to  the  cervical  portion  of  the  great  sympathetic  nerve,  or  to  its 
superior  cervical  ganglion.  It  usually  gives  off  also  a twig  to  the 
descending  branch  of  the  hypoglossal  nerve,  and  constantly  sends  fila- 
ments to  the  levator  anguli  scapulæ  muscle. 

It  then  sends  an  ascending  anastomotic  twig  to  the  anterior  branch 
of  the  third  cervical,  and  forms  with  it  the  third  cervical  nervous  plexus , 
then  divides  into  three  or  four  twigs  which  also  proceed  from  above 
downward,  and  are  called  the  supraclavicular  nerves  (JY.  supra-clavi- 
culares).  The  latter  are  distributed  principally  to  the  skin  which 
covers  the  clavicle  and  the  shoulder. 

The  anterior  (JY.  supra-clavicidares  anteriores ) are  distributed  to  the 
skin  which  covers  the  first  piece  of  the  sternum  and  the  sternal  ex- 
tremity of  the  clavicle  to  the  mamma,  anastomose  with  the  anterior 
thoracic  nerves  coming  from  the  fifth  cervical,  and  send  filaments  also 
to  the  subclavius  muscle. 

The  middle  (JY.  supra-clavicidares  medii ) are  distributed  to  the  tra- 
pezius muscle  and  the  posterior  belly  of  the  omo-hyoideus  muscle,  and 
also  to  the  skin  which  covers  the  body  of  the  clavicle,  its  scapular 
extremity,  and  the  scapula. 

The  posterior  (JY.  supra-claviculares  posteriores ) go  to  the  skin  of 
the  neck  and  of  the  shoulder. 

A small  ascending  branch  generally  arises  from  the  anterior  or 
the  middle  nerve  ; this  forms  a very  broad  plexus  by  anastomosing 
with  the  middle  subcutaneous  cervical  nerve,  which  comes  from  the 
third  pair. 

The  middle  and  the  posterior  anastomose  with  the  accessory  nerve 
partly  in  the  skin,  and  partly  in  the  trapezius  muscle. 


(1)  G.  F.  Peipers,  Diss.  sistens  tertii  et  quarti  nervorum  cervicalium  descrip- 
tionem , cut  accedit  succincta  eorundcm  nervorum  quinti , nervi  phrenici , prœsertim 
ratione  originis  nervi  duri  ejusque  prœsertim  rami  inferioris , nervi  hypoglossi  et 
occipitalis  maximi  a secundo  cervicalium  nervo  adumbratio,  Halle,  1793. 


32 


DESCRIPTIVE  ANATOMY. 


III.  THIRD  CERVICAL  NERVE. 

§ 1S46.  The  third  cervical  nerve(  1)  is  larger  than  the  preceding. 
It  emerges  from  the  spinal  canal  between  the  second  and  the  third 
cervical  vertebne,  and  divides  into  two  branches,  a posterior  and  an 
anterior. 

The  posterior  branch  is  much  smaller  than  the  anterior  ; it  proceeds 
from  before  backward  between  the  anterior  and  posterior  intertrans- 
versarii  muscles,  gives  filaments  to  these  two  muscles  and  also  to  the 
transversalis  colli  and  the  complexus  minor  muscles,  goes  backward 
passing  on  this  latter,  sends  anastomosing  filaments  to  the  posterior 
branch  of  the  second  and  third  cervical  nerves,  and  also  to  the  small 
occipital  nerve  which  comes  from  the  anterior  branch  of  the  third  pair, 
glides  below  the  biventer  cervicis  nuchæ  and  the  complexus  major 
muscles,  which  receive  considerable  filaments  from  it,  and  goes  directly 
to  the  trapezius  muscle  in  which  it  is  distributed,  and  also  in  the  middle 
region  of  the  skin  of  the  neck. 

The  anterior  branch  sends  first  small  twigs  to  the  rectus  capitis 
major  anticus  and  to  the  longus  colli  muscles,  then  proceeds  from  above 
downward  and  divides  into  two  branches,  a descending  and  an  as- 
cending. 

The  descending  branch,  the  superficial  cervical  nerve,  the 
submental  nerve,  Ch.  ( JV.  superficialis  colli,  s.  profundus,  JV.  sub-cu- 
taneus  colli  médius)  turns  on  the  posterior  edge  of  the  sterno- 
cleido-mastoideus  muscle,  to  go  to  the  outer  face  of  this  muscle,  to 
which  it  gives  filaments,  sends  others  which  anastomose  with  the 
ascending  branch,  and  terminates  first,  by  descending  ramifications 
called  the  middle  and  inferior  subcutaneous  cervical  nerves  ( JV.  subcu- 
tanei  colli  medii  et  inferiores),  in  the  middle  and  lower  part  of  the  skin 
of  the  neck  ; second,  by  ascending  twigs  which  anastomose  fiequently, 
both  with  each  other  and  with  the  final  twigs  of  the  facial  nerve  in  the 
skin  which  covers  the  ascending  and  horizontal  branches  of  the  lower 
jaw  from  the  lobe  of  the  ear  to  the  chin,  and  thus  form  the  superior 
subcutaneous  cervical  nerves  (JV.  subcidanei  colli  superiores). 

The  highest  and  most  posterior  portion  of  this  descending  branch,  or 
the  great  auricidar  nerve,  the  zygomato-auricular  nerve,  Ch.  (JV. 
auricularis  magnus , s.  cervicalis),  goes  directly  upward,  and  passing 
behind  the  ascending  branch  of  the  lower  jaw  arrives  at  the  exter- 
nal ear.  Its  ramifications  are  distributed  from  behind  forward  and 
from  below  upward  in  the  integuments  and  posterior  muscles  of  the 
external  ear,  and  also  in  the  skin  of  the  auditory  foramen. 

The  uscending  branch  goes  backward  and  upward,  gives  off  first  an 
ascending  anastomosing  filament  which  unites  to  a descending  filament 
of  the  third  pair  to  form  the  second  cervical  nervous  plexus,  and  often 
sends  off  immediately  the  great  auricular  nerve.  In  this  case  its  pos- 

(1)  Peipers,  loc.  til. — Vic-d’Azyr,  Mêmoiré  sur  les  nerfs  de  la  seconde  et  de  la  troi- 
séme  paire  cervicale  ; in  the  Mém.  de  Paris,  1777,  p.  21-40. 


OF  THE  NERVOUS  SYSTEM. 


33 


tenor  part,  and  when  the  great  auricular  nerve  comes  from  the  de- 
scending branch,  its  entire  trunk  becomes  the  small  or  the  anterior 
occipital  nerve  (JV.  occipitalis  minor,  s.  anterior ),  which  most  generally 
soon  divides  into  several  filaments,  ascends  on  the  complexus  minor 
and  splenius  capitis  muscles  and  expands  in  the  skin  of  the  occiput, 
in  that  of  the  mastoid  process,  in  that  of  the  posterior  and  superior  part 
of  the  external  ear  between  the  superior  and  posterior  auricular 
muscles,  farther  forward  than  the  large  occipital  nerve  given  off  by  the 
second  cervical  pair,  although  anastomosing  frequently  with  this  latter, 
as  with  the  filaments  of  the  facial  nerve. 

IV.  SECOND  CERVICAL  NERVE. 

§ 1847.  The  second  cervical  nerve(l)  emerges  from  the  spinal  canal 
between  the  first  and  second  cervical  vertebra.  It  is  larger  than  the 
third,  and  divides  into  an  anterior  and  a posterior  branch,  directly  below 
the  ganglion. 

The  posterior  branch,  the  great  occipital  nerve  (JV.  occipitalis  maxi- 
mus ),  is  much  larger  than  the  anterior,  which  is  contrary  to  the  ar- 
rangement of  the  inferior  cervical  nerves  except  the  first,  and  to  that 
of  all  the  other  spinal  nerves.  It  goes  directly  backward  below  the 
complexus  minor  muscle,  first  sends,  filaments  to  the  obliquus  capitis 
inferior  muscle,  gives  off  others  which  pass  on  this  muscle  to  anasto- 
mose with  the  first  and  third  cervical  nerves,  also  gives  them  to  the 
upper  part  of  the  two  splenii  muscles,  to  the  biventer  cervicis,  the 
complexus  and  trapezius  muscles  under  which  it  proceeds,  to  the  mul- 
tifidus  spinse  and  to  the  skin  of  the  neck,  approaches  the  median  line, 
and  arrives  at  the  occipital  bone  ; it  there  forms  most  of  the  nerves  in 
this  region,  ramifies  to  the  lambdoidal  suture,  where  its  filaments  ex- 
pand in  the  skin  and  occipitalis  muscle,  and  anastomose  with  those  of 
the  facial  and  small  occipital  nerve. 

The  anterior  branch  is  smaller  than  the  preceding  ; it  goes  forward 
and  outward  under  the  obliquus  capitis  superior  muscle,  and  soon  di- 
vides into  two  anastomotic  branches,  a superior,  ascending  (JV'.  anasto 
moticus  adscendens ),  and  an  inferior,  descending  (JV'.  anastomoticns 
descendais),  which  unite,  the  first  with  the  anterior  branch  of  the  first 
cervical  nerve,  to  form  the  first  cervical  nervous  plexus  ; the  other  with 
the  anterior  branch  of  the  third,  to  form  the  second  cervical  nervous 
'plexus. 

From  the  upper  branch  arise  filaments  which  enter  the  superior  cer- 
vical ganglion  of  the  great  sympathetic,  the  sublingual,  and  the 
pneumo-gastric  nerve  : one  arises  even  from  the  bifurcation  and  goes 
into  the  superior  cervical  ganglion  ; finally  the  inferior  branch  produces 
one  which  is  larger,  which  descends  from  behind  forward  and  anasto- 
moses with  a similar  twig  from  the  anterior  branch  of  the  third  cervical 
nerve,  and  with  the  descending  branch  of  the  sublingual  nerve. 


(1)  Vicq-d’Azyr,  loc.  cit. 


34 


DESCRIPTIVE  ANATOMY. 


V.  FIRST  CERVICAL  NERVE. 

§ 1848.  The  first  cervical  nerve,  called  also  the  suboccipital  or  the 
tenth  encephalic  nerve  (JV.  cervicalis  primus , s.  supremus,  s.  occipitalis , 
s.  infra-occipitalis,  s.  decimus  cerebri), (1)  is  frequently  the  smallest  of 
all  the  spinal  nerves,  since  it  is  not  unfrequently  smaller  than  the  last 
sacral  nerve  ; at  least  it  is  always  smaller  than  the  other  nerves  of  the 
spinal  marrow,  except  the  last.  By  its  situation,  origin,  and  direction, 
it  makes  the  transition  from  the  spinal  to  the  encephalic  nerves,  for  it 
frequently  in  the  same  and  still  more  so  in  different  subjects  resembles 
the  former  in  some  characters,  the  latter  in  others. 

Hence  for  a long  time,  that  is,  since  Willis  lived,  it  has  been  consi- 
dered as  an  encephalic  nerve,  the  tenth  cerebral  nerve.  It  is  not  till 
lately  that  it  has  been  generally  admitted  among  the  spinal  nerves,  to 
which  it  is  more  similar  than  to  the  cerebral  nerves. 

It  arises  out  of  the  skull  from  the  upper  extremity  of  the  spinal 
marrow  between  the  occipital  portion  of  the  basilar  bone  and  the  first 
cervical  vertebra. 

Very  often,  perhaps  even  most  generally,  although  Huber  considers 
the  existence  of  two  roots  as  a constant  fact, (2)  it  arises  by  one  an- 
terior root  which,  like  that  of  the  sublingual  nerve,  comes  from  the  an- 
terior cord  of  the  spinal  marrow. (3) 

Even  when  a posterior  root  exists,  the  anterior  is  much  larger  than 
it,  and  is  composed  of  from  two  or  three  to  seven  fasciculi,  rarely  of 
eight,  more  commonly  of  two  or  three.  These  fasciculi,  situated  one 
above  another,  are  also  formed  of  smaller  filaments.  The  posterior  root 
presents  only  from  one  to  three,  and  rarely  four  filaments  which  are 
much  smaller,  the  inferior  of  which,  a remarkable  fact,  is  generally 
much  larger  than  the  others  : these  filaments  commonly  unite  in  two 
fasciculi  which  proceed  the  superior  outward,  the  inferior  upward. 

Even  when  the  posterior  root  exists,  the  nerve  however  is  most 
generally  formed  anteriorly  by  but  one  root,  the  anterior,  for  the  latter 
ascends  more  than  the  posterior. 

The  posterior  root  is  generally  situated  behind  the  accessory  nerve  ; 
sometimes,  however,  but  very  rarely  (we  have  never  observed  it),  it 
passes  before.  It  is  then  in  this  latter  case  unusually  near  the  ante- 
rior, although  the  ligamentum  centiculatum  even  then  always  sepa- 
rates it  from  them.  Farther  it  is  constantly  nearer  the  anterior  face 
than  are  the  posterior  roots  of  the  other  spinal  nerves. 


(1)  G.  T.  Asch,  De  primo  pare  nervorum  medullas  spinalis,  Gottingen,  1750. — Sa- 
batier, Sur  les  nerfs  de  la  dixième  paire  ; in  the  Mém.  présentés,  vol.  vit.,  p.  553. 

(2)  De  medulla  spinali,  Gottingen,  1741,  § 12. 

(3)  Morgagni  (Ep.  anat.,  vol.  xvi.  8vo.)  also  says  : Septies  ab  eo  tempore  ex  quo 
semel  anteriores  tantam  reperi,  posteriores  illas  fibr as  quœsivi.  Bis  dubius  hœsi. 
Q uater  procvl  omni  dubio  nullas  omnino  fuisse  deprehendi.  Semel  a dextris.... 
sed  ne  in  eo  quidem  ipso....  ullam  prorsus  fibram  e sinistris. — See  also  Vicq-d’Azyr, 
Mém.  de  Paris,  1781,  p.  596. — Gordon,  p.  214. — Cloquet,  p.  631. 


OF  THE  NERVOUS  SYSTEM, 


35 


The  posterior  root  most  generally  anastomoses  with  the  accessory 
nerve.  This  is  sometimes,  although  more  rarely,  the  case  with  the 
anterior.  Sometimes  the  posterior  does  not  unite  with  the  anterior  ; it 
goes  only  to  the  accessory  nerve,  in  which  case  the  latter  after  forming 
a small  ganglion  which  however  does  not  constantly  exist,  sends  one 
or  two  filaments  to  the  anterior  root  of  the  second  cervical  nerve. 

Sometimes  instead  of  the  posterior  root  we  find  only  a plexus  which 
anastomoses  with  the  accessory  nerve,  the  filaments  of  which  go 
towards  the  opening  destined  for  the  passage  of  the  first  cervical 
nerve.(l). 

When  the  posterior  root  and  the  accessory  nerve  do  not  anastomose, 
we  generally  find  a filament  which  extends  from  this  root  to  the  pos- 
terior root  of  the  second  cervical  nerve  ; but  this  filament  is  not  con- 
stant. 

The  direction  of  the  first  cervical  nerve  is  most  generally  transverse 
from  its  origin  to  its  emerging  from  the  spinal  canal.  It  not  unfre- 
quently  proceeds  in  a direction  opposite  to  that  of  the  other  cervical 
nerves,  that  is,  it  proceeds  a little  more  from  below  upward  and  from 
within  outward  like  the  cerebral  nerves. 

The  superior  filaments  of  the  posterior  root  rarely  go  upward,  and 
the  inferior  downward.  Still  more  rarely  the  inferior  filaments  of  the 
two  roots  have  a direction  from  above  downward,  while  on  the  con- 
trary the  superior  commonly  follow  this  direction. 

It  is  easy  to  observe  that  the  smallness,  the  frequent  absence  and 
the  anterior  situation  of  the  posterior  root,  its  separation  from  the  an- 
terior, the  anastomosis  of  the  latter  with  the  accessory  or  the  second 
cervical  nerve,  and  the  direction  of  the  whole  nerve,  establish  a great 
analogy  between  the  latter  and  the  cerebral  nerves,  while  the  frequent 
existence  also  of  the  roots  and  their  place  of  origin,  establish  a 
resemblance  with  the  spinal  nerves. 

§ 1849.  The  trunk  of  the  first  cervical  nerve  passes  between  the 
occipital  portion  of  the  basilar  bone  and  the  transverse  process  of  the 
atlas,  in  the  lateral  groove  of  the  vertebra  below  the  vertebral  artery, 
after  forming  a very  elongated,  more  or  less  apparent,  and  often  almost 
imperceptible  ganglion.  It  divides,  as  usual,  opposite  the  posterior 
edge  of  the  atlas  into  an  anterior  and  a posterior  branch. 

The  posterior  is  larger,  and  proceeds  obliquely  backward  and  up- 
ward, and  divides  into  seven  or  eight  radiating  filaments  which  go  to 
the  obliquus  capitis  minor,  the  obliquus  capitis  major,  the  rectus 
capitis  major  and  minor,  and  the  complexus  muscles.  Some  pene- 
trate within  the  mastoid  process. 

The  anterior  is  smaller,  goes  first  from  behind  forward  along  the 
vertebral  artery  to  the  place  where  this  vessel  leaves  the  vertebral 
canal,  it  then  immediately  ascends  between  the  transverse  process  of 


(1)  Vicq-d’Azyr,  loc.  cit.,  p.  296. 


36 


DESCRIPTIVE  ANATOMY. 


the  atlas  and  the  mastoid  process.  It  then  divides  into  four  or  five 
branches. 

The  first  turns  around  on  the  transverse  process  of  the  atlas,  pro- 
ceeding from  above  downward,  and  anastomoses  with  one  or  two  as- 
cending filaments  of  the  anterior  branch  of  the  second  pair.  It  gives 
off  some  filaments  which  unite  with  the  pneumo-gastric,  the  hypo- 
glossal, and  the  great  sympathetic  nerve. 

The  second  goes  to  the  temporalis  muscle. 

The  third  enters  the  vertebral  canal,  is  distributed  to  the  vertebral 
artery,  and  sends  filaments  to  the  second  cervical  nerve. 

The  fourth  and  fifth  arise  before  the  transverse  process  of  the  first 
cervical  vertebra,  and  are  distributed  in  the  rectus  capitis  major  and 
minor  muscles. 

The  peculiarity  in  the  distribution  of  this  nerve,  is,  that  being  situ- 
ated very  deeply,  it  sends  off  filaments  only  to  these  muscles  and  these 
vessels,  and  does  not  extend  to  the  skin. 


CHAPTER  II. 

ENCEPHALIC  NERVES. 

§ 1850.  The  following  are  usually  mentioned  as  general  characters 
of  the  encephalic  nerves(l)  to  distinguish  them  from  the  spinal  nerves. 

1st.  They  arise  by  a single  root. 

2d.  On  leaving  the  dura-mater  they  do  not  produce  any  special 
ganglion  without  the  concurrence  of  another  nerve. 

3d.  They  pass  through  foramina  in  the  bones  of  the  skull,  or  through 
very  irregular  fissures  formed  in  them. 

4th.  They  expand  in  parts  other  than  the  muscles  of  the  skin,  par- 
ticularly in  the  organs  of  sense  and  the  viscera.  (2) 

But  of  all  these  characters  only  the  first  is  with  difficulty  of  general 
application.  The  fifth  pair  is  an  exception  to  the  second,  as  its  semi- 
lunar ganglion  is  formed  without  the  concurrence  of  any  other  nerve  : 
we  can  even  to  a certain  extent  mention  the  olfactory  nerve  in  this 
respect.  The  glosso-pharyngeal  and  the  pneumo-gastric  with  the  ac- 
cessory nerve,  also  produce  a considerable  ganglion  shortly  after 
leaving  the  cranium.  In  fact  , these  latter  unite  to  give  rise  to  the 
ganglion  : but  first,  the  anomaty  resulting  from  it  disappears,  when  it 
is  considered  that  these  three  nerves  should  be  regarded  as  forming  but 
one  : second,  almost  all  the  cervical  nerves  anastomose  with  each 

(1)  J.  D.  Santorini,  Obs.  anat .,  cap.  iii. — A.  Bergen,  Dé  nereis  quibusdam  cranii 
ad  novem  paria  hactenus  nun  rélalis,  Erfort,  1738.' — Morgagni,  Ep.  anal.,  xvi. — 
Sœmmerring,  De  basi  cncephali  et  originibus  nervorum  e cranio  egredienlium , 
Gottingen,  1778.— Id.,  Tabula  baseos  encepliali , Francfort,  1799. — Stieck,  De  quin- 
que  prioribus  encepliali  nereis , Gottingen,  1791. 

(2)  Huber,  De  medulla  spinali,  Gottingen,  1741,  p.  8,  9. — Ascii,  De  primo  pare 
mcdullœ  spinalis,  Gottingen,  1750,  §xxvii. 


OF  THE  NERVOU-S  SYSTEM. 


37 


other  within  the  dura-mater  by  intermediate  filaments,  before  that 
each  produces  its  ganglion.  As  to  the  third  character,  it  does  not 
depend  on  the  nerves,  but  only  on  the  difference  in  the  size  and  con- 
nections of  the  bones  of  the  skull  and  the  vertebrae.  Besides,  it  is  not 
so  exclusive  as  has  been  asserted,  since  we  not  only  sometimes  find 
an  opening  in  the  first  cervical  vertebra  for  the  first  cervical  nerve,  but 
also  the  sacral  nerves  constantly  pass  through  the  foramina  of  a bone 
originally  composed  of  several  pieces  immoveably  articulated  to- 
gether. In  animals  we  find  foramina  for  the  passage  of  the  corres- 
ponding cervical  nerves,  not  only  in  the  first  cervical  vertebra,  in  all 
the  mammalia  except  some  apes,  but  also  in  the  second,  but  even  in 
several  of  the  following  in  some  of  these  animals,  particularly  the 
hog. 

The  insufficiency  of  the  latter  character  seems  no  less  evident  when 
we  consider,  first,  that  the  spinal  nerves  necessarily  cannot  go  to 
parts  which  are  not  yet  formed  : second,  that  the  lumbar  and  sacral 
nerves  are  distributed  to  the  genital  and  urinary  organs,  and  also  to 
the  latter  portion  of  the  intestinal  canal. 

It  follows  then  that  the  distinction  between  the  spinal  and  the  ence- 
phalic nerves  is  not  so  well  marked  as  we  should  be  tempted  to  think 
at  first  view,  and  from  the  assertions  of  anatomists.  Far  from  it  : we 
shall  demonstrate  that  it  is  very  easy  to  refer  the  second  to  the  first, 
and  to  show  that  they  are  both  constructed  after  the  same  type. 

§ 1851.  We  have  already  mentioned  the  principal  differences  in 
authors  in  respect  to  the  number  of  the  encephalic  pairs  they  establish, 
and  demonstrated  that  they  depend  on  the  different  manner  of  bounding 
the  different  portions  of  the  centre  of  the  nervous  system.  But  there 
are  others  depending  on  the  fact,  that  some  cerebral  nerves  have  been 
regarded  sometimes  as  distinct  pairs,  sometimes  only  as  portions  of 
pairs.  . 

The  old  anatomists  followed  the  first  course,  while  the  moderns, 
adopting  the  second,  have  increased  the  number  of  cerebral  pairs, 
which  has  gradually  risen  from  seven  to  twelve,  and  even  according 
to  Malacarne,(l)  to  fifteen.(2) 

The  twelve  cerebral  nerves  most  generally  admitted  now,  are,  pro- 
ceeding from  behind  forward,  1st,  the  sublingual  ; 2d,  the  accessory  ; 
3d,  the  pneumo- gastric  ; 4th,  the  glosso-pharyngœal  ; 5th,  the  facial  ; 
6th,  the  auditory  ; 7th,  the  external  or  posterior  motor  ; 8th,  the  trifa- 
cial : 9th,  the  internal  or  superior  motor  ; 10th,  the  common  motor  ; 
11th,  the  optic  ; 12th,  the  olfactory  nerve. 

The  reasons  for  admitting  a smaller  number  of  nerves  are,  first,  the 
olfactory  nerve  was  long  considered,  till  the  time  of  Massa,  not  as  a 
nerve,  but  as  a portion  of  the  cerebrum  : second,  till  the  time  of  Achil- 
lini,  the  common  external  motor  nerve  of  the  eye  was  considered 
as  part  of  the  fifth  : third,  the  auditory  and  the  facial  nerves  have  been 

(1)  Neuro  -encephalotarnia,  Pavia,  1791. 

(2)  Malacarne  numbers,  properly  speaking',  seventeen  ; but  the  seventeenth  is  the 
posterior  root  of  the  suboccipital  nerve,  and  the  eleventh  the  sympathetic  nerve. 

Vol.  Ill  6 


38 


DESCRIPTIVE  ANATOMY. 


considered  as  one  till  the  time  of  Sœmmeriing  ; fourth  and  fifth, 
till  the  time  of  Andersch,  the  glosso-pharyngceal  and  the  accessory- 
nerves  have  been  considered  only  as  portions  of  the  pneumo-gastric 
nerve.  Certain  anatomists,  however,  and  even  before  the  preceding 
division  was  established  by  Scemmerring’s  publication,  had  considered 
a greater  or  less  number  of  the  nerves  mentioned,  as  distinct  pairs. 

Malacarne  states  the  number  of  the  encephalic  nerves  to  be  fifteen  : 
first  and  second,  by  admitting  an  accessory  nerve  to  the  common  motor 
and  to  the  superior  motor  nerve  ; third  and  fourth,  by  considering  the 
three  branches  of  the  trifacial  as  so  many  distinct  nerves,  which  would 
make  sixteen  pairs,  if  instead  of  distinguishing  the  glosso-pharyngceal, 
it  had  not  been  united  to  the  pneumo-gastric  nerve.  But  this  method 
is  very  objectionable,  for  even  when  Malacarne  had  cause  to  admit  his 
accessory  nerves  to  the  motors,  he  could  regard  them  only  as  the  roots 
of  these  latter,  to  the  trunks  of  which  they  unite  : second,  the  three 
branches  of  the  trifacial  nerve  arise  by  a common  nervous  trunk  : third, 
the  glosso-pharyngceal  nerve  deserves  to  be  separated  from  the  adja- 
cent nerves,  and  considered  as  a distinct  pair  more  than  any  which 
Malacarne  insulates. 

Farther,  we  shall  have  occasion  hereafter  to  show  that  it  would  be 
more  convenient  to  diminish  than  to  increase  the  number  of  cerebral 
nerves,  but  at  present  we  shall  follow  the  common  division. 

The  principle  of  the  nomenclature  of  the  nerves  is  not  the  same  in 
all.  Formerly  the  respective  situation  of  their  origin  was  taken  for 
them,  and  they  were  numbered  from  before  backward.  Still  later 
this  method  was  preserved,  but  names  drawn  from  their  distribu- 
tion and  their  uses  were  applied.  This  latter  mode  is  undoubtedly  the 
best,  and  we  follow  it  much  more  willingly,  because  the  first  does  not 
entirely  agree  with  our  mode  of  considering  the  nerves,  commencing 
at  the  spinal  marrow. 

§ 1852  The  cerebral  nerves  of  man  differ  considerably  in  respect  to 
volume,  form,  and  origin. 

1st.  Volume.  The  cerebral  nerves  generally  diminish  in  size  in  the 
following  older;,  the  trifacial,  the  optic,  the  olfactory,  the  auditory,  the 
common  motor,  the  pneumo-gastric,  the  glosso-pharyngceal,  the  facial, 
the  external  motor,  the  accessory,  the  hypoglossal,  and  the  superior 
motor. 

Form.  Here  we  may  consider, 

1st.  The  shape.  Most  of  these  nerves  are  round;  the  external  motor 
however  is  slightly  flattened,  and  the  olfactory  is  triangular. 

2d.  Texture.  Almost  all  are  fibrous  from  their  origin  ; in  the  olfactory 
nerve  alone  there  are  no  distinct  fibres.  In  some,  the  fibres  continue 
separate  longer  than  in  others,  and  they  are  the  more  so,  the  more  pos- 
terior the  origin  of  the  nerves.  They  generally  unite  in  fasciculi  of 
various  sizes  before  they  blend  in  one  trunk.  These  fasciculi  are  more 
numorous,  and  are  more  similar  in  size  the  more  posteriorly  the  nerves 
are  situated.  The  two  anterior  nerves  form  only  one  trunk  on  leaving 
the  cerebrum. 


OF  THE  NERVOUS  SYSTEM. 


39 


We  must  mention  here  the  differences  in  their  substance  and  solidity. 
The  eleven  posterior  cerebral  nerves  are  composed,  like  the  spinal 
nerves,  of  white  substance  ; the  olfactory,  on  the  contrary,  contains 
some  which  is  gray.  This  nerve  and  the  auditory  are  much  softer 
than  the  others. 

3d.  Origin.  In  this  respect, 

a.  The  cerebral  nerves  succeed  each  other  from  behind  forward. 

b.  All  arise  from  the  inferior  part  of  the  cerebrum.  Some,  particu- 
larly the  hypoglossal,  the  accessory,  the  pneumo-gastric,  the  glosso- 
pharyngeal, the  posterior  motor,  the  trifacial,  the  common  motor,  and 
the  olfactory,  come  from  its  lower  face.  The  others  arise  more  or  less 
from  its  upper  face. 

c.  The  origins  of  some,  as  the  trifacial  and  the  common  motor,  are 
deeply  concealed  in  the  substance  of  the  parts  of  the  cerebrum  from 
the  surface  of  which  they  emerge-.  On  the  contrary,  most  of  the  others 
cannot  be  traced  beyond  the  surface. 

4th.  Direction  and  progress.  All  go  forward  ; but  they  differ  from 
each  other  in  this  respect,  that  the  direction  of  the  posterior  ten  is  for- 
ward and  outward,  while  the  optic  nerve  proceeds  forward  and  inward 
at  its  posterior  part,  unites  with  that  of  the  opposite  side,  and  does  not 
go  outward  till  after  this  union.  The  course  of  the  olfactory  nerve 
is  obliquely  inward  and  forward. 

I.  HYPOGLOSSAL  NERVE. 

§ 1853.  The  hypoglossal  nerve,  hyoglossien,  Ch.  the  ninth  cerebral 
pair,  the  tivelfth  of  the  usual  method  ( JV.  lingualis  médius , Haller  ; 
gustalorius , Winslow  ; lingualis,  Vicq-d’Azyr  ; hypoglossus , Wins- 
low),^) arises  from  the  anterior  face  of  the  medulla  oblongata,  passes 
through  the  anterior  condyloid  foramen,  and  is  distributed  principally 
to  the  muscles  of  the  tongue. 

It  commences  by  several  fasciculi  placed  after  each  other  from  above 
downward.  These  fasciculi,  arranged  in  a single  series  about  half  an 
inch  long,  describe  a curved  line,  which  is  convex  outward,  as  the 
superior  and  inferior  are  placed  a little  farther  outward  than  the  central. 
They  come  from  the  groove  between  the  pyramid  and  the  olivary 
body.  The  inferior  arise  below  this  latter  eminence  ; the  superior 
begin  a little  above  the  centre  of  the  groove.  All  are  situated  a little 
farther  outward  than  the  anterior  roots  of  the  first  cervical  nerve,  the 
lowest  of  which  are  about  two  lines  distant  from  above  downward. 

The  whole  series  of  these  fasciculi  corresponds  with  much  exact- 
ness to  the  origin  of  the  glosso-phaijmgeal,  and  the  pneumogastric 
nerves,  and  to  that  portion  of  the  accessory  nerve  which  arises  from  the 
medulla  oblongata. 

(1)  J.  F.  G.  Bœhmer,  De  nono  pare  nervorum  cerebri,  Gottingen,  1777. — H.  F. 
Kilian,  Untersuchung  über  dus  neunte  Hirnnervenpaar , Perth,  1822. 


40 


DESCRIPTIVE  ANATOMY. 


They  are  always  very  distinctly  separated  from  each  other  at  their 
origin,  and  commence  by  several  radicles,  which  are  themselves  gene- 
rally composed  of  other  smaller  radicles. 

They  vary  in  their  number  and  situation.  We  admit  from  four  to 
eight  of  them.  They  usually  succeed  each  other  uninterruptedly,  so 
that  the  smallest  radicles  of  the  different  fasciculi  touch  each  other. 
Sometimes,  however,  we  observe  some  which  are  more  remote  from 
the  others,  and  even  about  a line  distant  from  them,  so  that  this  ar- 
rangement divides  them  into  two  or  three  bundles  of  different  sizes. 

These  fasciculi  reunite  in  cords  which  are  generally  two  and  some- 
times three  in  number,  each  of  which  passing  through  a special  open- 
ing in  the  dura-mater,  proceeds  from  behind  forward,  from  below  up- 
ward, and  from  within  outward,  towards  the  posterior  orifice  of  the 
anterior  condyloid  foramen.  They  rarely  unite  in  a single  trunk 
before  they  enter  the  dura-mater.  Sometimes  even  an  osseous  septum 
divides  them  for  the  whole  extent  of  the  condyloid  canal,  into  at  least 
two  halves,  which  unite  only  at  the  external  orifice  of  this  canal. 

On  leaving  the  cranium  the  trunk  goes  downward,  proceeding  on 
the  upper  part  of  the  condyle,  and  covered  outward  in  the  extent  of 
about  an  inch,  by  that  of  the  pneumo-gastric  nerve,  with  which  it  is 
generally  united  by  filaments,  it  passes  on  the  internal  carotid  artery, 
and  descends  from  behind  forward  between  the  laryngœal  branch  of 
the  pneumo-gastric  and  the  accessory  nerve. 

In  this  place  it  unites  at  first  near  the  summit  of  the  transverse 
process  of  the  first  cervical  vertebra  forward  and  upward  by  a con- 
siderable filament,  with  the  pneumo-gastric  nerve  downward  and 
backward,  with  the  first  cervical  nerve  and  the  great  sympathetic 
nerve  by  another  filament  which  ascends  from  the  anterior  branch  of 
the  first,  and  from  the  superior  cervical  ganglion,  before  which  it  is 
situated.  It  then  descends,  covered  outward  by  the  pneumo-gastric 
nerve,  the  posterior  belly  of  the  digastricus  muscle,  the  stylo-glossus 
muscle,  and  the  internal  jugular  vein,  inward  by  the  internal  carotid 
artery,  and  gives  ramifications  to  the  submaxillary  gland.  When  as 
high  as  the  third  cervical  vertebra,  it  passes  before  the  external  carotid 
artery,  and  forming  a large  arch,  which  is  convex  downward,  it  goes 
from  behind  forward  and  from  below  upward,  towards  the  genio-glossus 
muscle,  along  the  inside  of  the  posterior  and  inferior  hyoid  bone. 

At  the  origin  of  its  arch  it  gives  off  a considerable  and  very  con- 
stant branch,  the  descending  serviced  nerve  (R.  descendons  noni ), 
which  goes  downward  and  forward,  first  along  the  anterior  face  of  the 
external  carotid  artery,  where  it  is  intimately  united  to  the  trunk  of 
the  pneumo-gastric  nerve  by  cellular  tissue,  then  to  the  inner  side  of 
the  internal  jugular  vein,  passes  above  the  superior  thyroid  artery, 
goes  still  farther  forward  on  leaving  this  point,  gives  off  forward  and 
inward  a branch  which  terminates  in  the  anterior  belly  of  the  omo- 
hyoideus  muscle,  sends  others  to  the  muscles  of  the  larynx,  and  again 
uniting  in  the  middle  of  the  neck  with  the  descending  nerve  which 
comes  from  the  anterior  branches  of  the  second  and  third  cervical 


OF  THE  NERVOUS  SYSTEM. 


41 


nerves,  thus  forms  an  arch,  the  convexity  of  which  is  well  marked  and 
turned  forward. 

The  convexity  of  this  arch  usually  gives  rise  to  two  branches,  which 
descend  along  the  anterior  side  of  the  internal  jugular  vein.  The 
superior  is  smaller,  and  retrogrades  to  go  to  the  anterior  belly  of  the 
omo-hyoideus  muscle.  The  inferior  is  larger,  passes  under  the  anterior 
belly  of  this  muscle,  goes  downward  and  forward  to  the  external  face 
of  the  sterno-thyroideus  muscle,  distributes  several  filaments  in  this 
muscle  and  the  sterno-hyoideus  muscle,  and  anastomoses  in  this  place 
by  a small  but  constant  filament,  with  the  diaphragmatic  nerve.  Some 
ramifications  of  this  branch  enter  the  chest,  particularly  on  the  left 
side,  and  extend  to  the  upper  part  of  the  pericardium. 

The  trunk  of  the  hypoglossal  nerve  immediately  gives  off  some 
branches  which  go  downward  into  the  thyro-hyoideus  muscle.  Thence 
it  rises  again,  first  below  the  tendon  of  the  digastricus  muscle,  then  on 
the  external  face  of  the  hyoglossus  muscle,  gives  filaments,  of  which 
the  upper  anastomose  frequently  from  its  upper  and  lower  parts,  but 
principally  from  this  latter  to  the  muscles  of  the  larynx,  then  to  the 
hyoglossus,  to  the  genio-hyoideus,  and  to  the  genio-glossus  muscle, 
unites  with  the  lingual  nerve  of  the  third  branch  of  the  trifacial  in  the 
upper  and  anterior  part  of  the  hyoglossus  muscle,  by  two  or  three  con- 
siderable filaments,  and  afterwards  extends  almost  to  the  point  of  the 
tongue  by  ramifications  which  proceed  between  the  fibres  of  the  hyo- 
glossus muscle. 

At  the  body  of  the  hyoid  bone  the  trunk  of  the  nerve  turns  on  the 
lingual  artery,,  and  enters  the  genio-glossus  muscle,  in  which  it  ter- 
minates by  branches,  some  of  which  go  to  the  lower  face  of  the  point 
of  the  tongue. 

We  cannot  follow  the  filaments  of  the  hypoglossal  nerve  into  the 
integuments  of  the  tongue  ; they  stop  in  the  muscles  of  this  organ. 
From  this  circumstance  we  might  deduce  the  very  probable  conclusion 
that  it  serves  only  to  excite  the  motions  of  the  muscles,  and  that  it  is 
not  the  proper  gustatory  nerve,  although  it  communicates  by  very 
large  anastomoses  with  the  lingual  branch  of  the  trifacial  nerve,  the 
ramifications  of  which  penetrate  distinctly  into  the  integuments  of  the 
tongue.  Another  circumstance  gives  more  weight  to  this  conjecture, 
viz.  the  analogy  between  it  and  the  motory  nerves  of  the  other  organs 
of  the  senses  which  receive  both  nerves  of  sensation  and  of  motion. 
That  these  two  orders  of  nerves  fulfill  different  functions,  is  demon- 
strated by  the  observation,  that  alterations,  the  primitive  or  accidental 
destruction  of  one  of  them,  is  attended  only  with  the  loss  of  one  of  the 
two  faculties  of  the  tongue,  that  of  the  taste  when  the  affection  is 
situated  in  the  lingual  branch  of  the  trifacial  nerve,  and  that  of  motility 
when  the  hypoglossal  nerve  is  affected.(l)  The  loss  of  taste  in  one 


(1)  The  sense  of  taste  is  lost  in  trisma,  but  the  levator  muscles  of  the  lower  jaw 
receive  their  nerves  from  the  fifth  pair  and  not  from  the  hypoglossal  nerve  (HaÜer, 
El.phys .,  vol.  v.  p.  112).  The  congenital  absence  of  taste  has  been  observed  in  a 
patient  where  the  lingual  branch  went  to  the  occiput  and  not  to  the  tongue  (Colombo, 
De  re  anat.,  Paris,  1762,  p.  486.) 


42 


DESCRIPTIVE  ANATOMY. 


case  where  the  hypoglossal  nerve  was  injured(l)  even  when  this 
lesion  would  not  have  been  admitted  as  probable,  would  not  prove 
that  the  two  nerves  concurred  in  the  function  of  taste,  for  on  one  side 
the  lesion  might  produce  this  effect  only  from  the  connections  between 
the  two  nerves  ; and  secondly  a case  cited  by  Heuermann  would 
farther  prove  that  it  cannot  be  admitted,  since  on  account  of  the  distri- 
bution of  the  hypoglossal  nerve  and  of  the  lingual  branch  of  the 
trifacial  nerve,  the  hypoglossal  nerve  could  not  alone  be  the  nerve  of 
taste,  as  should  be  concluded  from  this  fact,  considered  as  a peremp- 
tory argument  in  favor  of  the  power  attributed  by  the  author  to  the 
nervous  trunk  supposed  to  be  injured. 

But  the  difference  of  function  between  the  two  nerves  is  not  proved 
by  the  cases  where  the  loss  of  the  motion  of  the  tongue  without  that 
of  taste,  or  the  loss  of  taste  without  that  of  the  motion  of  the  tongue(2) 
in  general,  have  been  observed,  since  the  same  phenomenon  is  seen 
in  other  parts  which  receive  only  one  nerve,  and  which  cannot  conse- 
quently be  explained  in  the  same  manner. 

II.  ACCESSORY  NERVE. 

§ 1854.  The  accessory  nerve, (3)  trachelo  dorsal , Ch.  (JY.  spinalis 
ad  par  vagum  accessorius , accessorius  Willisii),(4)  arises  by  numerous 
filaments  from  the  posterior  part  of  the  lateral  face  of  the  posterior  cord 
of  the  spinal  marrow,  ascends  between  the  posterior  roots  of  the  upper 
six  cervical  nerves  and  the  ligamentum  denticulatum,  nearer  the  for- 
mer than  the  latter,  consequently  also  nearer  the  posterior  than  the 
anterior  roots  of  the  cervical  nerves,  penetrates  into  the  skull  through 
the  occipital  foramen  behind  the  vertebral  artery,  receives  some  fila- 
ments from  the  latter  parts  of  the  medulla  oblongata,  is  situated  below 
near  the  pneumo -gastric  nerve,  with  which  it  emerges  from  the  skull 
through  the  posterior  foramen  lacerum,  and  is  distributed  partly  in 
the  upper  region  of  the  pharynx,  partly  also  in  some  muscles  of  the 
back. 

Its  lowest  and  smallest  root  usually  arises  at  the  height  of  the  supe- 
rior filament  of  the  posterior  roots  of  the  seventh  cervical  pair  ; the 
second  at  that  of  the  upper  part  of  the  posterior  root  of  the  fifth  ; the 
third  and  fourth  at  that  of  the  upper  part  of  the  fourth  ; the  fifth  oppo- 
site that  of  the  third  ; the  sixth  between  the  second  and  third  ; and  the 
seventh  opposite  the  posterior  root  of  the  second.  Many  of  these  roots 

(1)  Heuermann,  .Physiologie,  vol.  ii.  p.295. 

(2)  Sœmmerring,  Nervenlehre,  p.  262. — Scarpa,  Tab.  neurol.,  Pavia,  1794,  p. 
16-17.  Two  cases. 

(3)  Often  termed  the  accessory  nerve  of  Willis , but  wrongly,  as  it  had  previously 
been  figured  by  Eustachius  and  described  by  Coiter. 

(4)  J.  P.  Lobstein,  De  nervo  spinali  ad  par  vagum  accessorio,  Strasburg,  1760. — 
A.  Scarpa,  Uber  den  zum  achten  Paare  der  Gehirnnerven  hinlaufenden  Beinerven 
des  Rückenmarncs  ; in  the  Abhandl.  der  Josephsakad,  vol.  i.  p.  385. — Its  origin  has 
been  described  perfectly  by  Huber,  De  medulla  spinali , specialim  de  nervis  ab  eâ 
provenientibus,  Gottingen,  1741,  § vii-xi. 


OF  THE  NERVOUS  SYSTEM. 


43 


sometimes  communicate  in  one  or  several  points  with  the  anastomotic 
filaments  of  the  middle  and  superior  cervical  pairs. 

Usually  no  root  of  the  accessory  nerve  arises  from  a higher  point  of 
the  spinal  marrow. 

Sometimes,  however,  the  whole  posterior  root  of  the  first  cervical 
nerve  joins  it  and  forms  with  it  a small  ganglion.  But  this  ganglion 
is  not  constant  when  the  nerves  unite,  and  we  should  even  think  it 
extremely  rare,  since  it  has  never  been  observed  by  Haller,  Ash, 
Lobstein,  and  Scarpa,  who  have  remarked  only  a slight  thickening  of 
the  nerve. (1)  We  have  never  seen  it  but  a few  times,  notwithstanding 
our  numerous  researches. 

Three  or  four  roots  generally  arise  within  the  skull  from  the  lateral 
face  of  the  posterior  cord  of  the  medulla  oblongata  ; these  are  behind 
the  roots  of  the  hypoglossal  nerve. 

These  ten  or  eleven  roots  gradually  become  longer  and  thicker 
from  below  upward,  and  go  towards  the  trunk  of  the  nerve  at  angles 
which  are  more  acute  the  lower  their  origins.  The  lowest  is  in  great 
part  concealed  in  the  pia-mater,  through  which  it  only  penetrates. 
The  spinal  roots  also  are  usually  single,  while  those  arising  from  the 
medulla  oblongata  are  generally  composed  of  two  short  radicles  united 
at  an  acute  angle,  each  of  which  is  formed  by  three  or  four  filaments. 
These  radicles,  one  of  which  is  superior,  the  other  inferior,  and  the  se- 
cond of  which  ascends  in  a more  perpendicular  direction,  soon  reunite. 
In  considering  the  whole  series  of  roots,  we  recognize  that  they  gra- 
dually become  more  anterior  from  below  upward. 

The  nerve  enlarges  as  it  ascends,  goes  imperceptibly  outward,  and 
is  attached  above  by  short  filaments  to  the  trunk  of  the  pneumo-gastric 
nerve. 

The  accessory  nerve  never  arises  lower  than  the  point  indicated. 
On  the  contrary  it  often  commences  higher,  opposite  the  sixth  cervical 
vertebra,  sometimes  even  but  more  rarely  opposite  the  fifth.  In  some 
subjects  it  receives  from  the  spinal  marrow  only  two  or  three  roots, 
which  are  then  proportionally  thicker. 

The  number  of  the  filaments  from  the  medulla  oblongata  is  some- 
times less  than  we  have  mentioned  : it  is  rarely  and  perhaps  never 
greater.  Sometimes  they  resemble  by  being  single  those  which  arise 
from  the  spinal  marrow. 

So  likewise  the  accessory  nerve  does  not  always  arise  exactly  in  the 
same  place. 

It  is  very  rarely  united  by  a filament  with  the  posterior  root  of  the 
second  cervical  nerve. (2) 

It  does  not  anastomose  with  the  hypoglossal  nerve  within  the 
skull.  (3) 

(1)  Scarpa,  loc.  cit.,  p.  396. 

(2)  Scarpa,  loc.  cit.,  p.  395.  This  anatomist  has  observed  this  union  only  twice  in 
his  numerous  dissections  We  have  found  it  only  once. 

(3)  Scarpa,  loc.  cit.,  p.  397,  does  not  admit  this  assertion  of  Winslow.  We  have 
never  seen  the  anastomosis  mentioned  by  this  latter. 


44 


DESCRIPTIVE  ANATOMY. 


It  generally  passes  through  the  dura-mater  in  connection  with  the 
pneumo-gastric  nerve  : but  sometimes  also  it  emerges  through  a spe- 
cial opening  behind  the  latter,  with  which  however  it  reunites. 

All  these  differences  are  observed  not  only  in  different  persons,  but 
frequently  in  the  same  person  on  different  sides  of  the  body. 

In  passing  through  the  dura-mater  the  accessory  nerve  is  inclosed  in 
a sheath  with  the  pneumo-gastric  nerve  ; but  before  emerging  through 
the  posterior  foramen  lacer  um  it  divides  into  an  internal  and  an  ex- 
ternal branch. 

The  internal  branch  gives  off  first  two  branches  which  unite  with 
each  other  and  with  a third  which  descends  from  the  pneumo-gastric 
nerve,  and  produces  the  superior  pharyngœal  nerve.  It  then  receives 
some  filaments  from  the  pneumo-gastric  nerve,  sometimes  communi- 
cates with  the  hypoglossal  nerve,  then  reunites  with  the  trunk  of  the 
pneumo-gastric  nerve  to  form  a ganglion. 

The  external  branch  proceeds  for  about  two  inches  descending 
deeply  behind  the  internal  jugular  vein,  at  first  between  this  vessel  and 
the  occipital  artery,  then  between  it  and  the  sterno-cleido-mastoideus 
muscle.  It  turns  a little  on  this  muscle  and  goes  forward,  sometimes 
passes  through  it,  gives  to  it  filaments  which  anastomose  with  those 
of  the  third  cervical  nerve,  then  continues  to  descend  but  from  before 
backward,  passing  on  the  internal  jugular  vein,  enlarges  considerably 
by  uniting  with  two  anastomosing  branches,  the  upper  of  which  arises 
from  the  anterior  branch  of  the  second'  cervical  nerve  and  the  lower 
from  that  of  the  third,  passes  on  the  levator  anguli  scapulae  muscle, 
anastomoses  with  the  ramifications  of  the  fourth  and  fifth  cervical 
nerves,  and  comes  to  the  internal  face  of  the  trapezius,  in  which  it  is 
distributed.  No  other  muscles  receive  filaments  from  it. 

III.  PNEUMO-GASTRIC  NERVE. 

§ 1855.  The  pneumo-gastric , the  par  vagum , the  middle  sympa- 
thetic, the  pulmonary , the  vocal  nerve,  the  eighth,  or  according  to  the 
new  calculation,  the  tenth  pair  (JV.  pneumo gastricus,  Chaussier  ; JV. 
vagus,  JY.  sympathicus  médius,  Winslow;  JV.  pulmonalis , Bartels  ;(1) 
par  octavum,  Willis  ;(2)  decimum,  Andersch),(3)  arises  from  the 
side  of  the  posterior  prolongation  of  the  cerebellum  between  the  acces- 
sory and  the  glosso-pharyngœal  nerves,  emerges  from  the  skull 
through  the  posterior  foramen  lacerum,  and  descending  is  distributed 

(1)  Respiration , p.  210. 

(2)  This  term,  however,  includes  the  following'  or  the  glosso-pharyngeal  nerve. 

(3)  Neubauer,  Descript,  nerv.  cardiac. — Andcrsch,  in  the  Nov.  comm.  Gott.  vol.  ii. 
published  in  Haase,  Cerebri  nervorumque  anal.,  Leipsic,  1781,  and  in  Ludwig, 
Script,  neural,  min.  vol.  ii. — Walter,  De  nerv,  abdom.,  Berlin,  1800.— Wrisberg,  Da 
gonglio  plexuque  semilunari,  &c.  sect,  ii.,  De  pari  octavo  ; in  the  same  Comment. 
vol.  i.  1800. — Scarpa,  Tab.  neurolog.,  Pavia,  1794. 


OP  THE  NERVOUS  SYSTEM, 


45 


in  the  upper  part  of  the  alimentary  canal,  the  stomach  ; second  in  the 
organs  of  respiration  ; hence  the  term  pneumo-gastric. 

§ 1856,  It  arises  by  from  ten  to  sixteen  filaments  from  the  lower 
part  of  the  lateral  face  of  the  posterior  prolongations  of  the  cerebellum. 
The  inférior  are  situated  far  behind  the  anterior,  and  form  a series 
which  is  generally  single  and  five  or  six  lines  long.  Sometimes,  how- 
ever, several  are  more  anterior  than  the  others  ;(1)  this  is  particularly 
the  case  with  those  at  the  top  of  the  series,  although  there  is  no  dis- 
position indicating  any  tendency  to  produce  distinct  roots.  On  the 
contrary,  in  this  formation  the  pneumo-gastric  nerve  is  similar  to 
the  formation  of  the  anterior  cerebral  nerves,  as  its  origin  is  thus  more 
rounded,  which  form  is  remarkable  in  several  of  the  mammalia,  parti- 
cularly the  ruminantia.  These  filaments  arise  principally  towards  the 
anterior  and  inferior  edge  of  the  posterior  prolongation  of  the  cerebel- 
lum, in  the  groove  between  this  prolongation  and  the  olivary  body. 
They  do  not  extend  so  high  as  this  latter,  and  terminate  below  long 
before  those  of  the  hypoglossal  nerve.  Some  of  them  frequently  anas- 
tomose with  the  transverse  medullary  striae  on  the  floor  of  the  calamus 
scriptorius,  and  hence  these  striae  seem  to  concur  in  their  formation. (3) 
Others,  particularly  some  of  the  inferior,  come  from  the  lower  extremity 
of  the  olivary  body. (4) 

These  filaments  are  generally  single,  and  not  cleft  at  their  internal 
part.  They  are  sometimes  separated  and  sometimes  united  from  their 
origin  in  three  or  four  fasciculi.  The  inferior  are  commonly  very  inti- 
mately connected  with  the  accessory  nerve.  The  superior  most  gene- 
rally communicate  by  a transverse  filament  with  the  glosso-pharyngceal 
nerve  even  within  the  skull. 

These  filaments  and  fasciculi  unite  in  a flattened  trunk  about  one 
line  and  a half  broad,  one  quarter  or  one  fifth  of  a line  thick,  and  al- 
ways larger  at  its  upper  part  where  they  are  interlaced  with  each 
other.  This  trunk  goes  outward  and  backward.  It  is  inclosed  in  a 
small  canal  of  the  dura-mater,  through  which  it  comes  from  the  cranium, 
through  the  anterior  part  of  the  foramen  lacerum,  before  the  origin  of 
the  internal  jugular  vein.  It  is  separated  from  this  vein  by  a promi- 
nence of  bone  which  comes  from  the  petrous  portion  of  the  temporal 
bone  or  from  the  occipital  bone,  or  from  both,  and  from  the  accessory 
and  the  glosso-pharyngceal  nerves  by  the  dura-mater. 

The  fasciculi  hitherto  distinct  do  not  entirely  unite  in  a rounded 
cord  except  within  this  canal.  The  rounded  cord  on  leaving  the  fora- 
men lacerum  is  united  very  intimately  by  mucous  tissue  with  the 


(1)  Coopmans,  Neurol.,  p.  118. — Soemmerringr,  p.  102. 

(2)  Santorini,  Septemdecim  tabulae , p.  27. — Girardi,  ibid.— Vicq-d’Azyr,  in  the 
Mém.  de  Paris , 1784,  p.  594. 

(3)  Desmoulins,  Sur  le  rapport  qui  unit  le  développement  du  nerf  pneumogas- 
trique à celui  des  parois  du  quatrième  ventricule  ; in  the  Journ.  de  phys.  expérimen- 
tale, vol.  iii.,  p.  362. 

(4)  Vicq-d’Azyr,  loc.  cit.,  p.  594. 


46 


DESCRIPTIVE  ANATOMY. 


glosso-pharyngœal  nerve,  the  hypoglossal  and  the  ascending  branch  of 
the  superior  cervical  ganglion.  It  is  situated  at  first  behind  the  glosso- 
pharyngœal  and  before  the  hypoglossal  nerve,  but  it  soon  passes  be- 
hind this  latter,  is  separated  from  the  glosso-pharyngceal  nerve  by  the 
internal  jugular  vein,  leaves  the  hypoglossal  nerve  on  the  transverse 
process  of  the  first  cervical  vertebra,  and  descends  outward  and  a little 
backward  before  the  primitive  carotid  artery,  between  it  and  the  in- 
ternal jugular  vein,  intimately  united  to  these  two  vessels  by  a mucous 
tissue  destitute  of  fat  and  more  loosely  connected  to  the  intermediate 
filaments  of  the  sympathetic  nerve  which  are  situated  behind  it  and 
placed  in  the  rectus  capitis  major  anticus  and  the  longus  colli  mus- 
cles.(l) 

In  passing  through  the  foramen  lacerum  the  pneumo-gastric  nerve 
anastomoses  by  some  filaments  with  the  accessory  nerve,  and  shortly 
after  leaving  this  opening  it  communicates  also  with  the  glosso-pharyn- 
goeal  nerve  and  the  superior  cervical  ganglion.  It  then  gives  off  a 
branch  which  unites  with  two  filaments  from  the  inner  branch  of  the 
accessory  nerve,  and  gives  rise  to  the  pharyngœal  or  superior  pharyn- 
gœal nerve  (JY.  pliaryngœus,  s.  pliaryngœus  superior , s.  primus.) 

This  nerve  goes  obliquely  from  above  downward  and  from  without 
inward  on  the  inside  of  the  internal  carotid  artery,  sends  an  anasto- 
mosing filament  to  the  glosso-pharyngœal  nerve,  bulges  a little,  and 
forms  at  the  height  of  the  middle  constrictor  of  the  pharynx  a consi- 
derable plexus  termed  the  pharyngœal  ( plexus  pliaryngœus).  This 
plexus  receives  filaments  from  the  laryngceal,  the  glosso-pharyngœal 
nerves,  and  from  the  superior  cervical  ganglion  ; its  filaments  are  dis- 
tributed principally  in  the  middle  constrictor,  but  some  go  to  the  upper 
constrictor  of  the  pharynx  : a few  descend  along  the  primitive  carotid 
artery,  where  they  anastomose  with  the  ramifications  of  the  glosso- 
pharyngœal  and  the  superficial  cardiac  nerves. 

The  inferior  pharyngœal  nerve  (JY.  pliaryngœus  inferior , s.  minor), 
which  also  is  not  constant,  arises  directly  below  the  superior  pharyn- 
gœal nerve.  This  nerve  soon  anastomoses  with  the  preceding,  and 
also  with  one  or  several  of  the  anterior  filaments  of  the  superior  cer- 
vical ganglion,  sends  filaments  to  the  pharyngœal  plexus,  and  is  dis- 
tributed in  the  middle  constrictor  of  the  pharynx. 

At  the  place  where  the  pharyngœal  nerves  are  given  off  and  some- 
times also  a little  higher,  the  trunk  of  the  pneumo-gastric  nerve  be- 
comes much  thicker  and  its  texture  is  closer  for  about  an  inch  : its 
fasciculi  separate  very  much,  and  a reddish  gelatinous  substance  is 
deposited  between  them.  A real  ganglionnary  plexus  then  forms.  The 
remnant  of  the  internal  branch  of  the  accessory  nerve  after  sending  an 
anastomotic  twig  to  the  pharyngœal  nerve  enters  this  plexus  at  about 
its  centre,  sometimes  in  one  branch,  sometimes  also  in  several  filaments 
which  ramify  and  interlace  differently,  so  that  this  branch  forms  the 

(1)  J.  H.  Haase,  De  nervo  phrenico  dex'lri  lateris  duplki  par  isque  vagi  per  collum 
decursu,  Leipsic,  1790. 


OF  THE  NERVOUS  SYSTEM, 


47 


lower  part  of  the  plexus,  and  seems  also  to  belong  to  the  pneumo-gas- 
trie  nerve. 

The  trunk  of  the  pneûmo-gastric  nerve  is  in  fact  directly  attached  to 
this  ganglion  from  before  backward  ; but  it  is  sometimes,  although 
rarely,  connected  with  it  only  by  some  filaments  of  communication. 

A more  distinct  development  of  this  plexiform  dilatation  of  the  nerve 
occurs  when  it  divides  into  two  portions  which  unite  only  at  the  lower 
part  of  the  neck  ; but  such  an  arrangement  is  extremely  rare  : it  has 
been  observed  only  once  in  five  hundred  cases,  and  this  was  on  the 
right  side.(l) 

The  superior  laryngœal  nerve  (JY.  laryngœus  superior ),  which  is 
commonly  larger  than  the  inferior,  usually  arises  from  the  upper  part 
of  this  ganglion. 

This  nerve  descends  between  the  internal  carotid  artery  and  the  su- 
perior cervical  ganglion,  most  generally  anastomoses  by  one  or  several 
filaments  with  this  latter,  the  pharyngeeal  plexus,  and  the  hypoglossal 
nerve,  and  divides  into  an  external  and  an  internal  branch. 

The  external  goes  inward,  and  sends  filaments  to  the  inferior  con- 
strictor muscle  of  the  pharynx,  the  crico-thyroideus,  the  sterno-thy- 
roideus,  and  the  hyo-thyroideus  muscles,  to  the  thyroid  gland,  and  to 
the  membrane  of  the  pharynx  ; these  filaments  enter  the  cavity  of  the 
larynx  between  the  cricoid  and  thyroid  cartilages. 

The  internal  branch  passes  through  the  hyo-thyroid  membrane  be- 
tween the  hyoid  bone  and  the  thyroid  cartilage.  It  distributes  soft 
and  thick  filaments  in  the  membrane  and  glands  of  the  epiglottis,  the 
mucous  membranes  of  the  pharynx  and  larynx,  several  small  muscles 
of  the  larynx,  particularly  the  arytenoideus  and  the  crico-thyroideus, 
and  anastomoses  with  the  filaments  of  the  inferior  and  recurrent  laryn- 
gœal nerve. 

After  the  superior  laryngœal  nerve,  we  see  arise  either  from  the 
ganglionnary  plexus  or  directly  below  it  some  filaments  which  are  not 
constant  ; these  unite  to  the  descending  branch  of  the  hypoglossal 
nerve,  and  also  to  the  first  cervical  nerve,  and  to  the  soft  nerves  which 
go  to  the  internal  carotid  artery. 

After  giving  off  these  branches,  the  trunk  of  the  pneumo-gastric 
nerve  becomes  more  compact,  and  descends  in  the  manner  mentioned 
above,  but  gives  off  no  ramifications.  It  then  represents  a cord  com- 
posed of  less  distinct  fasciculi  and  which  is  generally  uneven  by  a kind 
of  indentation,  but  its  surface  is  surrounded  here  and  there  by  very 
minute  filaments  which  interlace  like  a plexus. (2)  It  gives  off  about 
an  inch  or  an  inch  and  a half  above  the  origin  of  the  primitive  carotid 
artery  (but  an  inch  higher  on  the  right  than  on  the  left  side),  and 
at  about  the  centre  of  the  neck,  on  both  sides,  the  cardiac  nerves  (R. 
cardiaci).  These  descend  from  within  outward  and  from  behind  for- 

(1)  Wrisberg,  De  nervis  pharyngis  ; in  Ludwig,  toc.  cit.,  vol.  iii.,  p.  57. 

(2)  Prochaska,  De  struc.  nerv.,  tab.  ii.,  fig.  7,  7,  ee. — Reil,  De  struct,  nerv.,  tab.  i., 
fig.  2,  3,  4. 


48 


DESCRIPTIVE  ANATOMY, 


ward  in  the  carotid  artery  and  the  innominata  trunk,  anastomose  with 
the  superficial  cardiac  nerves,  and  are  distributed  to  the  arch  of  the 
aorta.  We  generally  find  three  or  four  on  the  right  side,  the  upper  of 
which  is  the  largest  and  most  constant.  There  are  one  or  two  on  the 
left  side. 

The  trunk  of  the  pneumo-gastric  nerve  goes  forward,  is  situated 
behind  the  innominata  vein,  passing  on  the  right  before  the  subclavian 
artery,  on  the  left  before  the  arch  of  the  aorta,  thus  comes  into  the 
chest,  enlarges  considerably,  and  divides  into  two  halves,  of  which  the 
lower  and  larger  is  the  continuation  of  the  trunk,  and  the  upper  is 
smaller,  and  is  termed  the  inferior  laryngœal  ascending  or  recurrent 
nerve,  tracheal,  Ch.  (JV.  recurrens , s.  adscendens,  s.  laryngeus  in- 
ferior). 

The  two  recurrent  nerves  arise  within  the  chest,  the  left  much 
lower  than  that  of  the  right  side.  They  ascend  first  from  before  back- 
ward, then  vertically,  send  some  filaments  to  the  cardiac  nerves  which 
come  from  the  pneumo-gastric,  the  middle  and  inferior  cardiac  nerves 
which  come  from  the  ganglionnary  nerves,  form  with  them  a plexus, 
then  turn  from  before  backward,  the  right  on  the  right  subclavian 
artery,  the  left  on  the  extremity  of  the  arch  of  the  aorta,  and  are 
placed  behind  the  primitive  carotid  and  inferior  thyroid  artery,  between 
the  trachea  and  the  esophagus,  and  rise  to  the  larynx.  In  this 
course  they  give  off  first  the  branches  called  the  superior  tracheal 
nerves  (R.  tracheales  superiores),  which  descend  before  the  trachea 
and  anastomose  with  the  preceding,  arrive  at  the  bronchia  and  the 
pulmonary  plexus  of  their  side,  are  distributed  in  the  membrane  of  the 
trachea,  the  pharynx,  and  the  thyroid  gland,  and  communicate  with 
some  filaments  of  the  cervical  portion  of  the  sympathetic  nerve. 

Finally,  when  as  high  as  the  larynx  the  recurrent  nerve  is  distri- 
buted in  the  inferior  constrictor  of  the  pharynx  and  the  cricoarytenoid 
muscles,  enters  the  cavity  of  the  larynx  between  the  cricoid  and 
thyroid  cartilages,  and  terminates  in  the  thyroid  cartilage,  the  arytenoid 
muscle,  and  the  mucous  membrane  of  the  larynx,  by  anastomosing 
by  several  branches  with  the  superior  laryngœal  nerve. 

The  recurrent  nerve  is  sometimes  double,  but  this  is  rare,  and  when 
it  occurs  it  is  always  on  the  right  side,  if  we  judge  from  observations 
made  hitherto.  The  unusual  nerve  is  smaller  than  the  other,  and 
arises  from  the  trunk  some  lines  below  it,  turns  like  it  on  the  sub- 
clavian artery,  ascends  between  the  esophagus  and  the  trachea,  anas- 
tomoses by  a large  twig  with  the  normal  recurrent  nerve,  and  is  dis- 
tributed with  the  latter.(l) 

This  anomaly  seems  to  indicate  an  effort  to  establish  a perfect  simi- 
larity between  the  right  and  left  sides,  since  the  recurrent  nerve 
always  arises  lower  than  that  of  the  right  side. 

It  is  very  probable  that  the  recurrent  nerve  results  from  the  plexi- 
form division  of  the  trunk  of  the  pneumo-gastric,  and  that  its  existence 

(1)  Wrisberg'j  De  nervis  abdominis,  Gottingen,  1780. 


OF  THF  NERVOUS  SYSTEM. 


49 


is  connected  with  the  primitive  shortness  of  the  neck,  since  the  larynx 
is  much  nearer  its  origin  in  the  early  periods  of  life  than  subsequently. 
This  hypothesis  would  explain  its  arrangement  in  the  same  manner 
as  the  high  origin  and  long  course  of  the  spermatic  vessels.  Farther, 
it  is  impossible  to  deny  the  analogy  between  the  distribution  of  the 
nerves  and  vessels  in  this  region  of  the  body,  since  the  superior  and 
inferior  laryngoeal  nerves  and  the  superior  and  inferior  thyroid  arteries 
manifestly  correspond. 

§ 1857.  The  trunk  of  the  pneumo-gastric  nerve  having  given  off 
the  recurrent  nerve,  goes  backward  on  the  posterior  face  of  the  trachea. 

There  it  supplies  first  five  or  six  inferior  tracheal  nerves  ( V.  tra- 
chéales inferiores ),  some  of  which  proceed  before,  others  behind  the 
trachea.  The  former  anastomose  with  the  filaments  of  the  superior 
tracheal  nerves  and  with  others  coming  from  the  inferior  cervical 
ganglion.  Some  descend  before  on  the  ramifications  of  the  bronchiæ 
and  of  the  pulmonary  artery.  Others  enter  the  muscular  and  mucous 
tunics  of  the  trachea,  bronchia,  and  esophagus,  and  terminate  in  the 
pulmonary  plexus  {plexus  pulmonalis ) . 

This  plexus  commences  directly  above  the  bronchia  of  each  side. 
It  is  formed  principally  by  the  fasciculi  of  the  trunk  of  the  pneumo- 
gastric  nerve,  between  which  there  is  a very  vascular  mucous  tissue. 
It  extends  behind  the  bronchiæ  into  the  substance  of  the  lungs, 
surrounding  the  finest  ramifications  of  the  bronchial  tree,  to  the  mus- 
cular tunic,  and  even  to  the  mucous  membrane  to  which  it  sends  fila- 
ments. Beside  the  trunk  of  the  pneumo-gastric  nerve  which  develops 
itself  to  give  rise  to  it,  it  also  receives  some  filaments  which  are  less 
numerous,  from  the  superior  thoracic  and  from  the  inferior  cervical 
ganglion  of  the  great  sympathetic  nerve. 

Five  or  six  fasciculi  on  the  right  side  and  only  two  or  three  on  the 
left,  arise  from  the  lower  part  of  each  of  these  two  pulmonary  plexuses. 
These  fasciculi  are  first  situated  very  far  from  each  other,  but  fre- 
quently anastomose  by  intermediate  filaments.  After  passing  some 
lines  they  unite  on  each  side  in  a cord,  which  is  the  continuation  of 
the  trunk  of  the  pneumo-gastric  nerve,  and  the  right  of  which  is  larger 
than  the  left.  These  cords  descend,  that  of  the  left  before,  that  of  the 
right  behind,  and  at  the  side  of  the  esophagus. 

In  their  course  they  frequently  anastomose  principally  by  anterior 
filaments  which  descend  from  the  right  cord,  send  filaments  to  the 
esophagus,  and  others  which  are  smaller  to  the  aorta,  and  enter  the 
abdomen  with  the  esophagus,  passing  through  the  esopahgœan  fissure 
of  the  diaphragm. 

The  pneumo-gastric  nerve  terminates  in  the  stomach.  That  of  the 
right  side  which  is  the  largest,  goes  to  the  right  portion  and  the  pos- 
terior face  of  the  viscus  ; that  of  the  left  side  is  distributed  in  its  left 
part  and  on  its  anterior  face. 

The  right  forms  around  the  cardiac  orifice  a large  plexus,  from 
which  numerous  filaments  arise,  some  of  which  are  distributed  to  the 
posterior  face  of  the  stomach  ; others  situated  behind  the  coronary 


50 


DESCRIPTIVE  ANATOMY. 


artery  of  the  stomach,  proceed  along  its  small  curve  to  the  pylorus, 
and  there  anastomose  with  those  of  the  left  nerve  and  with  the  superior 
gastric  plexus  of  the  great  sympathetic  nerve  : finally,  some  which  do 
not  belong  to  the  stomach  pass  behind  it,  arrive  at  the  right  portion  of 
the  solar  plexus  and  also  the  plexuses  which  come  from  this  latter  on 
the  right  side,  and  are  distributed  to  the  hepatic  artery  and  its  branches, 
to  the  vena-portæ,  the  duodenum,  and  the  pancreas. 

The  left  divides  at  the  cardiac  orifice  into  several  branches  which 
separate  in  rays,  communicate  less  frequently,  follow  the  small  curve 
of  the  stomach  from  left  to  right,  send  ramifications  to  the  anterior  face 
of  this  viscus,  anastomose  near  the  pylorus  with  the  filaments  of  the 
right  pneumo-gastric  nerve,  and  leaving  the  stomach,  terminate  anteri- 
orly before  the  pylorus,  in  the  hepatic  plexus  formed  by  the  ganglion- 
nary  nerve. 


IV.  GLOSSO-PHARYNGŒAL  NERVE. 

§ 1858.  The  glosso-pharyngceal  nerve  (N.  glosso-pharyngœus,  Hal- 
ler; s.  lingtiulis  pnewnogastrici,  Vicq-d’Azyr;  s.  octavus,  Andersch), 
has  been  considered  until  lately  as  the  anterior  part  of  the  pneumo- 
gastric  nerve.  In  fact,  if  we  regard  its  origin,  the  communications 
between  it  and  this  nerve,  both,  within  the  skull  and  at  its  passage 
through  the  posterior  foramen  laeerum,  finally  the  manner  in  which  it 
is  distributed,  we  discover  that  it  really  forms  a part  of  the  pneumo- 
gastric  nerve,  but  it  is  so  largely  developed  that  it  may  be  considered  a 
proper  and  distinct  nerve.  It  arises  by  five  or  six  filaments,  which 
may  be  easily  separated  from  each  other,  and  the  anterior  of  which  are 
generally  smaller  than  the  posterior.  It  arises  between  the  pneumo- 
gastric  and  facial  nerves,  some  distance  behind  the  latter,  but  directly 
before  the  upper  filaments  of  the  first,  from  which  its  own  cannot  be 
separated.  It  comes  from  the  upper  part  of  the  lower  face  of  the 
inferior  prolongation  of  the  cerebellum,  from  the  depression  between 
this  cord,  the  olivary  bodies,  and  the  posterior  edge  of  the  annular  pro- 
tuberance, directly  behind  the  latter,  from  which  several  of  its  filaments 
sometimes  emanate.  It  goes  outward  and  at  first  a little  forward,  covered 
by  the  fourth  lobe  of  the  cerebellum,  usually  anastomoses  within  the 
skull  by  a large  branch  with  the  pneumo-gastric  nerve,(l)  and  after 
proceeding  five  or  six  lines,  passes  through  the  arachnoid  membrane. 
It  is  round  and  about  a half  or  three  quarters  of  a line  thick,  and 
emerges  from  the  skull  through  the  anterior  part  of  the  posterior  fora- 
men laeerum,  directly  before  the  pneumo-gastric  nerve,  but  inclosed  in 
a special  canal  of  the  dura-mater.  About  four  or  six  lines  from  its 
entrance  into  this  canal,  it  becomes  a small,  oblong,  rounded,  and  gene- 
rally very  distinct  ganglion  about  five  lines  long,  which  extends  into 
the  canal  of  the  dura-mater  and  the  anterior  part  of  the  foramen 
laeerum. 


(1)  Anderscli,  F'ragm.  descripl.  nerv.  cardiac.,  in  Ludwig,  loo.  cit.,  vol.  ii.  p.  115. 


OF  THE  NERVOUS  SYSTEM, 


51 


This  ganglion  gives  off,  above,  a filament,  which  enters  into  the 
cavity  of  the  tympanum,  and  then  divides  into  two  branches  ; one 
ascends  along  the  promontory,  gives  off  a small  filament  to  the  mem- 
brane of  the  foramen  rotundum,  and  passes  through  the  petrous  por- 
tion of  the  temporal  bone  to  the  superficial  temporal  nerve,  and  the 
other  passes  below  the  osseous  portion  of  the  Eustachian  tube,  and 
goes  to  the  carotid  canal,  where  it  anastomoses  with  the  great  sym- 
pathetic nerve.(l) 

The  ganglion  also  gives  off  other  filaments,  which  passthrough  the 
canal  of  the  dura-mater  to  go  to  the  trunk  of  the  pneumo-gastric,  to 
the  accessory,  and  the  great  sympathetic  nerves. 

After  emerging  from  the  posterior  foramen  lacerum,  'the  glosso- 
pharyngeal nerve  is  separated  from  the  pneumo-gastric  trunk  by  the 
internal  jugular  vein,  before  which  it  is  situated.  Thence  it  goes 
downward  and  forward,  passing  on  the  internal  carotid  artery,  descends 
situated  at  first  closely  on  the  outside,  then  on  the  anterior  part  of  this 
artery,  between  it,  the  external  carotid  artery,  and  the  stylo- pharyngceus 
muscle,  passes  between  this  muscle  and  the  glosso-pharyngceus  muscle, 
then  between  this  latter  and  the  hyoglossus,  and  thus  comes  to  the 
lower  and  posterior  part  of  the  tongue. 

On  leaving  the  skull  it  sends  a filament  of  anastomosis  to  the  stylo- 
hyoid branch  or  to  the  digastric  branch  of  the  facial  nerve  and  another 
to  the  trunk  of  the  pneumo-gastric  nerve.  It  then  gives  off  one  or  two 
which  descend  along  the  internal  and  the  primitive  carotid  arteries, 
anastomose  first  with  the  pharyngœal  branch  of  the  pneumo-gastric 
nerve,  and  then  going  to  the  lower  part  of  the  neck  communicate  with 
some  filaments  of  the  sympathetic  nerve  particularly  with  the  super- 
ficial or  even  the  middle  cardiac  nerves.  Still  farther  on,  it  sends  off 
three  or  four  filaments  to  the  stylo-pharyngeus  muscle,  and  also  to  the 
middle  and  superior  constrictors  of  the  pharynx  and  to  the  amygdalæ, 
and  some  which  enter  the  pharyngœal  plexus  of  the  pneumo-gastric 
and  the  ganglionnary  nerve. 

The  glosso-pharyngceal  nerve  then  passes  between  the  styloglossus 
and  hyoglossus  muscles  ; then  situated  in  the  tongue  below  the 
lingual  nerve  of  the  fifth  pair  and  above  the  hypoglossal  nerve,  both 
larger  than  it  and  with  which  it  does  not  communicate  at  least  by  very 
evident  filaments,  it  is  distributed  partly  in  the  muscles  of  the  tongue, 
the  membrane  of  the  soft  palate  and  the  amygdalæ  by  several  ramifi- 
cations which  interlace  like  a plexus  ; partly  in  the  integuments  of  the 
base  of  the  tongue,  its  large  papillæ,  and  the  mucous  membrane  of  the 
epiglottis  by  other  filaments  which  are  situated  lower  and  nearer  the 
median  line  than  the  preceding,  and  pass  from  below  upward  through 
the  substance  of  the  tongue. 


(1)  Rosenmuller,  Handbuch  der  Anatomic,  1816.  p.  407. — Jacobson,  in  the  Acta  reg. 
societ.  Hqfniensis  medicæ,  vol.  v.  Copenhagen,  1818.  p.  292.— This  anastomosis  has 
been  doubted  by  Kilian,  but  is  admitted  by  Lobstein. 


52 


DESCRIPTIVE  ANATOMY, 


V.  AUDITORY  NERVE. 

§ 1859.  The  auditory  or  acoustic  nerve,  labyrinthique , Ch.,  the  soft 
portion  of  the  seventh  pair  ( JY . auditorius , s.  acusticus , s.  portio  mollis 
nervi  acustici),(l ) is  very  soft,  but  harder  than  the  olfactory  and  the  por- 
tion of  the  optic  nerve  behind  the  decussation  ; it  generally  communicates 
so  evidently  with  all  the  white  striæ  of  the  floor  of  the  calamus  scrip - 
torms,  or  at  least  with  several  of  them,  that  it  may  be  said  to  arise 
partially  from  it. 

Its  upper  and  external  part  is  formed  by  these  striæ.  The  fibres 
connected  with  it  follow  one  another  from  before  backward  and  are 
separated  by  unequal  and  inconstant  spaces  ; they  turn  on  the  inferior 
prolongations  of  the  cerebellum,  on  the  surface  of  which  they  are  inti- 
mately connected.  Their  direction  is  forward  and  downward,  the 
anterior  proceeding  transversely,  the  posterior  obliquely  from  below 
upward. 

The  inner  part  of  the  nerve  is  larger  than  the  external  portion,  but 
they  are  not  separated  ; it  arises  below  and  farther  forward  than  it  from 
the  lateral  face  of  the  spinal  prolongation  of  the  cerebellum,  directly 
before  and  above  the  glosso-pliaryngœal  nerve  and  the  upper  part  of 
the  pneumo-gastric  nerve. 

The  trunk  of  the  nerve  then  goes  forward,  outward  and  downward 
on  the  posterior  edge  of  the  transverse  prolongation  of  the  cerebellum, 
and  is  united  to  its  upper  face  so  intimately  for  about  three  lines,  that  it 
may  properly  be  considered  as  arising  from  this  part  of  the  encephalon. 
It  is  slightly  covered  outward  by  the  fourth  lobe  of  the  cerebellum,  being 
often  attached  in  this  place  to  its  medullary  substance,  so  that  we  may 
admit  also  that  it  partially  arises  there,  which  is  worthy  of  note  but 
not  astonishing,  on  account  of  the  analogy  resulting  from  it  with  what 
is  seen  in  the  other  two  nerves,  the  optic  and  olfactory,  which  are  only 
nerves  of  sense. 

Its  internal  face  is  grooved  lengthwise,  and  receives  the  facial  nerve. 
It  is  soft  at  its  origin,  and  we  do  not  perceive  there  distinct  fibres,  but 
on  leaving  the  encephalon  it  evidently  becomes  fibrous  and  still  more 
solid. 

On  leaving  its  origin  the  auditory  nerve  goes  obliquely  forward, 
outward,  and  upward,  and  soon  penetrates  the  internal  auditory  fora- 
men, which  is  much  larger  than  it.  It  then  divides  into  two  branches, 
which  continue  united  externally  to  its  base  ; the  anterior  enters  the 
cochlea  and  the  posterior , the  vestibule  and  the  semicircular  canals. 
We  shall  describe  these  branches  when  speaking  of  the  ear. 

(1)  J.  F.  Meckel,  Obs.  anat.  sur  la  glande  pineale,  sur  la  cloison  transparente  et 
sur  Vorigine  de  la  septième  paire , in  the  Mêm.  de  Berlin , 1765.  p.  91—100.— A. 
Scarpa,  De  nervo  auditorio , in  his  Anat.  disquis.  de  auditu  et  otfadu,  Pavia,  1789, 
sect.  ii.  cap.  iii. 


OF  THE  NERVOUS  SYSTEM. 


53 


VI.  FACIAL  NERVE. 

§ I860.  The  facial  or  small  sympathetic  nerve,  the  hard  portion  of 
the  seventh  nerve,  the  seventh  pair,  th eseventh  cerebral  nerve  (JV.  facialis, 
s.  sympathicus  minor , s.  communis  facili,  s.  portio  dura  septimi,  s. 
nervus  primus  septimi  paris,  s.  par  septimum){  1)  is  much  smaller  than 
the  auditory  nerve  ; it  arises  by  two  roots  which  are  generally  distinct, 
although  placed  one  against  the  other.  One  is  external  and  posterior, 
the  other  much  larger  is  internal  and  anterior.  It  arises  within,  below, 
and  before  the  auditory  nerve,  which  receives  it  in  a groove  situated 
along  its  internal  face,  directly  at  the  side  of  this  nerve  and  before  the 
glosso-pharyngæal  nerve.  It  arises  from  the  posterior  edge  of  the 
annular  protuberance,  from  the  uppermost  part  of  the  lower  face  of  the 
rachidian  prolongation  of  the  cerebellum  ; sometimes,  also,  according 
to  Malacarne,  by  several  filaments  from  the  floor  of  the  fourth  Ven- 
tricle, that  is,  from  the  most  anterior  transverse  medullary  striae.  The 
filaments  from  the  annular  protuberance,  particularly  the  internal,  seem 
to  come  only  from  this  tubercle  ; but  examining  them  attentively,  we 
see  that  they  are  separated  from  the  principal  root  only  by  the  pos- 
terior fibres  of  the  protuberance  existing  between  this  latter  and 
them.(2)  Very  possibly,  however,  from  this  reason  they  are  in  fact 
separated  from  the  principal  root,  and  first  arise  from  the  pons  Varolii. 
The  external  root  of  the  nerve,  which  is  much  smaller  than  the  in- 
ternal, is  always  formed  of  three  or  four  filaments  which  unite  anteri- 
orly in  one  or  two  fasciculi.  It  is  situated  between  the  internal  root  and 
the  auditory  nerve,  and  some  of  its  filaments  frequently  seem,  at  least 
in  situation,  to  belong  to  the  auditory  nerve  rather  than  to  it. 

The  nerve  leaves  the  annular  protuberance  at  about  the  centre  of 
the  space  between  the  anterior  and  posterior  edges  of  this  latter,  goes 
forward  and  outward  to  arrive  at  the  internal  auditory  passage,  through 
which  it  proceeds  above  and  before  the  auditory  nerve  to  the  canal  of 
Fallopius,  which  it  exactly  fills,  and  passes  entirely  through  it.  Its 
direction  is  consequently  first  outward  and  backward,  then  downward 
behind  and  above  the  cavity  of  the  tympanum,  and  it  emerges  through 
the  stylo-mastoid  foramen,  to  be  distributed  in  a considerable  portion  of 
the  skin  and  of  the  muscles  of  the  head. 

In  its  course  along  the  canal  of  Fallopius,  it  gives  off  first  down- 
ward and  forward,  a filament  which  reunites  with  the  superior  branch 
of  the  recurrent  nerve  given  off  by  the  second  branch  of  the  fifth  pair, 
to  form  the  superficial  petrous  nerve  ( JV.  petrosus  superficialis). 

(1)  J.  H.  Meckel,  De  quinto  pare  nervorum  cerebri,  Gottingen,  1748,  for  the  por- 
tion of  the  facial  nerve  contained  in  the  Fallopian  canal. — J.  F.  Meckel,  Dissertation, 
anatomique  sur  les  nerfs  de  la  face,  in  the  Mém.  de  Berlin,  vol.  vii.  1752.— See  also 
Bock,  Beschreibung  des  fünf  ten  Nervenpaares,  Leipsic,  1817.  tab.  i.  ii. 

(2)  Gall,  loc.  cit. , p.  206.  r 

Yql.  III. 


8 


DESCRIPTIVE  ANATOMY. 


A4 

It  then  gives  off  a little  downward  and  outward,  behind  the  cavity 
of  the  tympanum,  one  or  several  filaments  for  the  muscles  of  the  little 
bones  of  the  ear. 

A little  lower,  some  distance  above  the  stylo-mastoid  foramen,  it 
sends  off  a considerable  branch,  the  cord  of  the  tympanum  ( chorda 
tympan; ),  which  descends  at  first  along  the  trunk,  then  goes  outward 
and  upward,  passes  through  the  posterior  wall  of  the  cavity  of  the 
tympanum,  enters  this  cavity  at  the  side  of  the  pyramid,  descends 
from  behind  forward  between  the  malleus  and  incus  situated  on  the 
former  bone  : it  anastomoses  by  one  or  more  filaments  with  the  tym- 
panitic nerves  of  the  fifth  pair,  but  gives  no  ramification  to  the  mem- 
brane of  the  tympanum,  leaves  the  tympanum  through  the  fissure  of 
Glaser,  descends  on  the  inside  of  the  ascending  branch  of  the  jaw,  and 
gradually  becoming  thicker,  anastomoses  at  an  acute  angle  with  a 
twig  of  the  lingual  branch  of  the  trifacial  nerve  which  meets  it. 

It  does  not  seem  to  us  probable,  from  our  dissections,  that  the 
superficial  petrous  nerve  and  the  cord  of  the  tympanum,  are  only 
a filament  of  the  fifth  pair,  which  is  fitted  to  the  facial  nerve,  and 
which  does  not  really  anastomose  with  it,(  1 ) although  we  consider 
the  lower  and  prominent  portion  of  the  cord  of  the  tympanum,  as  be- 
longing to  the  branch  of  the  trifacial  nerve. 

After  leaving  the  stylo-mastoid  foramen,  the  facial  nerve  gives  off 
the  following  branches: 

1st.  One  single  or  double  branch,  termed  the  posterior,  inferior , or 
deep  auricular  nerve  (JV.  auricularis  posterior , profundus  inferior) , 
which  sends  one  or  more  inconstant  filaments  into  the  mastoid  process, 
then  goes  upward  and  backward  and  divides  into  two  branches,  an 
anterior  and  a posterior,  the  former  of  which  is  the  larger. 

The  posterior,  which  sometimes  forms  the  first  branch  of  the  facial 
nerve,  ascends  on  the  mastoid  process,  is  distributed  in  the  skin  which 
covers  it,  extends  to  the  occipitalis  muscle,  to  which  it  distributes  fila- 
ments, and  anastomoses  with  the  ramifications  of  the  small  occipital 
nerve. 

The  anterior  arrives  at  the  lower  and  posterior  part  of  the  cartila- 
ginous portion  of  the  auditory  foramen,  and  of  the  external  ear,  sends 
some  filaments  to  the  skin  of  this  region,  and  also  to  the  posterior 
auricular  muscle,  and  passing  through  the  cartilage,  is  distributed  in 
the  integuments  of  the  auditory  passage. 

2d.  The  stylo-hyoid  nerve  (JY.  stylo- hyoidcus)  which  is  distributed 
partly  in  the  upper  portion  of  the  muscles  attached  to  the  styloid  pro- 
cess, and  the  posterior  part  of  the  digastricus  muscle  of  the  jaw,  and 
partly  sends  several  anastomosing  filaments  to  the  upper  part  of  the 
ganglionnary  nerve,  and  to  the  middle  cutaneous  nerve,  given  off  by 
the  third  cervical  nerve. 

3d.  A branch  termed  the  digastric  (R.  digastricus ),  which  passes 
through  the  posterior  belly  of  the  digastricus  muscle,  and  anastomoses 


(1)  Cloquet,  Tr.  d’anat.,  vol.  ii'-  p.  610. 


OF  THE  NERVOUS  SYSTEM, 


65 


with  the  ramifications  of  the  glosso-pharyngceal,  the  pneumo-gastric, 
and  the  accessory  nerves. 

4th,  Sometimes  a filament  which  anastomoses  with  the  posterior 
twig  of  the  inferior  auricular  nerve,  and  with  the  filaments  of  the 
anterior  branch  of  the  third  and  fourth  cervical  nerves.  This  filament 
exists  particularly  when  the  inferior  auricular  nerve  is  small. 

After  giving  off  these  ramifications,  the  trunk  of  the  facial  nerve, 
passing  under  the  ear,  enters  the  parotid  gland  from  above  downward 
and  from  behind  forward,  assumes  in  this  gland  a direction  which  is 
oblique  from  below  upward,  still  continuing  to  go  forward,  and  forms 
within  it  a considerable  plexus,  the  parotid  'plexus  (plexus  par otideus). 
This  plexus  i formed  by  the  nerve  dividing  at  the  posterior  edge  of  the 
ascending  branch  of  the  jaw,  into  from  two  to  five  branches,  which  may 
always  be  referred  to  two  which  vary  in  direction  and  distribution.  Of 
these  branches,  one  is  superior,  the  other  inferior,  and  smaller  than  the 
former.  They  anastomose  frequently  together,  and  thus  form  a 
polygon  convex  forward,  upward  and  downward,  whence  arise  the 
other  ramifications  of  the  nerve,  which  are  distributed  in  the 
6kin  of  the  upper,  middle,  and  lower  portions  of  the  face,  in  that  of  the 
upper  part  of  the  neck  and  in  most  of  the  muscles  of  the  face. 

Several  considerable  branches  constantly  unite  posteriorly  with  this 
plexus  ; they  come  from  the  superficial  temporal  nerves  which  arise 
from  the  third  branch  of  the  trifacial  nerve,  and  which  turn  from  be- 
hind forward  on  the  posterior  edge  of  the  ascending  branch  of  the 
jaw. 

By  examining  this  plexus  from  above  downward  and  from  behind 
forward,  we  observe  that  it  gives  off  some  ascending,  some  anterior, 
and  some  descending  branches,  which  frequently  anastomose  together 
by  intermediate  twigs,  equally  distant  from  the  edge  of  the  parotid 

gland. 

I.  ASCENDING  BRANCHES. 

§ 1861.  The  ascending  branches  are  the  temporal  and  the  malar 
nerves  (JV*.  temporales  et  malares).  Chaussier  terms  them  collectively 
the  temporo  facial  branch. 

a.  Temporal  nerves. 

§ 1862.  We  find, 

5th,  6th,  7th.  Two  or  three  temporal  nerves,  which  give  some  small 
filaments  to  the  parotid  gland,  ascend  on  the  malar  bone,  anastomose 
between  them  with  the  superficial  and  deep  temporal  branches  of  the 
submaxillary  nerve  posteriorly,  and  with  the  frontal  and  lacrymal  twigs 
of  the  first  branch  of  the  trifacial  nerve,  are  distributed  on  the  temporalis 
muscle,  and  send  ramifications  to  the  skin  of  the  temples,  to  that  of 
the  anterior  part  of  the  external  ear,  the  anterior  auricular  muscle, 


56 


DESCRIPTIVE  ANATOMY. 


and  the  external  and  upper  part  of  the  orbicularis  palpebrarum 
muscle. 

When  only  two  temporal  nerves  exist,  the  anterior  is  larger  than 
the  other. 


b.  Malar  nerves. 

§ 1863.  8th  and  9th.  These  are  usually  two  nerves  ; they  proceed 
more  forward  and  upward  than  the  preceding,  and  passing  on  the 
malar  bone,  they  are  distributed  in  the  skin  which  covers  this  bone  and 
the  external  edge  of  the  orbit,  in  the  outer  part  of  the  eyelids,  in  the 
external  and  lower  part  of  the  orbicularis  palpebrarum  muscle,  finally 
in  the  posterior  part  of  the  zygomatici  muscles. 


IL.  ANTERIOR  BRANCHES  OR  BUCCAL  NERVES. 

§ 1864.  There  are  usually  three,  more  rarely  two,  anterior  branches 
or  buccal  nerves  (JV.  buccales). 

The  central  one  is  the  largest. 

They  go  almost  directly  forward  on  the  upper  and  middle  portion  of 
the  masseter  muscle,  beyond  its  anterior  edge.  The  middle  is  situated 
directly  on  the  excretory  canal  of  the  parotid  gland. 

The  superior,  passing  under  the  zygomatici  muscles,  to  which  it 
gives  filaments,  ascends  towards  the  lower  eyelid,  and  goes  to  the 
inner  angle  of  the  eye,  where  it  often  anastomoses  with  the  infra- 
trochlear  nerve  given  off  by  the  fifth  pair. 

The  central  divides  into  ascending  and  anterior  twigs. 

The  ascending  twigs  arrive  at  the  lower  part  of  the  orbicularis 
palpebrarum  muscle,  the  muscles  of  the  sides  of  the  nose,  and  the  skin 
which  covers  them,  anastomose  with  some  filaments  of  the  infraorbitar 
nerve  which  come  from  the  fifth  pair,  particularly  with  the  external, 
and  terminate  in  the  levator  muscles  of  the  upper  lip,  the  orbicularis 
oris,  and  the  skin  of  the  upper  lip. 

The  inferior  go  directly  forward,  are  distributed  in  the  buccinator 
muscle,  the  skin  of  this  region  and  that  of  the  lower  lip.  They  anas- 
tomose wfith  the  buccal  nerve  which  comes  from  the  third  branch  of 
the  fifth  pair. 


III.  DESCENDING  BRANCHES. 

§ 1865.  The  descending  branches,  cervico-faciales,  Ch.,  arise  from 
the  lower  and  smaller  trunk,  which  commonly  anastomoses  at  its  origin 
by  some  filaments  with  the  superior. 

This  trunk  generally  divides  into  two  branches. 

The  superior  goes  forward  on  the  lower  part  of  the  masseter  muscle, 
anastomoses  with  the  inferior  buccal  nerve,  and  is  distributed  in  the 
skin  of  the  lower  bp,  the  depressor  labii  inferioris,  and  the  buccinator 
muscle. 


OF  THE  NERVOUS  SYSTEM, 


57 


The  inferior  descends  towards  the  lower  angle  of  the  jaw,  and 
divides  near  the  angle  of  this  bone,  into  a superior  and  an  inferior 
twig. 

The  superior  twig,  the  marginal  nerve  (N.  marginalia),  proceeds 
above  and  along  the  edge  of  the  lower  jaw,  goes  forward  and  upward, 
distributes  its  filaments  in  the  muscles  which  depress  the  lower  lip  and 
in  the  skin  of  the  chin,  and  anastomoses  with  the  inferior  labial  nerves 
of  the  third  branch  of  the  trifacial  nerve. 

The  inferior  divides  in  turn  into  two  or  three  ramuscules,  the  su- 
perior cutaneous  cervical  or  submaxillary  nerves  (JV.  subcutanei  colli  su- 
periores ),  which  descend  under  the  jaw,  are  distributed  in  the  upper 
part  of  the  skin  of  the  neck  and  in  the  platysma  myoides  muscle,  and 
anastomose  frequently  with  the  ascending  twigs  of  the  anterior  branch 
of  the  third  cervical  nerve. 

VII.  EXTERNAL  MOTOR  NERVE. 

§ 1866.  The  external  motor  nerve,  the  sixth  pair,  the  external  oculo- 
muscular  nerve  ( JY. '.  oculo-muscularis  externus,  s.  posterior,  s.  abducens, 
s.  par  sextum),{\)  is  flat,  and  arises  by  two  very  distinct  roots,  an 
internal  and  an  external  which  is  usually  four  times  the  size  of  the 
former,  from  the  upper  extremity  of  the  pyramid,  from  the  posterior 
edge  and  the  posterior  extremity  of  the  lower  face  of  the  annular  pro- 
tuberance, about  two  lines  from  the  median  line,  and  four  or  five  lines 
inside  of  the  facial  nerve.  From  the  inferior  face  of  the  annular  protu- 
berance only  the  inner  root  generally  arises,  which  sometimes  does  not 
extend  to  the  posterior  edge,  but  terminates  two  lines  from  this  edge 
and  arises  only  from  the  external  face  of  this  protuberance,  although 
we  cannot  follow  it  farther  either  backward  or  forward.  The  ex- 
ternal root  generally  arises  also  from  the  anterior  extremity  of  the  pyra- 
mid. These  two  roots,  particularly  the  internal,  are  formed  of  several 
fasciculi  which  are  easily  detached  from  each  other. 

It  is  very  rare  that  the  internal  root  is  the  larger, (2)  or  that  the 
filaments  by  which  the  nerve  arises  do  not  unite  in  two  distinct  roots. 

Sometimes  the  nerve  arises  only  from  the  pyramid.  Not  unfre- 
quently  it  comes  in  part  from  the  olivary  body  and  the  transverse  band 
which  is  often  found  between  the  summits  of  the  two  pyramids. (3) 

We  can,  however,  generally  demonstrate  particularly  by  compara- 
tive anatomy,  that  it  arises  from  the  medulla  oblongata  between  the 
olivary  bodies  and  the  pyramids,  much  lower  than  it  comes  from  them 
and  that  the  different  filaments  coming  from  the  olivary  bodies,  the 
small  transverse  striæ,  and  the  pons  Yarolii,  are  either  supplementary, 
or  as  is  true  particularly  of  those  from  the  annular  protuberance,  ap- 

(1)  Zinn,  Desc.  oculi  humani,  Gottingen,  1755,  tab.  vi. 

(2)  We  have  rarely  seen  this.  Vicq-d'Azyr  {Mém.  de  Paris,  1781,  p.  589)  observes 
also  that  this  arrangement  is  rare. 

(3)  Vicq-d’Azyr,  Toe.  tit.,  p.  689. 


68 


DESCRIPTIVE  ANATOMY. 


pear  to  be  distinct  roots  only  because  the  fibres  of  the  principal  root  of 
the  nerve  are  separated  from  each  other  at  their  upper  part  by  the  pos- 
terior fibres  of  the  pons  Varolii.(l) 

The  two  roots  generally  unite  before  passing  through  the  dura-ma- 
ter : sometimes,  however,  each  passes  through  a special  opening  in 
this  membrane  and  also  proceeds  three  or  four  lines  and  even  glides 
under  a special  fibrous  bridge  entirely  distinct  from  the  dura-rnater 
before  they  join.  In  the  cases  where  we  have  seen  this  arrangement 
it  has  ahuaijs  appeared  on  the  left  side  alone , and  the  external  fasci- 
culus was  the  smaller. 

These  facts,  compared  with  those  adduced  by  Sœmmerring,  seem 
much  in  favor  of  the  opinion  that  the  ganglionnary  nerve  comes  from 
the  centre  of  the  nervous  system,  and  that  the  cerebral  nerves  appear 
to  be  more  numerous  than  they  truly  are  by  the  enlargement  of  some 
branches.  If  proved  that  the  external  motor  nerve  always  divides  on 
the  left  side,  it  would  be  important  on  account  of  the  analogy  which  it 
establishes  with  the  vascular  system. 

On  leaving  the  encephalon  the  nerve  becomes  fibrous,  is  covered 
with  a neurilemma  and  goes  directly  forward  and  outward,  passes 
through  the  dura-mater  below  the  posterior  clinoid  process,  enters  the 
cavernous  sinus  within  which  it  is  attended  a short  distance  by  the 
arachnoid  membrane,  being  separated  from  the  blood  by  the  inner 
membrane  of  the  sinus,  and  is  situated  on  the  outside  of  the  internal 
carotid  artery  to  which  it  is  attached  by  compact  cellular  tissue.  In 
passing  above  the  anterior  orifice  of  the  carotid  canal  it  anastomoses 
with  the  ganglionnary  nerve  by  some  filaments  which  form  an  acute 
angle  with  its  trunk.  Farther  forward  it  communicates  also  by  a fila- 
ment with  the  spheno-palatine  ganglion,  or  the  recurrent  nerve  of  the 
second  branch  of  the  trifacial  nerve.  It  goes  to  the  orbit  through  the 
sphenoid  fissure  through  a special  opening  in  the  dura-mater,  enters 
this  cavity  between  the  fasciculi  of  the  rectus  oculi  externus  muscle, 
intimately  united  in  this  place  with  the  common  motor  nerve  and  the 
nasal  nerve  of  the  first  branch  of  the  tiifacial  nerve,  and  coming  on 
the  inside  of  the  rectus  externus  muscle  is  entirely  distributed  to  it. 

The  external  motor  nerve  goes  then  only  to  one  muscle.  It  very 
rarely  gives  off  the  nasal  branch  of  the  fifth  pair, (2)  but  more  fre- 
quently sends  a filament  to  the  opthalmic  ganglion. (3)  This  latter 
arrangement  makes  the  transition  from  that  commonly  found  to  the 
first.  This  anastomotic  filament,  however,  undoubtedly  belongs  at 
least  in  part  to  the  ganglionnary  system. 

t 

(1)  Gall,  loc.  cit.,  p.  204. 

(2)  Otto,  Seltne  Wahrnchmungén,  1816,  p.  103. 

(3)  Petit,  Mein,  de  Paris,  1727. 


OF  THE  NERVOUS  SYSTEM. 


59 


VIII.  TRIFACIAL  NERVE. 

§ 1867.  The  trifacial  nerve,  the  fifth  pair , (N.  trigeminus , s.  di- 
visas, s.  mixtus , Gj.11,  s.  pur  quintum  nervorum), ( 1)  is  very  large:  it 
appears  ab 3 at  six  lines  before  the  posterior  edge  of  the  inferior  prolon- 
gation of  the  cerebellum,  three  behind  the  anterior  edge  of  this  prolon- 
gation, and  nine  from  the  median  line  of  the  pons  Varolii.  There  it  is 
manifestly  composed  of  three  more  or  less  distinct  roots,  a posterior,  a 
central,  and  an  anterior.  The  posterior  is  situated  farther  backward 
and  higher  than  the  central,  and  the  anterior  below  and  on  the  inside 
of  it.  These  roots  were  first  correctly  described  by  Santorini, (2)  and 
after  him  by  Wrisbsrg,(3)  Palletta,(4)  and  Niemeyer.(5) 

§ 1833.  Tne  central  root  is  always  much  larger  than  the  other  two, 
for  it  is  more  than  a line  and  a half  in  diameter  after  it  emerges,  while 
each  of  the  others  is  only  about  half  a line.  Its  fasciculi  are  more 
numerous  : but  they  are  smaller  than  those  of  the  other  two  roots. 

At  the  place  where  it  emerges  it  is  a little  depressed  from  above 
downward,  but  soon  enlarges,  becomes  round,  and  again  contracts. 

The  fibres  of  the  annular  protuberance  evidently  separate  at  their 
base,  so  that  we  may  judge  from  a superficial  examination  that  the 
root  does  not  arise  in  this  place  but  from  a deeper  part. 

This  middle  root  is  composed  of  thirty  or  forty  fasciculi  of  various 
sizes.  The  number  of  filaments  which  form  these  fasciculi  is  about 
one  hundred  : some  authors  assert  less  ; but  they  probably  have  de- 
scribed the  fasciculi  simply  as  filaments,  or  have  neglected  to  decom- 
pose several  of  them. 

It  is  principally  by  following  the  central  root  that  we  can  demon- 
strate very  evidently  that  the  nerve  arises  from  a deeper  part  than 
where  it  leaves  the  annular  protuberance.  Santorini  has  stated  per- 
fectly its  true  origin  ;(6)  his  observations  have  been  confirmed  and 


(1)  J.  P.  Merkel,  De  quinto  pare  nervorum,  Gottingen,  1748. — A.  B.  R.  Hirsch, 
Paris  quinti  nervorum  encephali  disquisitio  anaiomica , Vienna,  1765. — H.  A.  W'ris- 
berg,  Observations  anatomicce  de  quinto  pare  nervorum  et  de  nervis , qui  ex  rodem 
duram  matremingredifalso  dicuntur,  Gottingen,  1777. — A.  C.  Rock,  Beischreibung 
der  fünften  Nervenpaares  und  seiner  Verbindung  mit  andern  Nerven,  vorzüglich 
dem  Gangliensystem,  Meissen,  1617. — G.  K.  Treviranus,  Sur  les  nerfs  de  la  cin- 
quième paire,  considérés  comme  organes  ou  conducteurs  de  sensations  ; in  the  Journ. 
compl.  du  diet,  des  sc.  méd.  vol.  xv.  p.  207. — Magendie,  Sur  les  fonctions  de  la 
cinquième  paire  de  nerfs  ; in  the  Journ.  de  phy.  exp.,  vol.  iv.  p.  176  and  302. 

(2)  Obs.  anal.,  Venice,  1724,  p.  65. 

(31  Loc.  cit. 

(4)  De  nervo  crotophilico  et  buccin a'orio,  Milan,  1784. 

(5)  De  origine  paris  quinti  nervorum  cerebri , Hales,  1812. 

(6)  Loc.  cit.,  p.  65.  T.  he  honor  of  this  discovery  then  belongs  to  Santorini. 
Niemeyer  seems  to  attribute  it  to  Winslow,  and  is  consequently  wrong,  for  the 
Anatomy  of  Winslow  appeared  first  in  1732,  while  Santorini’s  observations  were  pub- 
lished in  1724. 


60 


DESCRIPTIVE  ANATOMY. 


rendered  still  more  exact  by  the  labors  of  Winslow,(l)  Sœmmer- 
ring,(2)  Gall, (3)  and  Niemeyer.(4) 

Here  also  the  posterior  part  and  the  proper  origin  of  the  nerve  are 
covered  by  the  considerable  development  of  the  cerebral  parts.  On 
leaving  the  place  where  it  appears,  it  enters  from  without  inward,  from 
before  backward,  and  from  below  upward  in  the  fissure  of  the  central 
prolongation  of  the  cerebellum,  and  is  more  or  less  completely  divided 
into  several  cords  by  the  transverse  fibres  of  the  annular  protuberance, 
thus  comes  behind  the  union  of  the  three  peduncles  of  the  cerebellum 
directly  below  the  floor  of  the  fourth  ventricle,  passes  under  the  pos- 
terior prolongation  of  the  cerebellum,  almost  the  length  of  the  exteinal 
edge  of  the  annular  protuberance,  and  proceeds  towards  the  groove 
between  the  restiform  and  the  olivary  bodies  ; its  strongest  root  arises 
there  partly  from  the  groove  and  partly  from  the  olivary  eminences. 

From  this  point  to  where  it  passes  between  the  posterior  and  lateral 
prolongations  of  the  cerebellum  it  is  not  fibrous,  and  is  surrounded  by 
gray  substance  ; but  from  this  second  point  to  its  emerging  from  the 
annular  protuberance  it  is  formed  of  very  apparent  fibres,  and  is  sur- 
rounded by  a thin  membrane.  In  its  whole  extent  from  its  origin  to  a 
little  before  its  emerging  on  the  external  face  of  the  inferior  prolonga- 
tion of  the  cerebellum  it  gradually  becomes  thicker,  but  before  leaving 
the  pons  Yarolii  it  slightly  contracts  and  enlarges  considerably  after 
emerging. 

The  fasciculi  of  the  nerve  are  then  more  distinct  and  surrounded  with 
neurilemma,  and  occupy  the  w’hole  circumference  of  the  pons  Varolii. 
They  enlarge  partly  by  the  separation  and  partly  by  the  increase  of 
their  substance.  When  once  emerged,  the  nerve  is  at  first  round  but 
gradually  becoming  flatter,  goes  forward  towards  the  upper  end  of  the 
petrous  portion  of  the  temporal  bone.  At  first  it  is  loose  in  the  skull, 
being  loosely  surrounded  by  a broad  prolongation  of  the  arachnoid 
membrane,  but  at  the  upper  edge  of  the  petrous  portion  of  the  temporal 
bone  it  enters  a rounded  and  oblong  sheath  of  the  dura-mater  which 
generally  is  entirely  separated  from  the  cavernous  sinus.  This  sheath  is 
at  first  loose,  but  afterwards  is  placed  strongly  on  its  surface.  It  thus 
goes  from  before  downward  and  from  behind  forward  on  the  anterior 
face  of  the  petrous  portion  of  the  temporal  bone. 

In  this  course  the  trifacial  nerve  examined  externally  seems  formed 
only  by  fasciculi  placed  one  at  the  side  of  another.  These  fasciculi, 
however,  communicate  their  whole  extent,  by  small  intermediate  fila- 
ments. This  union  and  the  ramification  of  fasciculi  which  resultsfiom  it, 
become  more  and  more  marked  from  behind  forward,  and  for  about  a line 
and  a half  to  two  lines  the  breadth  of  the  fasciculi  divide  into  very  minute 

(1)  Exp.  anat.,  1732,  vol.  iv.  p.  182. 

(2)  Loc.  cit.,  p.  267. 

(3)  Lieber  das  Organ  des  Seele,  Koenigsberg,  1796,  p.  36. 

(4)  Loc.  cit.,  p.  211. 


OF.  THE  NERVOUS  SYSTEM. 


61 


filaments,  and  interlace  perpetually  with  each  other  near  its  anterior 
extremity.  The  trunk  of  the  nerve  which  here  touches  outward  the 
last  curve  of  the  internal  carotid  artery  anastomoses  with  some  fila- 
ments of  the  great  sympathetic  nerve. 

The  anterior  extremity  of  this  large  principal  root  suddenly  differs 
in  appearance  from  the  other  parts,  and  the  different  branches  of  the 
nerves. 

In  fact  at  the  anterior  extremity  of  the  upper  face  of  the  petrous 
portion  of  the  temporal  bone  it  forms  a semicircular  prominence,  the 
concave  edge  of  which  is  turned  upward  and  backward  and  the  convex 
edge  downward  and  forward.  This  prominence  which  reaches  be- 
yond the  trunk  of  the  nerve  in  every  direction  is  six  to  ten  lines  long 
from  before  backward,  one  broad  from  within  outward,  and  a line  and  a 
half  high.  It  is  termed  the  semilunar  ganglion  or  gangliform  plexus 
{ganglion  semilunare , plexus  ganglioformis , Vieussens  ; intumescentia 
ganglio  ajfinis,  Scarpa  ; plexus  retiformis,  Santorini  ; tarda  nervosa , 
Haller  ; intumescentia  semi-lunaris , Wrisberg  ; Jigger  lunatus,  Neu- 
bauer ; Armilla , Malacarne).  It  is  transparent  and  reddish,  and  for 
about  a quarter  to  half  a line  has  no  determinate  texture,  if  we  except 
some  filaments  which  pass  over  its  two  faces,  particularly  the  inner 
part  of  the  inferior  : but  it  then  reassumes  its  fibrous  appearance,  so 
that  in  the  mode  directly  the  opposite  of  that  over  the  plexus  the  fila- 
ments unite  from  above  downward  in  larger  threads,  and  thus  produce 
fasciculi,  still  forming  a trunk  from  one  and  a half  to  two  lines  broad, 
which  immediately  divides  into  three  principal  branches,  the  upper  of 
which  forms  with  the  crural  a very  acute  angle,  and  the  latter  a 
slightly  obtuse  angle  with  the  posterior.  The  branches,  the  fasciculi 
of  which  still  interlace  with  each  other,  are  at  first  broad,  but  they 
gradually  become  round  in  approaching  the  openings  through  which 
they  pass. 

The  plexiform  filaments  of  the  nerve  are  not  generally  continuous 
with  the  inferior,  but  terminate  in  a channel  grooved  on  the  upper  and 
concave  edge  of  the  ganglion.  The  inferior  arise  from  all  the  circum- 
ference of  the  ganglion,  and  most  generally  extend  to  the  upper  and 
concave  edge  externally.  The  substance  of  the  ganglion  is  homo- 
geneous internally,  and  precisely  similar  to  that  of  the  proper  nervous 
ganglions. 

§ 1869.  The  small  roots  of  the  trifacial  nerve  do  not  contribute  to 
form  the  prominence  of  the  ganglion,  although  there  is  on  the  lower 
face  of  this  latter,  and  of  the  large  root,  a groove  formed  by  their  pas- 
sage. 

The  superior  penetrates  through  a special  fissure  into  the  inferior  pro- 
longation of  the  cerebellum  from  one  fourth  of  a line  to  two  lines  dis- 
tant from  the  great  middle  root.  When  the  two  roots  are  very  near  each 
other  they  seem  to  enter  through  the  same  fissure  : but  in  attentively 
examining  we  perceive  this  is  rarely  the  case,  even  if  it  ever  happens. 
The  direction  of  the  superior  root  in  the  inferior  prolongations  of  the 
cerebellum  is  the  same  as  that  of  the  preceding,  which  proceeds  below 

Vol.  Ill  9 


62 


DESCRIPTIVE  ANATOMY. 


it;  we  however  cannot  trace  the  former  as  far.  Soon  after  emerging', 
it  turns  on  the  upper  face  and  the  inner  edge  of  the  large  root,  arrives 
at  its  lower  face,  and  continuing  to  pass  on,  it  goes  gradually  outward 
where  it  reunites,  after  passing  about  half  an  inch,  with  the  small  in- 
ferior roots.  It  is  formed  of  from  three  to  six  fasciculi  of  different  sizes. 

The  small  inferior  root  is  generally  nearer  the  central  than  the  su- 
perior, being  often  only  a fourth  of  a line  and  seldom  more  than  one 
line  distant  from  it,  and  the  rule  mentioned  by  Palletta  that  they  are 
always  several  lines  distant  cannot  be  admitted.  They  often  evidently 
arise  from  the  same  groove.  The  part  of  the  small  inferior  root  which 
is  contained  in  the  cerebral  substance  always  proceeds  below  the  large 
in  the  same  direction  with  it,  and  less  distant  from  it  than  is  the  upper 
root.  It  is  generally  formed  of  a greater  number  of  fasciculi  than  the 
upper,  as  there  are  about  from  six  to  eight.  It  leaves  the  annular 
protuberance  on  the  lower  face  of  the  large  root,  and  reunites  with  the 
small  superior  root  in  the  manner  stated,  most  generally,  three  or  four 
lines  behind  the  ganglionnary  prominence  of  the  large  root.  The  trunk 
of  the  temporo-buccal  nerve  (N.  crotciphito-buccinalorius),  formed  by  this 
union,  passes  first  under  the  large  root,  then  under  the  ganglionnary 
prominence  and  the  third  branch  of  the  fifth  pair,  thus  goes  outward 
and  forward,  and  anastomosing  in  this  course  only  by  some  inconstant 
filaments,  first  with  this  trunk,  then  with  the  third  branch  of  the  fifth 
pair,  often  but  not  always  enlarges  longitudinally  under  the  plexiform 
ganglion,  and  after  passing  through  the  foramen  rotundum  of  the  ba- 
silar bone  proceeds  to  form  the  temporal  and  buccal  nerves. 

These  two  small  roots  form  the  small  portion  of  the  fifth  pair,  which 
is  whiter  and  harder  than  the  large. 

Their  separation  with  the  ganglion  formed  by  the  large  portion  is 
extremely  curious,  as  it  presents  a repetition  of  the  formation  peculiar 
to  the  nerves  of  the  spinal  marrow. 

A.  FIRST  PRINCIPAL  BRANCH. 

§ 1870.  The  first  branch , the  superior  or  ophthalmic  branch  of  the 
fif III  pair  (R.  primus , s.  superior , s.  ophthalmicus), (1)  is  much  smaller 
than  the  other  two,  and  arises  from  the  upper  part  of  the  ganglion. 
Its  direction  is  from  below  upward  and  from  behind  forward  on  the 
outer  side  of  the  cavernous  sinus  towards  the  orbit,  into  which  it  pene- 
trates from  within  outward,  on  the  outside  of  the  common  motor  and 
below  the  superior  motor  nerve. 

In  this  course  it  gives  off  no  branches,  except  nearer  or  farther  from 
its  origin  a tolerably  constant  twig  which  unites  to  the  superior  motor 
nerve,  and  another  less  constant  which  goes  to  the  ganglionnary  nerve. 

(1)  Rinn,  DcscripLlo  oculi  humani,  tab.  vi.— Soœnnnening,  in  Demeura,  Traite 
des  maladies  des  yeux,  vol.  i v.,  p.  32,  pl.  vi.,  fi  g.  I. 


OF  THE  NERVOUS  SYSTEM. 


63 


But  it  is  united  in  all  its  extent  by  very  compact  cellular  tissue  with 
the  superior  motor  nerve. 

Just  before  entering  the  orbit  it  generally  divides  into  two  and  more 
rarely  into  three  twigs,  which  aie  the  nasal , the  lachrymal,  and  the 
frontal  nerves.  In  the  first  case,  the  second  blanch,  which  is  larger 
than  the  other,  is  the  common  trunk  of  the  lachrymal  and  frontal 
nerves. 

1st.  The  nasal  or  nnso-ciliary  nerve  (N.  naso-ocularis , s.  naso- 
ciliaris),  which  in  respect  to  size  is  between  the  other  two,  anasto- 
moses posteriorly  with  some  filaments  of  the  great  sympathetic  nerve, 
and  divides  into  two  branches  generally  before  entering  the  orbit. 

The  external  branch  (R.  ciliaris,  s.  ad  ganglion ) is  the  smaller,  and 
goes  to  the  lenticular  or  ciliary  ganglion  ( ganglion  lenticulare,  s. 
ciliare ),  which  is  situated  on  the  outside  of  the  optic  nerve  and  forms 
its  long  root.  Sometimes  it  anastomoses  previously  by  one  or  two  fila- 
ments with  the  common  motor  nerve.(l)  It  rarely  gives  off  a ciliary 
nerve. 

The  internal  branch  is  larger  and  proceeds  forward  and  inward  on 
the  optic  nerve,  with  which  it  is  connected.  It  not  unfrequently  gives 
off  some  ciliary  nerves  which  proceed  along  the  optic  nerve  to  the  eye 
and  enter  its  capsule  at  its  posterior  part,  proceed  between  the  fibrous 
envelop  and  the  choroid  membrane  to  the  iris,  in  which  they  are  distri- 
buted with  analogous  but  more  numerous  filaments  which  come  from 
the  lenticular  ganglion,  forming  with  them  from  five  to  ten  nerves  which 
generally  divide  again  into  two,  more  rarely  into  three  fasciculi,  which 
we  shall  describe  when  speaking  of  the  eye.  Several  filaments  from 
the  ganglionnary  nerve  enter  the  ganglion. (2) 

The  nerve  then  passes  below  the  rectus  oculi  superior  and  obliquus 
major  muscles,  continues  Bto  proceed  inward  and  forward,  situated 
against  the  internal  wall  of  the  orbit,  and  soon  divides  into  two 
branchés,  the  ethmoidal  and  the  infra-trochlear  nerves. 

The  ethmoidal  or  internal  nasal  nerve  (N.  cthmoidalis,  s.  nasalis, 
Winslow,  s.  ophthalmicus,  Willis,  s.  nasalis  internus ),  re-enters  the 
skull  through  the  internal  and  anterior  orbitar  foramen,  afterwards 
emerges  from  this  cavity  through  one  of  the  anterior  foramina  of  the 
cribriform  plate  of  the  ethmoid  bone,  proceeds  to  the  nasal  fossa,  sends 
filaments  to  the  mucous  membrane  of  the  superior  turbinated  bone  and 
of  the  septum,  sends  others  to  that  of  the  frontal  sinus,  then  glides  in  a 
groove  of  the  nasal  spine  of  the  frontal  and  of  the  proper  nasal  bones, 
descends  along  the  anterior  edge  of  the  cartilaginous  septum  of  the 
nose  to  the  nasal  fossee,  emerges,  and  terminates  at  the  tip  of  the  nose 
sending  filaments  to  its  alæ,  at  the  end  of  which  it  anastomoses 


(1)  Bock,  loc.  cit.,  p.  11. 

(2)  Kibes,  Sur  quelques  parties  de  l’œil  ; in  the  Mêm.  de  la  soc.  méd.  d’êm.,  vol. 
vii.,  p.  86. — Bock,  loc.  cit.,  p.  12. 


64 


DESCRITTIVE  ANATOMY. 


with  some  twigs  of  the  second  branch  of  the  fifth  and  the  seventh 
pairs.(l) 

The  ethmoidal  nerve  sometimes  divides  into  an  anterior  and  a pos- 
terior trunk,  the  latter  of  which  passes  through  the  internal  and  pos- 
terior orbitar  foramen,  and  remains  in  the  nasal  fossa. (2) 

The  infra-trochlear  or  external  nasal  nerve  ( N . infra-irochlearis), 
advances  below  the  rectus  and  obliquas  superior  oculi  muscles,  along 
the  inner  wall  of  the  orbit,  passes  directly  below  the  pully,  and  gives  off 
a small  filament  to  the  mucous  bursa  in  this  place,  leaves  the  orbit,  and 
divides  in  the  internal  angle  of  the  eye  into  two  principal  branches,  a 
superior  and  an  inferior.  These  branches  soon  subdivide  into  twigs  by 
which  the  nerve  is  distributed  in  the  tunica  conjunctiva,  the  caruncula 
lachrymalis,  the  lachrymal  sac,  the  orbicularis  palpebrarum  and  the 
frontalis  muscles,  and  the  skin  of  the  back  of  the  nose.  It  anastomoses 
above  with  the  supra-trochlear  nerve,  then  with  some  filaments  of  the 
facial  nerve,  and  farther  forward  with  the  second  branch  of  the  fifth  pair. 

Sometimes  the  long  root  of  the  lenticular  ganglion  does  not  come 
from  the  nasal  nerve,  but  from  the  third  pair.  Analogous  to  this  ar- 
rangement but  much  more  rare  is  the  case  where  the  nasal  nerve 
comes  from  the  sixth(3)  and  not  from  the  fifth  pair. 

2d.  The  frontal  branch  or  nerve  (N.  frontalis ),  the  largest  of  the 
three  branches  of  the  ophthalmic  nerve,  proceeds  between  the  other 
two  from  behind  forward  and  from  without  inward  on  the  levator  pal- 
pebræ  superioris  muscle  directly  below  the  arch  of  the  orbit.  It  is  at 
first  intimately  united  with  the  superior  motor  nerve. 

At  about  its  centre  it  sends  off  inward  and  forward  a small  branch 
which  anastomoses  with  the  infra-trochlear  nerve,  and  which  sends 
filaments  into  the  frontal  sinus,  either  directly,  or  indirectly  by  a small 
ganglion. 

It  then  sends  off  a larger  filament,  the  supra-trochlear  nerve  (N. 
supratrochlearis ),  which  proceeds  along  the  internal  wall  of  the  orbit, 
passes  above  the  pully  of  the  obliquus  major  muscle,  and  emerges  from 
the  cavity  of  the  orbit.  This  nerve,  called  also  the  internal  frontal 
nerve,  is  reflected  from  below  upward,  distributes  its  twigs  in  the 
corrugator  supercilii  muscle,  the  internal  and  upper  part  of  the  orbicu- 
aris  palpebrarum,  the  frontalis  muscle  and  the  skin  which  covers  it,  and 
anastomoses  with  some  filaments  of  the  infra-trochlear  and  the  proper 
frontal  nerve. 

The  continuation  of  the  trunk,  the  proper  frontal  nerve,  gives  off  no 
branch  within  the  orbit,  leaves  this  cavity  sometimes  in  one  root  but 
sometimes  divided  into  several,  through  one  or  more  supra-orbitar  fora- 
mina, is  soon  reflected  from  below  upward  on  the  upper  edge  of  the 
orbit,  and  is  distributed  in  the  skin  of  the  forehead  and  the  vertex. 

(3)  Hunter,  Observations  on  different  parts  of  animal  economy , London,  1792 .—A 
description  of  some  branches  of  the  fifth  pair  of  nerves , p.  265. 

(2)  Bock,  loc.  cit.,  p.  18. 

(3)  Otto,  Seltne  Beobachtungen , Breslau,  1816,  p.  108. 


OF  THE  NERVOUS  SYSTEM. 


65 


3d.  The  lachrymal  nerve,  (N.  lachrymalis)  which  is  between  the 
other  two  in  size,  and  is  the  most  external  of  the  three  twigs  of  the 
first  branch  of  the  fifth  pair,  goes  forward  and  outward,  being  also 
situated  against  the  orbitar  plate,  and  soon  divides  into  an  external 
and  an  internal  branch. 

The  external  reunites  with  a twig  of  the  subcutaneous  malar  nerve, 
which  comes  from  the  second  principal  branch  of  the  fifth  pair.  From 
this  trunk  we  generally  see  a filament  depart  which  is  sometimes 
double,  and  which  passing  directly  to  the  anterior  extremity  of  the 
inferior  orbitar  fissure,  between  the  malar  and  sphenoid  bones,  goes 
outward  in  the  temporal  fossa,  where  it  anastomoses  with  a malar 
branch  of  the  facial  nerve,  more  rarely  with  the  superficial  temporal 
nerve  which  comes  from  the  second  principal  branch  of  the  fifth 
pair.(l) 

This  external  branch  sometimes  sends  a filament  to  the  ciliary 
nerves,  which  come  directly  from  the  nasal  nerve. (2) 

The  internal  branch  divides  into  several  twigs,  which  anastomose 
with  each  other  like  a plexus,  and  enter  the  lachrymal  gland. 

These  twigs  are  not  distributed  entirely  in  the  gland.  Some,  after 
passing  through  it,  come  outwardly,  where  they  are  distributed,  partly 
in  the  external  part  of  the  orbicularis  palpebrarum  muscle,  partly  in 
the  integuments  of  the  malar  region,  and  anastomose  with  some  fila- 
ments from  the  posterior  branches  of  the  facial,  the  frontal,  and  the 
subcutaneous  malar  nerves. 


B.  SECOND  PRINCIPAL  BRANCH. 

§ 1871.  The  second  principal  branch  of  the  fifth  pair,  the  middle 
branch,  the  superior  maxillary  nerve  (R.  quinti  paris  secundus,  s. 
médius , s.  JV*.  maxillaris  superior), (3)  is  between  the  other  two  in 
its  situation  and  volume.  It  arises  from  the  anterior  part  of  the  gan- 
gfionnary  plexus  ; it  goes  almost  directly  forward,  or  at  least  a little 
oblique  from  below  upward,  gives  off  no  branch  within  the  skull, 
although  it  sometimes  anastomoses  there  with  a filament  of  the  gan- 
glionnary  nerve, (4)  and  emerges  from  this  cavity  outward  and  for- 
ward through  the  great  foramen  rotundum  of  the  sphenoid  bone.  It 
is  flat,  but  after  emerging  it  becomes  round. 

Some  distance  from  the  place  where  it  leaves  the  skull,  the  superior 
maxillary  nerve  gives  off  a small  branch,  the  subcutaneous  malar 
nerve  (JV*.  subcutaneus  males),  which  reascends  in  the  spheno-maxil- 
lary  fissure.  This  branch  enters  into  the  orbit  below  the  rectus  ex- 
ternus  oculi  muscle,  and  anastomoses  by  one  or  more  filaments  with 

(1)  Bock,  loe.  cit.,  p.  19. 

(2)  Bock,  loc.  cit.,  p.  20. 

(3)  J.  F.  Meckel,  De  quinto  pare  nervorum;  in  Ludwig',  Opp.  min.,  Gottingen, 
1817. — A.  Scarpa,  Annot.  acad.,  1.  ii.,  Modene,  1779.  cap.  iv.  v.  vi.  tab.  i.  ii. 

(4)  Laumonier,  in  Roux,  Journ.  de  méd.,  vol.  xciii.  p.  259. 


66 


DESCRIPTIVE  ANATOMY. 


the  external  twig  of  the  lachrymal  nerve.  It  sends  off,  farther  for- 
ward, one  or  more  ramifications,  which  enter  into  the  lachrymal  gland  ; 
some  of  them  remain  in  its  tissue,  while  others,  after  passing  through 
it,  emerge  from  the  orbit  and  are  distributed  in  the  orbicularis  palpe- 
brarum muscle  and  the  skin  of  the  cheek,  where  they  communicate 
with  some  filaments  of  the  facial  nerve  and  of  the  third  principal 
branch  of  the  fifth  pair.  Finally,  the  subcutaneous  malar  nerve 
emerges  from  the  orbit  through  the  malar  foramen,  sometimes  in  one 
trunk,  and  sometimes  divided  into  several  filaments.  It  is  distributed  on 
the  face  to  the  lower  part  of  the  orbicularis  palpebrarum  muscle,  and 
also  to  the  skin  of  the  malar  region,  and  communicates  with  the  twigs 
of  the  facial  and  infraorbitar  nerves. 

The  superior  maxillary  nerve  then  divides  into  two  much  larger 
and  nearly  equal  branches,  which  proceed  almost  directly  from  above 
downward.  They  are  the  pterygo-palatine  and  the  infraorbitar 
nerves. 

The  jjter'ygo-joalatine  nerve  ( JV.  pterygo-palatinus ) sometimes  forms 
a single  trunk,  sometimes  arises  by  two  or  three  distinct  filaments, 
winch  become  the  roots  of  a small  rounded  triangular  or  cordiform 
ganglion,  situated  on  the  outside  of  the  spheno-palatine  foramen,  and 
termed  from  its  discoverer,  the  ganglion  of  Meckel  (G.  .Meckelii),(l) 
and  also  the  spheno-palatine  ganglion  (G.  spheno-palalinum).  The 
recurrent  and  palatine  nerves  come  from  this  ganglion. 

The  branches  coming  from  the  pterygo-palatine  ganglion,  vary  ac- 
cording as  the  spheno-palatine  ganglion  does  or  does  not  exist. 

If  it  exists,  the  upper  anterior  nasal  nerves  partially  arise  from  the 
trunk  of  the  pterygo-palatine  nerve,  partly  from  the  palatine  nerve, 
and  the  naso-palatine  nerve  comes  from  the  pterygo-palatine. 

Several  small  branches  come  from  the  trunk  of  the  pterygo-palatine 
nerve,  and  from  the  spheno-palatine  ganglion  when  they  exist. 

First  arises  a filament  which  enters  the  sphenoidal  sinus,  or  which, 
when  it  is  very  much  developed,  passes  through  this  cavity  and  goes 
to  the  external  motor  nerve,  with  which  it  anastomoses  ;(2)  sometimes 
it  sends  ramifications  to  the  sphenoidal  sinus,  and  also  to  the  posterior 
and  most  superior  part  of  the  septum  of  the  nasal  fossæ. 

Next  come  four  or  five  filaments  which  are  a little  larger;  they  pass 
through  the  dura-mater,  which  is  extended  on  the  pterygo-palatine 
foramen,  are  distributed  in  the  mucous  membrane  which  lines  the  pos- 
terior part  of  the  upper  and  middle  turbinated  bones  of  the  nose,  and 
anastomose  with  the  ramifications  of  the  olfactory  nerve.  They  are 
the  upper  anterior  nasal  or  the  spheno-palatine  nerves  (N.  nasales 
superiores  et  anteriores).  Farther  on  are  the  nerve  of  the  septum , which 
will  be  described  more  properly  after  the  naso-palatine  nerve,  and  the 


(1)  J.  F.  Meckel,  Observation  anatomique  sur  un  nœud  ou  ganglion  du  second 
rameau  de  la  cinquième  paire  des  nerfs  du  cerveau  nouvellement  découvert  avec 
l’examen  physiologique  du  veritable  usage  des  nœuds  ou  ganglions  des  nerfs  ; in 
Mém.  de  Berlin , 1749.  p.  84,  103.  tab.  iii. 

(2)  Bock,  toc.  cit.,  p.  26. 


OF  THE  NERVOUS  SYSTEM. 


67 


upper  posterior  nasal  nerves,  which,  however,  are  more  frequently 
branches  of  the  recurrent  nerve. 

The  pterygo-palatine  nerve  then  divides  in  the  summit  of  the  pterygo- 
palatine fossa,  into  a recurrent  and  a descending  branch. 

The  recurrent  branch,  the  pterygoid  or  vidian  nerve  (JV.  quinti  re- 
current;,  s.  anastomoticus,  s.  pterygoideus , s.  vidianus ),  is  so  termed 
from  its  direction  ; for  it  goes  backward,  enters  into  the  pterygoid  fora- 
men, and  anastomoses  by  several  filaments  with  the  facial  and  great 
sympathetic  nerves. 

This  nerve  gives  off  first  inward  and  downward,  two  or  three  fila- 
ments termed  the  posterior  and  superior  nasal  nerves  (JV.  nasales  pos- 
teriores superiores ),  which  sometimes  unite  in  a small  trunk,  termed 
by  Bock,  the  pharyngœal  nerve  (R.  pharyngœus).  These  nervesemerge 
sometimes  through  the  lower  part  of  the  spheno-palatine  foramen, 
sometimes  pass  through  the  inner  wall  of  the  pterygoid  canal,  penetrate 
inward  through  the  pterygoid  process,  and  are  distributed  in  the  pos- 
terior part  of  the  mucous  membrane  of  the  nose,  where  they  anas- 
tomose with  the  ramifications  of  the  olfactory  nerves  in  the  muscles  of 
the  velum  palati,  the  skin  of  the  soft  palate,  and  around  the  anterior 
orifice  of  the  Fallopean  tube.  * 

The  external  part  of  the  nerve  which  is  remarkable  for  its  softness 
and  reddish  color,  then  divides,  before  leaving  the  pterygoid  canal  into 
two  branches,  which  sometimes  remain  distinct  to  the  ganglion,  and 
by  which  it  terminates. 

These  two  branches  are  the  anastomotic  nerves.  The  smaller 
superior  or  superficial  nerve  is  the  superficial  petrous  nerve  (JV. 
petrosus  superficialis) . It  proceeds  generally  single,  seldom  divided,, 
through  the  fibro-cartilage,  situated  between  the  sphenoid  bone  and 
the  petrous  process,  goes  backward,  upward,  and  outward,  under  the 
third  principal  branch  of  the  fifth  pair,  in  a groove  on  the  upper  face  of 
the  petrous  process,  leaves  this  groove  and  enters  the  Fallopian  canal, 
anastomoses  here  with  the  facial  nerve  which  passes  through  it,  and 
sometimes  sends  filaments  to  the  branches  of  the  ganglionnary  nerve 
which  surround  the  upper  part  of  the  carotid  artery  like  a plexus.(l) 

The  inferior  or  deep,  the  larger,  proceeds  in  the  same  direction  as 
the  recurrent  nerve,  emerges  from  the  posterior  extremity  of  the  ptery- 
goid canal  through  the  fibro-cartilage,  between  the  sphenoid  bone  and 
the  petrous  process,  goes  outward  and  backward,  passes  through  the 
dura-mater,  and  goes  into  the  carotid  canal,  where  ii  anastomoses  with 
the  upper  extremity  of  the  ganglionnary  nerve,  conjointly  with  a fila- 
ment of  the  sixth  pair,  thus  forming  a very  constant  and  very  evident 
anastomosis  between  the  fifth  pair  and  the  great  sympathetic  nerve. 

The  differences  sometimes  observed  in  this  respect  will  be  more  in 
place  in  the  description  of  the  great  sympathetic  nerve.  In  fact,  it  is 
probably  more  correct  to  consider  the  deep  branch  of  the  recurrent 
nerve  as  a ramification  of  this  latter. 


(1)  Bock,  loc.  cit.,  p.  28, 


68 


DESCRIPTIVE  ANATOMY. 


The  descending  branch  or  the  palatine  nerve  ( N . palatinus ) is  much 
larger  than  the  recurrent,  and  is  distributed  to  the  middle  and  lower 
part  of  the  mucous  membrane  of  the  nose,  and  also  to  the  membrane 
of  the  palate.  It  is  then  more  properly  termed  the  naso-palatine  nerve 
( N . naso  palatinus.) 

From  this,  or  from  the  spheno-palatine  ganglion,  or  finally  from  the 
trunk  of  the  pterygo-palatine  nerve,  arises  first  the  nerve  of  the  septum 
of  the  nose  (iV.  septi  narium ),  which  Scarpa(l)  less  properly  terms 
the  naso-palatine  nerve  (N.naso-palatinus).( 2) 

This  nerve  enters  the  nose  with  the  anterior  and  superior  nasal 
nerves,  through  the  spheno-palatine  foramen,  proceeds  from  without 
inward,  passing  before  the  sphenoidal  sinus  towards  the  septum  on 
which  it  descends  from  behind  forward,  between  the  periosteum  and 
the  mucous  membrane,  to  the  anterior  palatine  foramina,  farther  for- 
ward on  the  left  than  on  the  right  side,  and  thus  arrives  at  the  mem- 
brane of  the  palate.  In  passing  through  the  palatine  canal  the  nerves 
of  the  two  sides  unite,  sometimes  form  a small  prominence  termed  the 
naso-palatine  ganglion  ( G.  naso-palatinum ),  and  expand  on  a promi- 
nence situated  below  the  anterior  palatine  foramen. 

The  palatine  nerve  then  divides  into  a large  anterior  branch,  the 
continuation  of  the  trunk,  and  two  or  three  smaller  and  posterior,  all  of 
which  descend  into  the  pterygo-palatine  fossa.  These  branches  are 
the  great  and  small  palatine  nerves  ( N . palatini  major  et  minores). 
They  sometimes  arise  directly  from  the  ganglion,  or  even,  as  is  true 
particularly  of  the  smallest,  from  the  second  principal  branch. 

From  the  anterior  part  of  the  great  palatine  nerve  arise  first  the 
middle  and  inferior  posterior  nasal  nerves  ( N . nasales  posteriores  medii 
et  inferiores). (3) 

The  posterior  middle  nasal  nerve  soon  divides  into  two  branches, 
which  are  sometimes  separate  at  their  origins.  The  superior  goes 
directly  forward  in  the  mucous  membrane  of  the  middle  turbinated 
bone.  The  second  goes  to  the  upper  part  of  that  of  the  inferior  turbi- 
nated bone. 

The  posterior  inferior  nasal  nerve  arises  much  lower,  opposite  the 
posterior  extremity  of  the  lower  turbinated  bone,  towards  which  it  pro- 
ceeds directly,  and  sends  its  filaments  into  the  mucous  membrane  which 
lines  the  inner  face  of  this  bone  anteriorly. 

These  two  nerves  anastomose  with  the  ramifications  of  the  olfactory 
nerve. 

The  anterior  branch  of  the  great  nasal  nerve  sends  directly  back, 
ward  a small  twig,  which  passes  through  the  pterygoid  process  in  a 
special  canal,  and  is  distributed  to  the  glandular  substance  of  the  soft 
palate. 

(1)  Loc.  cit.,  cap.  v.  De  nervo  palatino. 

(2)  Scarpa,  loc.  cit.,  tab.  i.— Hunter,  Observations  on  different  parts  of  the  animal 
economy,  tab.  xvii. 

(3)  Cloquet,  loc.  cit.,  vol.  ii.  p.  687. 


OF  THE  NERVOUS  SYSTEM. 


69 


The  branch,  the  fasciculi  of  which  separate  from  each  other,  goes 
forward  and  downward  in  the  pterygo-palatine  canal,  and  comes 
through  the  posterior  palatine  foramen  to  the  lower  face  of  the  bony 
palate,  where  it  immedia.tely  divides  into  three  or  four  considerable 
branches  which  proceed  between  the  mucous  membrane  and  the 
periosteum,  along  the  inner  face  of  the  alveolar  processes  opposite  the 
teeth,  and  are  distributed  in  the  gum. 

The  two  or  three  small  palatine  nerves  descend  behind  the  great 
palatine  nerve,  first  in  the  pterygo-palatine  fossa,  then  lower  in  small 
special  canals  of  the  petrous  portion  of  the  temporal  bone,  on 
emerging  from  which,  they  enter  into  the  amygdalæ,  the  palato- 
staphylinus  muscle,  the  muscular  and  glandular  substance  of  the 
soft  parts  of  the  palate  and  the  uvula. 

§ 1872.  The  infraorbitar  nerve  ( N . infraorbitalis ),  the  second  of  the 
two  branches  in  winch  the  superior  maxillary  nerve  divides,  is  di- 
rected from  behind  forward,  from  within  outward,  and  from  above 
downward,  in  the  spheno-maxillary  fissure,  and  goes  to  the  infra-orbital 
canal. 

But  before  entering  into  this  canal,  it  sends  off  a considerable 
branch  called  the  dentar  or  posterior  superior  alveolar  nerve  ( R.  den- 
talis,  s.  alveolaris  posterior  superior).  This  nerve  divides  sometimes 
even  at  its  origin,  sometimes  afterward,  into  two  branches,  an  anterior 
which  is  smaller,  and  a posterior  which  is  larger. 

The  posterior  descends  on  the  posterior  part  of  the  external  w7all  of 
the  maxillary  sinus,  below  the  temporalis  muscle,  which  enters  into 
this  cavity  through  its  posterior  wall,  is  distributed  in  its  mucous  mem- 
brane, ( 1)  and  there  anastomoses  with  the  anterior  dentar  nerve.  It 
terminates  by  some  superficial  ramifications  which  go  to  the  buccinator 
muscle,  and  by  deeper  twigs  which  enter  into  small  canals  grooved  in 
the  posterior  part  of  the  body  of  the  superior  maxillary  bone,  and  pene- 
trates into  the  roots  of  the  three  large  posterior  molar  teeth.  Each  root 
receives  one  of  them.  We  see  one  of  them  also  between  each  two 
molar  teeth,  which  goes  into  the  gum. 

The  anterior  branch  is  distributed  principally  in  the  upper  and  pos- 
terior part  of  the  buccinator  muscle. 

After  giving  off  the  upper  and  posterior  dentar  nerve,  the  infra- 
orbitar nerve  enters  into  the  infra-orbitar  canal. 

In  passing  through  this  canal  it  usually  gives  off,  sometimes  sooner 
and  sometimes  later,  several  branches,  but  always  one  at  least,  which 
is  larger  than  the  others  even  when  they  exist  ; these  are  the  anterior 
dentar  nerves  ( N . dentales  anteriores)  which  enter  into  the  superior 
maxillary  bone,  send  some  filaments  into  the  nose  at  the  anterior  part 
of  the  inferior  turbinated  bone,  anastomose  by  several  filaments  with 
the  posterior  dentar  nerves,  pass  forward  on  the  roots  of  the  anterior 
teeth,  and  terminate  by  ramifications  which  go  to  the  incisors,  the  ca- 

(1)  Bock  asserts  that  the  nerve  is  not  distributed  to  the  membrane  of  the  maxillary 
sinus  ; but  we  have  several  times  clearly  seen  filaments  arising  from  it, 

Vol.  III.  10 


70 


DESCRIPTIVE  ANATOMY. 


nine,  and  the  anterior  molar  teeth,  and  to  the  gum.  Those  which  be- 
long to  theincisors  and  the  canine  teeth  arise  directly  from  the  anterior 
dentar  nerve  ; those  of  the  anterior  molar  teeth  from  the  union  of  this 
nerve  with  the  posterior  dentar  nerve. 

The  infra-orbitar  nerve  then  emerges  from  the  canal  through  the 
infra-orbitar  foramen,  within  which  it  divides  into  two  principal 
branches,  an  internal  and  an  external,  and  sometimes  even  in  all  the 
other  subordinate  branches.  It  thus  comes  on  the  face,  where  it 
divides  into  a considerable  number  of  ramifications,  which  terminate  in 
the  skin  and  the  muscles  of  the  nose  and  upper  lip,  and  anastomose 
with  those  of  the  first  principal  branch  of  the  fifth  pair,  and  also  with 
some  filaments  of  the  facial  nerve. 

The  two  principal  branches  usually  subdivide  into  six  or  seven 
twigs,  which  may  be  distinguished  into  superior , anterior , and  in- 
ferior. 

1st.  Superior  branch.  There  is  usually  only  one  superior  twig, 
the  inferior  palpebral  nerve  (N.  palpebralis  inferior).  This  nerve, 
the  first  given  off  by  the  infraorbitar  nerve,  from  which  it  is  some- 
times separated  even  within  this  canal,  and  which  often  emerges 
through  a special  foramen  situated  more  internally  than  the  infra- 
orbitar,  immediately  ascends  from  without  inward  towards  the  lower 
part  of  the  orbicularis  palpebrarum  muscle,  and  divides  into  an  external 
and  an  internal  twig. 

The  external  goes  outward  towards  the  external  angle  of  the  eye, 
on  the  lower  part  of  the  orbicularis  palpebrarum,  and  gives  off  fila- 
ments to  this  muscle.  It  anastomoses  with  those  of  the  internal  twig, 
and  with  the  temporal  branches  from  the  facial  nerve. 

The  internal  goes  to  the  inner  angle  of  the  eye,  gives  a twig  to  the 
skin  of  the  nose  which  descends  to  the  end  of  this  organ,  where  it 
anastomoses  with  the  nasal  twig  of  the  first  principal  branch  of  the 
fifth  pair.  It  afterwards  anastomoses  in  the  lower  eyelid  with  the 
external  twig  and  with  a filament  of  the  infra-trochlear  nerve,  and  ter- 
minates in  the  orbicularis  palpebrarum  muscle,  the  integuments  of  the 
lower  eyelid,  the  caruncula  lachrymalis,  and  the  lachrymal  sac. 

2d.  Anterior  or  nasal  twigs.  The  twigs  which  go  forward,  and 
also  at  the  same  time  a little  outward,  are  the  superficial  or  cutaneous 
nasal  nerves  ( N . nasales  superficiales),  which  may  be  distinguished 
into  an  internal  superior , and  an  external  inferior. 

The  internal  superior , generally  the  smaller,  is  reflected  upward 
under  the  levator  palpebræ  superioris  muscle,  often  gives  origin  to  the 
preceding,  and  then  divides  into  two  or  three  filaments  which  proceed 
forward  below  this  muscle  along  the  centre  of  the  nose,  send  their  rami- 
fications into  the  levator  labii  superioris  alæque  nasi,  and  the  depressor 
alæ  nasi  muscles,  and  the  integuments  of  the  middle  and  inferior  parts 
of  the  nose.  They  extend  to  the  back  and  tip  of  this  organ,  and  anas- 
tomose in  the  latter  place  with  the  nasal  twig  of  the  first  principal 
branch  of  the  fifth  pair. 


OF  THE  NERVOUS  SVSTEM. 


71 


The  external  and  inferior  descends  under  the  levator  labii  superioris 
muscle,  often  sends  an  ascending  filament  to  the  lower  eyelid  and  to 
the  lower  part  of  the  orbicularis  palpebrarum  muscle,  then  continues 
its  course  from  above  downward,  often  receives  a filament  from  the 
preceding,  goes  forward  to  the  ala  of  the  nose  above  the  levator  labii 
superioris  aloeque  nasi  muscle,  sends  ramifications  to  this  muscle  and 
to  the  middle  and  upper  parts  of  the  orbicularis  oris,  and  terminates  at 
the  lower  part  of  the  septum  and  of  the  top  of  the  nose,  where  it  anas- 
tomoses with  the  nasal  twig  of  the  first  principal  branch  of  the  fifth 
pair. 

3d.  Descending  or  labial  tu-igs.  The  descending  twigs  are  generally 
three  or  four  superior  labial  nerves  (N.  labiales  superiores ),  they  suc- 
ceed one  another  from  before  backward.  They  are  distinguished  into 
internal , middle , and  external.  All  descend  from  before  backward, 
covered  by  the  levator  labii  superioris  muscle,  are  distributed  in  this 
muscle,  the  skin  of  the  upper  lip,  the  corresponding  part  of  the  orbicu- 
laris oris,  and  the  lower  part  of  the  zygomatici  and  the  buccinator 
muscles.  They  even  penetrate  through  the  orbicularis  oris  muscle, 
and  go  to  the  buccal  membrane  and  the  glands  of  the  upper  lip. 

3d.  We  frequently  find  also  an  external  twig  of  the  infraorbitar 
nerve,  the  external  palpebral  nerve.  This  very  small  twig  passes 
through  the  levator  labii  superioris  muscle,  goes  outward,  where  some 
of  its  filaments  are  distributed  in  the  orbicularis  palpebrarum  muscle, 
and  others  anastomose  with  filaments  of  the  facial  nerve. 

C.  THIRD  PRINCIPAL  BRANCH. 

§ 1873.  The  third  principal  branch , the  inferior  or  posterior  branch 
of  the  fifth  pair,  the  inferior  maxillary  nerve  (22.  quinti  paris  tertius , s. 
inferior , s.  posterior,  s.  nervus  infra-inaxillaris),(  1 ) which  is  by  far  the 
largest,  arises  from  the  lower  and  posterior  part  of  the  ganglionnary 
plexus,  and  is  formed  principally  by  the  small  anterior  portion,  whence 
Palletta(2)  considers  it  a distinct  nerve.  It  is  the  shortest  of  the  three 
within  the  skull,  and  goes  from  above  downward,  and  slightly  also 
forward  and  outward,  and  enters  the  round  foramen  of  the  sphenoid 
bone,  after  anastomosing  hi  this  course  with  some  inconstant  filaments, 
with  the  cavernous  ganglion  of  the  sympathetic  nerve.  (3) 

The  inferior  maxillary  nerve  is  distributed  to  the  muscles,  the  in- 
teguments, and  the  teeth  of  the  lower  jaw,  the  lower  lip,  the  lower 
salivary  glands,  and  the  tongue. 

It  is  covered  where  it  emerges  from  the  cranium,  by  the  pterygoideus 
externus  muscle,  and  soon  divides  into  two  large  branches,  an  upper 
and  anterior,  and  a lower  and  posterior.  This  bifurcation  however  is 


(1)  A.  F.  L.  Fitzau,  De  tertio  ramo  paris  quinti  nervorum  cerebri  s.  nervi  maxil - 
lari  inferiori,  Leipsic,  1811. 

(2)  De  nervis  crotaphitico  et  buccinator io,  Milan,  1784. 

(3)  Laumonier,  loc.  cit. — Munniks,  De  origine  nervi  intercost,  in  Ohs.  rar.,  Gro- 
ningen, 1805. 


72 


DESCRIPTIVE  ANATOMY. 


not  constant,  for  sometimes  the  twig  formed  by  the  two  branches 
comes  directly  from  the  trunk*. 

§ 1S74.  The  upper  anterior  branch  is  much  smaller  than  the  other, 
divides  soon  after  and  even  before  emerging  from  the  skull,  into  live 
twigs,  which  separate  from  each  other  like  rays.  They  are  the  mas- 
seteric., the  internal  and  external  deep  temporal,  the  buccal  and  the 
pterygoid  nerves. 

The  masseteric  nerve  {N.  massetericus ),  the  most  external,  which 
generally  arises  the  highest,  pursues  a transverse  direction  from  within 
outward,  directly  before  the  articular  surface  of  the  temporal  bone,  on 
the  outside  of  the  pterygoideus  externus  muscle,  where  it  sends  fila- 
ments to  the  ligaments  of  the  temporo-maxillary  articulation,  and  to 
the  lower  part  of  the  temporalis  muscle,  then  descends  from  within 
outward  between  this  muscle  and  the  pterygoideus  externus  muscle, 
goes  to  the  sigmoid  fissure  of  the  lower  maxillary  bone,  and  passing 
behind  the  tendon  of  the  temporalis  muscle,  glides  between  the  two 
layers  of  the  masseter,  in  which  it  is  almost  entirely  distributed. 

The  second  twig,  the  external  deep  temporal  nerve  (N.  temporalis 
profundus  externus ),  arises  farther  forward  and  inward,  often  comes 
from  the  preceding  or  from  the  buccal  nerve,  and  sometimes  from  a 
common  trunk  with  the  following.  It  goes  outward  under  the  ptery- 
goideus externus  on  the  temporalis  muscles,  commonly  anastomoses 
with  the  following  and  by  an  intermediate  filament,  and  goes  imme- 
diately upward  and  inward  to  enter  the  temporalis  muscle. 

The  third  twig,  the  deep  internal  temporal  (N.  temporalis  profundus 
internus),  is  generally  larger  than  the  preceding,  and  follows  the  same 
course.  It  is  distributed  also  in  the  temporalis  muscle,  but  also  sends 
some  anastomotic  filaments  to  the  buccal  nerves.  It  also  gives  off 
others  farther  forward  which  go  to  anastomose  with  the  cutaneous 
malar  and  with  the  lachrymal  nerve  on  the  outside  of,  and  sometimes 
even  within,  the  orbit  : the  existence  however  of  these  last  two  anas- 
tomoses has  been  doubted,  since  the  researches  of  Bock,  who  regards 
the  filaments  generally  considered  as  such,  as  ramifications  of  the 
arteries.(l) 

The  fourth  twig,  the  buccinator  or  buccal  nerve  ( N . buccinatorius ), 
is  usually  the  largest  of  the  five,  and  sometimes  the  trunk  of  the  three 
preceding.  It  goes  forward  between  the  two  pterygoidei  muscles  and 
through  the  external,  sends  filaments  to  these  two  muscles,  particu- 
larly the  externa],  arrives  at  the  lower  part  of  the  temporalis  muscle, 
then  descends  between  this  latter  and  the  pterygoideus  externus,  comes 
on  the  external  face  of  the  buccinator,  is  distributed  mostly  to  this 
muscle,  passes  through  it  to  send  some  filaments  to  the  membrane 
and  to  the  buccal  glands,  anastomoses  with  the  anterior  branches  of 
the  facial  nerve,  and  terminates  in  the  levator  and  depressor  anguli 
oris  muscles. 

(I)  Rock,  toe.  cil.,  p.  4-1. 


OF  THE  NERVOUS  SYSTEM, 


73 


The  fifth  twig,  the  pterygoid  nerve  (N.  pterygoidens),  is  the 
smallest.  It  arises  from  the  inner  part  of  the  superior  branch,  passes 
between  the  pterygoideus  extemus  and  peristaphylinus  muscles  and 
arrives  at  the  upper  part  of  the  pterygoideus  internus,  to  which  it  is 
entirely  distributed. 

§ 1875,  The  posterior  and  inferior  branch  is  much  larger  than  the 
preceding  and  the  proper  continuation  of  the  trunk,  divides  soon  after 
arising  into  three  twigs,  the  superficial  temporal , the  inferior  dentar, 
and  the  lingual  nerve. 

The  superficial  temporal  nerve  (JV.  temporalis  superficialis ) most 
generally  arises  by  two  more  rarely  by  three  roots,  and  still  more  rarely 
by  one.  Of  these  two  roots,  the  inferior,  the  smaller,  comes  from  the 
inferior  dentar  nerve  and  reunites  with  the  superior,  so  that  the  sphero- 
spinous  or  middle  cerebral  artery  passes  between  them. 

The  trunk  goes  from  within  outward  on  the  inside  of  the  temporo- 
maxillary  articulation  between  the  condyle  of  the  jaw  and  the  lateral 
ligament,  and  here  divides  in  five  or  six  branches.  Two  or  three  of 
these  branches  penetrate  from  without  inward  and  from  behind  for- 
ward in  the  parotid  gland,  and  anastomose  with  this  trunk  and  with 
some  ramifications  of  the  facial  nerve.  One  or  two  of  the  others, 
which  may  be  termed  the  nerves  of  the  external  auditory  passage  (N, 
meatus  auditorii  externi  inferior , s.  superior ),  go  backward,  pass 
through  the  anterior  wall  of  the  osseous  portion  of  the  auditory  pas- 
sage, and  pass  between  this  and  the  cartilaginous  portion;  Their  rami- 
fications are  distributed  some  in  the  integuments  of  the  inner  part  of 
the  external  ear,  and  others  in  those  of  the  auditory  passage.  We 
see  also  one  of  them  which  goes  to  the  membrane  of  the  tympa- 
num, glides  between  its  two  layers,  and  anastomoses  by  one  or  two 
filaments  with  the  cord  of  the  tympanum.(l) 

The  last  and  largest  branch  of  the  superficial  temporal  nerve  passes 
through  the  parotid  gland  to  the  external  ear,  and  terminates  in  the 
integuments  of  the  central  part  of  the  cranium  by  anastomosing  with 
some  filaments  of  the  great  occipital  and  the  frontal  nerve  of  the  first 
principal  branch  of  the  fifth  pair.  It  also  communicates  with  some 
filaments  of  the  external  lachrymal  twig  and  of  the  cutaneous  malar 
nerve  which  go  outward. 

The  other  two  nerves  given  off  by  the  posterior  and  inferior  branch 
of  the  infra-maxillary  nerve  at  first  form  only  'a  single  but  very  short 
trunk. 

The  inferior  dentar  nerve  ( N . alveolaris  maxillœ  inferioris,  N. 
maxillaris  inferior ),  which  is  situated  between  the  other  two  twigs  of 
the  posterior  branch  which  is  generally  the  largest  ramification  given 
off  by  the  trunk  of  the  inframaxillary  nerve,  sometimes  arises  by  two 
roots  which  embrace  the  internal  maxillary  artery.  It  descends  from 
within  outward  and  from  behind  forward,  first  between  the  two  ptery- 


(1)  Bock,  loc.  cit.,  p.  49. 


74 


DESCRIPTIVE  ANATOMY. 


goidei  muscles,  then  between  the  external  and  the  condyle  of  the  jaw. 
Near  its  origin  it  gives  off  a small  and  very  constant  branch,  the  mylo- 
hyoid nerve  (N.  mylo-liyoideus ),  which  descends  from  behind  forward 
in  a channel  grooved  in  the  inner  face  of  the  branch  of  the  jaw,  sends 
a twig  to  the  submaxillary  gland,  goes  towards  the  lower  face  of  the 
mylo-liyoideus  muscle,  proceeds  from  behind  forward  between  this 
muscle  and  the  anterior  belly  of  the  digastricus,  gives  some  filaments 
to  both  of  them  but  particularly  to  the  mylo-hyoideus  muscle,  and  after 
being  reflected  from  below  upward  on  the  lower  edge  of  the  lower 
jaw,  is  distributed  in  the  muscles  of  the  chin. 

The  trunk  of  the  inferior  dentar  nerve  proceeds  from  behind  forward 
in  the  inferior  dentar  canal.  But  it  generally  divides  on  entering  into 
two  branches,  a superior  which  is  smaller,  the  dentar  nerve  ( N . den- 
talis ),  and  an  inferior  and  larger,  the  mental  nerve  {11.  mentalis ) ; these 
proceed  at  the  side  of  each  other,  and  communicate  by  numerous  anas- 
tomosing filaments. 

The  dentar  branch  is  situated  below  the  teeth,  and  sends  a filament 
to  each  of  them  and  to  each  root  of  the  molar  teeth.  All  these  fila- 
ments arise  farther  back  than  the  teeth  to  which  they  proceed  : be- 
tween each  two  teeth  it  sends  a filament  to  the  gum. 

The  mental  branch  emerges  through  the  mental  foramen.  It  soon 
divides  under  the  levator  anguli  oris  muscle  into  two  twigs,  the  infe- 
rior labial  nerves  (N.  labiales  inferiores ),  the  internal  of  which  is  larger 
in  a greater  or  less  degree  than  the.  external: 

The  direction  of  the  external  is  upward  ; it  sends  some  filaments  to 
the  levator  anguli  oris  muscle,  but  principally  to  the  lower  part  of  the 
orbicularis  oris,  the  glands  of  the  lower  lip  and  the  buccal  membrane, 
and  anastomoses  with  some  filaments  from  the  inferior  branches  of  the 
facial  nerve. 

The  internal , covered  by  the  depressor  labii  inferioris  muscle,  goes 
forward  and  upward,  sends  filaments  to  this  muscle,  to  the  levator 
menti,  the  central  part  of  the  orbicularis  oris,  the  skin  of  the  chin,  the 
glands  of  the  lower  lip,  and  the  buccal  membrane,  and  anastomoses 
with  the  marginal  branch  of  the  facial  nerve. 

The  lingual  nerve  ( N . lingualis , s.  gustatorius ),  the  most  anterior  of 
the  three  twigs  of  the  lower  and  posterior  branch  of  the  inframaxillary 
nerve  is  between  the  other  two  in  respect  to  size.  It  arises  farther 
inward  than  they,  and  is  frequently  united  to  a considerable  extent  in  a 
common  trunk  with  the  preceding.  It  descends  with  it  from  behind 
forward,  usually  on  the  inside  of  the  internal  maxillary  artery,  sepa- 
rates from  the  inferior  dentar  nerve  and  goes  inward,  receives  before 
the  palatostaphylinus  and  pterygostaphylinus  muscles,  and  behind  the 
pterjrgoideus  externus,  the  cord  of  the  tympanum,  which  unites  with  it 
at  a very  acute  angle,  then  passes  before  the  inferior  dentar  nerve,  some- 
times sends  to  the  pterygoideus  internus  muscle  a filament  which  is 
often  detached  above  the  anastomosis  with  the  cord  of  the  tympanum, 
enters  between  the  pterygoideus  internus  and  the  ascending  branch  of 
the  jaw,  and  passing  above  the  submaxillary  gland,  gives  to  it  as  high 


OF  THE  NERVOUS  SYSTEM. 


75 


as  the  angle  of  the  jaw  several  considerable  filaments,  which  come 
sometimes  directly  from  its  trunk,  sometimes  from  a small  ganglion 
which  it  forms  on  it,  and  which  is  called  the  maxillary  ganglion  ( gan- 
glion inaxillare.) 

These  filaments  are  distributed  principally  in  the  gland.  Generally 
however  one  of  them  emerges  from  it,  descends  on  the  hyoglossus 
muscle,  anastomoses  with  a branch  of  the  lingual  nerve,  and  termi- 
nates in  the  genio-glossus  muscle. 

The  trunk  of  the  lingual  nerve  then  goes  forward  between  the  hyo- 
glossus and  mylo-hyoideus  muscles,  passes  between  the  sublingual 
gland  and  the  hyoglossus  muscle  having  before  it  the  excretory  duct 
of  the  submaxillary  gland,  anastomoses  by  several  considerable  fila- 
ments which  come  from  its  inner  side  with  the  hypoglossal  nerve,  sends 
some  which  are  very  minute  to  the  buccal  membrane  and  larger  ones 
to  the  sublingual  gland,  and  divides  into  seven  or  eight  branches  which 
proceed  from  behind  forward  and  from  below  upward  between  the 
styloglossus  and  genio-hyoideus  muscles.  These  branches  separate 
like  the  sticks  of  a fan,  and  go  principally  to  the  edges  and  tip  of  the 
tongue  and  are  there  distributed  by  minute  filaments  in  the  skin 
of  this  organ. 


IX.  INTERNAL  MOTOR  NERVE. 

§ 1876.  The  superior  or  internal  motor  nerve,  the  pathetic , the 
fourth  pair,  the  internal  oculo-muscular  nerve  (N.  oculo-muscularis  su- 
perior, s.  minimus,  s.  musculi  oculi  obliqui  superioris,  s.  par  cerebrale 
quartum,  s.  N.  patheticus) ,{l)  the  smallest  cerebral  nerve,  generally 
arises  by  an  anterior  and  a posterior  root,  each  composed  of  one  fila- 
ment about  the  same  size.  They  are  frequently  half  an  inch  apart, 
but  united  by  cellular  tissue.  They  arise  directly  behind  the  external 
half  of  the  posterior  part  of  the  tubercula  quadrigemina  from  the  an- 
terior and  external  part  of  the  upper  face  of  the  cerebral  valve,  so  that 
the  anterior  arises  from  some  transverse  medullary  fibres  which  cover 
the  valve  in  this  place,  and  which  unite  them  on  the  median  line  with 
those  of  the  opposite  side.  This  nerve  seldom  has  three  roots  and  still 
more  rarely  one  only. 

After  arising,  it  goes  downward  and  a little  forward,  first  on  the 
upper  extremity  of  the  anterior  prolongations  of  the  cerebellum,  then 
about  two  lines  from  the  anterior  edge  of  the  occipital  protuberance, 
first  on  the  lateral  and  then  on  the  lower  face  of  the  cerebral  peduncle. 
After  proceeding  much  farther  within  the  skull  than  any  other  ence- 
phalic nerve,  it  comes  to  the  posterior  clinoid  process.  There  it  enters 
into  a special  canal  of  the  dura-mater,  the  internal  wall  of  which  is 
very  thin  and  separates  it  from  the  cavernous  sinus,  usually  anasto- 
moses there  with  the  first  branch  of  the  trifacial  nerve  by  a small  fila- 


(1)  Zinn,  loc.  cit. — Scemmerringr,  in  Demours,  loc.  cit.,  vol.  iv.  p.  31,  pi.  vi.,  fig1.  1. 


76 


DESCRIPTIVE  ANATOMY. 


ment,  and  is  situated  first  below  the  common  motor  and  the  ophthal- 
mic nerves.  At  the  sphenoidal  fissure  it  is  situated  above  the  first  of 
these  two  nerves,  enters  into  the  orbit  through  the  upper  and  internal 
part  of  this  fissure,  and  its  direction  there  is  from  behind  forward  and 
from  without  inward  directly  under  the  periosteum,  attended  by  the 
frontal  twig  of  the  ophthalmic  branch  of  the  fifth  pair,  and  enlarges 
much  in  this  course.  Finally  it  enters  the  obliquus  oculi  superior 
muscle  at  about  its  centre. 


X.  COMMON  MOTOR  NERVE. 

§ 1877.  The  common  motor  nerve,  the  common  motor  of  the  eye,  the 
third  pair,  the  common  oculo-muscular  nerve  (N.  oculo-muscularis  in- 
ferior, s.  médius,  s.  oculo-motorius  communis,  s.  par  tertium),{\ ) a con- 
siderable trunk  generally  the  fourth  in  size  and  rarely  the  third  among 
the  encephalic  nerves,  arises  about  two  lines  before  the  anterior  edge 
of  the  annular  protuberance  on  the  inner  face  of  the  cerebral  peduncle 
about  two  lines  above  its  lower  edge,  at  the  place  where  the  gray 
cribriform  plate  which  covers  the  inner  face  of  the  peduncle  com- 
mences. It  even  arises  in  great  part  from  this  layer.  Some  smaller 
filaments  coming  from  near  the  internal  edge  of  the  lower  face  of 
the  cerebral  peduncle  usually  join  this  root,  which  is  single  and  very 
large. 

It  is  however  easy  to  follow  the  origin  of  the  nerve  farther  upward 
and  backward,  for  beyond  the  point  where  it  leaves  the  annular  pro- 
tuberance it  is  covered  anteriorly  only  by  a very  thin  layer  of  gray 
substance  of  which  we  perceive  no  trace  posteriorly.  When  this  sub- 
stance is  removed,  when  the  annular  protuberance  is  divided,  turned 
from  above  downward,  and  carefully  cut  longitudinally  on  the  median 
line,  we  observe  that  a medullary  layer  commences  at  the  place  where 
the  nerve  emerges,  continues  with  its  fibres,  and  terminates  like  a fan 
upward  and  a little  forward,  forms  a fasciculus  which  is  rounded  pos- 
teriorly although  straight  at  first,  and  curves  from  below  upward. 

The  anterior  and  flat  part  of  this  layer  extends  to  the  bottom  of  the 
groove  existing  between  the  two  cerebral  peduncles.  Its  posterior 
parts  are  arranged  in  fasciculi,  converge  from  before  backward,  and 
are  blended  at  their  posterior  part.  The  anterior  part,  is  loose,  but  in 
order  to  see  the  posterior  we  must  separate  the  anterior  half  of  the 
annular  protuberance  and  turn  over  the  two  folds.  The  posterior  part 
of  this  medullary  layer  then  rises  directly  below  the  floor  of  the  aque- 
duct of  Sylvius. 

The  two  nerves  are  at  first  attached  to  each  other  by  their  inner 
faces,  so  that  they  slightly  resemble  the  arrangement  of  the  optic 
nerves.  After  leaving  this  point,  where  they  are  detached  from  the 
encephalon,  they  proceed  from  within  outward  and  from  before  back- 

(1)  Zinn,  loc.  cit. — Scemmerring,  in  Dcmours,  loc.  cit.,  vol.  iv.  p.  34,  pi.  vi.  fig.  2. 


OF  THE  NERVOUS  SYSTEM. 


77 


ward,  arrive  at  the  external  wall  of  the  cavernous  sinus,  are  situated 
within  and  above  the  first  branch  of  the  trifacial  and  the  superior  motor 
nerves  ; then  changing  this  direction  below  and  on  the  outside  of  these 
nerves  they  pass  through  the  dura- mater  which  closes  the  sphenoidal 
fissure,  and  enter  the  orbit  with  the  external  motor  and  the  nasal  branch 
of  the  trifacial  nerve. 

Before  passing  through  the  dura-mater,  the  common  motor  nerve  is 
divided  into  a superior  and  an  inferior  branch. 

The  superior , the  smaller,  goes  inward  and  forward,  passes  on  the 
optic  nerve  and  the  nasal  twig  of  the  ophthalmic  branch,  anastomoses 
with  this  latter,  sends  its  twigs  into  the  rectus  oculi  superior  muscle, 
and  passes  through  it  to  be  distributed  in  the  levator  palpebræ  superi- 
oris  muscle. 

The  inferior  is  much  larger  than  the  preceding,  and  passes  below 
and  on  the  outside  of  the  optic  nerve,  between  it  and  the  rectus  oculi 
inferior  muscle.  It  usually  divides  into  three  twigs,  an  internal , which 
is  larger,  which  goes  to  the  rectus  internus  muscle  ; a middle , which 
is  shorter,  for  the  rectus  inferior  muscle,  and  an  external  inferior 
branch,  which  is  the  longest  and  thinnest,  and  which  goes  to  the  ob- 
liquus  inferior  muscle,  and  the  lenticular  ganglion. 

This  latter  gives  off  near  its  origin  a short  filament,  which,  situated 
on  the  outside  of  the  optic  nerve,  goes  to  the  posterior  extremity  of  the 
lenticular  ganglion,  and  forms  its  short  root.  This  filament  is  always 
composed  of  several  threads,  arises  more  rarely  from  the  lower  branch, 
but  sometimes  also  it  comes  at  the  same  time  from  the  external  twig, 
from  the  middle,  and  eveir  from  the  trunk  of  the  lower  branch.(l) 

Sometimes,  but  very  rarely,  the  long  root  of  the  lenticular  ganglion 
also  arises  from  the  common  motor  nerve.(2) 

XI.  OPTIC  NERVE. 

§ 1878.  The  optic  or  ocular  nerve,  the  second  pair  (N.  opticus , s. 
visorius , s.  par  secundum ),  the  largest  of  the  encephalic  nerves  arises 
by  a broad  and  flat  portion  from  the  posterior  part  of  the  external  face, 
and  also  from  the  upper  face  of  the  optic  bed  and  the  tubercula  quad- 
rigemina.  Its  anterior  part,  which  is  the  broadest,  leaves  the  upper 
face  of  the  optic  bed,  from  the  substance  of  which  it  is  easily  dis- 
tinguished on  account  of  the  transverse  direction  of  its  medullary 
fibres,  to  pass  on  its  anterior  and  external  tubercle.  The  posterior 
passes  below  the  posterior  and  external  tubercle,  and  is  attached  in 
this  place  to  the  tubercula  quadrigemina,  particularly  the  posterior,  by 
a medullary  band,  which  goes  forward  from  these  latter,  passing  below 
the  posterior  and  external  tubercle  of  the  optic  bed.  Thence  the  optic 
nerve  proceeds  from  behind  forward  and  from  without  inward,  and  de- 
scends on  the  lower  face  of  the  cerebral  peduncle,  with  which  it  is  so 


43. 


(1)  Bock,  loc.  cit.,  p.  12. 

(2)  Morgagni,  Ep.  anat .,  xvi.  § 59- — Meckel,  De  quinto  pare , § 

VOL,  III.  11 


78 


DESCRIPTIVE  ANATOMY . 


closely  connected  that  we  must  admit  that  it  partly  arises  from  this 
prolongation,  although  separated  from  it  in  almost  all  its  extent  by  the 
pia-mater.  It  gradually  becomes  narrower,  but  thicker  and  more 
rounded,  and  unites  at  an  obtuse  angle  with  that  of  the  opposite  side 
on  the  median  line,  on  the  lower  face  of  the  cerebrum,  below  the  floor 
of  the  third  ventricle.  The  union  is  so  intimate  that  the  two  nerves 
form  only  one  medullary  mass.  This  mass  itself  has  the  form  of  an 
elongated  square,  which  differs  in  different  subjects,  as  is  indicated 
in  Morgagni(l)  and  Wenzel, (2)  nor  has  it  always  the  same  volume. (3) 
It  receives  above  some  medullary  fibres  from  the  floor  of  the  third  ven- 
tricle, so  that  we  are  authorized  to  think  that  the  optic  nerve  partially 
arises  from  this  point. 

After  this  union  the  two  optic  nerves  separate  and  go  forward  and 
outward.  Hence,  when  we  view  their  place  of  union  and  their  an- 
terior and  posterior  parts,  they  represent  the  form  of  an  X or  of  a cross. 
Thus,  their  decussation  has  been  termed  the  intercrossing  (chiasma). 
It  is  very  rare,  and  perhaps  never  the  case,  that  the  two  nerves  do  not 
unite, (4)  or  that  by  an  arrangement,  perhaps  the  opposite  of  the  pre- 
ceding, a small  pointed  protuberance  comes  from  the  anterior  edge  of 
the  decussation.(ö) 

Opinions  vary  in  regard  to  the  manner  in  which  the  optic  nerves 
unite.  Some  assert  that  they  are  only  fitted  to  each  other,(6)  others 
that  they  entirely  intercross,  and  that  of  the  right  eye,  for  instance, 
passes  to  the  left  side  of  the  body  behind  the  decussation.(7)  Finally, 
some  think  that  there  is  only  a partial  decussation,  an  intercrossing  of 
most  of  the  fibres, (8)  that  the  external  fibres  of  each  nerve  are  situated 
on  the  same  side  of  the  body  before  as  behind  the  decussation,  while 
the  internal  intercross  with  the  corresponding  fibres  of  the  opposite 
side,  and  pass  to  the  other  side  of  the  body.  (9) 

Those  who  maintain  the  first  hypothesis,  assert, 

1st.  That  on  examining  the  decussation  in  the  recent  state,  the 
fibres  of  the  nerve  are  seen  to  pass  through  its  external  edge,  but  do 

(1)  Ep.  anat.,  xvi.  § 13. 

(2)  Depenit,  struct,  cerebri,  p.  110. 

(3)  Ibid. 

(4)  Vesalius,  De  corp.  hum.  fab.  1.  iv.  c.  iv. 

(5)  Scemmerring,  in  Nœthig,  De  decussatione  nervorum  opticorum,  Mayence, 
1780. 

(6)  Gallen,  De  util,  part.,  lib.  x.  c.  xii. — Also  a great  number  of  his  successors, 
mentioned  in  Nœthig.— Zinn,  Desc.  oc.  hum.,  Gottingen,  1765,  p.  190. — Vicq-d’Azyr, 
in  the  Mém.  de  Paris,  1781,  p.  554. — Meckel,  in  Haller,  Grundriss,  p.  386. 

(7)  This  opinion  was  supported  before  Galen,  as  he  refutes  it  ( loc . cit.)  ; those  who 
have  defended  it  since,  are  cited  by  Morgagni  (Ep.  anat.)  and  by  Scemmerring,  in 
Nœthig,  loc.  cit.,  and  Denksder  Münchner  Akad..  1808,  p.  60. 

(8)  Michælis,  TJeber  die  Durchkreuzung  der  Sehnerven  ; in  Grosse,  Magazin  zur 
Naturgeschichte  des  Menschen,  vol.  ii.  part  i.  p.  149. 

(9)  Ackermann,  in  the  Med.  bibl.  of  lilumenbach. — Wenzel,  Locus  unionis  ner- 
vorum opticorum  ; in  De  pen.  sir.  cereb.,  cap.  xi.  p.  109. 


OF  THE  NERVOUS  SYSTEM. 


79 


-sot  leave  their  side,  while  the  middle  part  is  absolutely  homogeneous, 
and  presents  no  trace  of  fibrous  structure^  1) 

2d.  That  the  two  optic  nerves  have  been  found  entirely  distinct  from 
each  other,  and  the  sight  was  unimpaired. (2) 

3d.  That  where  the  optic  nerve  wasted  after  the  loss  of  an  eye,  the 
change  in  the  texture  was  seen  only  in  the  nerve  of  the  same  side,  be- 
hind the  decussation, (3)  and  that  it  is  very  easy  to  distinguish  in  this 
latter  the  two  nerves  from  each  other,  by  their  color  and  other  proper- 
ties.(4) 

The  partisans  of  the  second  opinion  state, 

1st.  The  normal  appearance. (5) 

2d.  Those  cases  where  the  origin  of  one  optic  nerve,  or  the  part  of 
the  two  nerves  behind  the  decussation  has  been  found  unusually  large 
or  small,  and  the  nerve  of  the  opposite  side  presented  the  same  charac- 
ter before  the  decussation, (6)  while  the  sight  was  unaffected. 

3d.  The  cases  in  which  the  disease  of  the  nerve  before  the  decussa- 
tion extended  behind  it  only  to  the  .nervous  cord  of  the  opposite  side, 
and  affected  even  the  corresponding  cerebral  portions  of  this  side.(7) 
4th.  The  analogous  cases  where  the  origin  of  one  of  the  two  nerves 
was  affected,  and  the  functions  of  the  eye  of  the  opposite  side  were 
deranged.(8)  Sometimes  only  this  origin  was  diseased,  and  not  the 
portion  of  the  nerve  on  the  other  side  of  the  decussation. (9) 

5th.  The  analogy  with  several  animals,  particularly  with  most 
fishes,  the  nerves  of  which  evidently  intercross  and  enter  each  other. 
The  third  hypothesis  is  supported, 

1st.  By  the  anatomical  examination  of  the  parts  in  the  normal 
state. (10) 


(1)  Vicq-d’Azyr,  loc.  cit. — Wenzel,  p.  Ill,  115.  This  anatomist  admits  that  a 
small  portion  of  the  inner  part  proceeds  to  the  opposite  side  before  they  unite  ; but 
as  he  expressly  remarks  that  he  has  been  unable  to  discover  any  fibre  in  this  in- 
ternal part,  the  preceding'  sentence  does  not  favor  the  decussation,  since  the  direc- 
tion he  allows  to  the  fibres  is  only  that  of  the  whole  nerve. — Caldani  (Mem.  delle 
soc.  ital.,  vol.  xii.  part  ii.  p.  28)  has  found  the  optic  nerves  united  behind  the  decus- 
sation by  a transverse  medullary  band. 

(2)  Vesalius,  loc.  cit. — Nicolas  de  Janua,  in  Caldani,  Opusc.  anat .,  Padua,  1803, 
p.  40. 

(3)  Vesalius,  loc.  cit. — Cesalpino,  in  Riolan,  Anlhopogr .,  1.  iv. — Cheselden,  in  the 
Phil,  trans. — Santorini,  Obs.  anat.,  c.  iii.  p.  63,  64. — Meckel,  in  Haller,  Grundriss , 
p.386. — Caldani,  Opusc.  anat.,  p.  33  and  35:  two  cases. — Id., ' in  Mem.  delle  soc  ital., 
vol.  xii.  plate  ii.  p.  27.— Burns,  Anatomy  of  the  head  and  neck,  Edinburgh,  1811, 
p.  359. 

(4)  Santorini,  loc.  cit. 

(5)  Petit,  in  the  Mém  de  Paris,  1736,  p.  7. — Sœmmerfing,  loc.  cit. 

(6)  Sœmmerring,  loc.  cit.  Several  cases. 

(7)  Michælis,  loc.  cit.,  p.  145. — Caldani,  loc.  cit.,  p.  35. — Wenzel. 

(8)  Valsalva,  in  Morgagni,  Ep.  anat.,  xiii.  p.  115.  obs.  iii. 

(9)  Wenzel,  loc.  cit.,  p.  125. 

(10)  Caldani,  Opusc.  anat.,  p.  37.  tab.  ii.  fig.  4.  The  simple  maceration  in  water, 
or  immersion  in  sulphuric  acid  and  vinegar,  gave  no  result  ; but  this  is  not  the 
case  with  nitric  acid  after  the  neurilemma  was  removed.  Caldani  has  observed, 
eight  times  in  this  manner,  that  the  external  nervous  fibres  went  directly  to  the  eye 
of  the  same  side,  and  the  internal  to  that  of  the  opposite  side,  that  consequently  these 
latter  intercrossed,  and  that  even  the  fasciculi  visibly  divided  into  several  branches. 


so 


DESCRIPTIVE  ANATOMY. 


2d.  By  those  pathological  cases  where  one  eye  being  destroyed  and 
its  nerve  affected,  the  external  fibres  of  the  diseased  nerve  and  of  the 
healthy  nerve,  remained  each  on  their  side  before  and  behind  the  de- 
cussation, while  the  internal  fibres  of  the  healthy  eye  passed  through  it 
to  go  to  the  opposite  side,  where  they  formed  the  internal  fibres  of  the 
nerve  of  this  side,  and  the  internal  fibres  of  the  diseased  nerve  also 
passed  to  the  healthy  side,  although  less  evidently,  at  least  in  some 
cases.(l) 

3d.  By  the  cases,  where  after  the  disease  of  an  eye  and  of  its  optic 
nerve,  the  decussation  and  the  nerve  of  the  same  side  behind  it,  were 
wasted. (2) 

4th.  By  the  cases  of  the  loss  of  an  ej'e  with  the  affection  of  only 
one  optic  nerve  before  the  decussation  and  of  the  opposite  nerve,  or  of 
both,  behind  this  point. (3)  This  fact  really  seems  to  favor  the  hypo- 
thesis of  a partial  decussation,  since  different  physiologists  think  it 
cannot  be  explained  otherwise,  and  more  so,  because  in  many  cases 
where  the  two  nerves  were  wasted  behind  the  decussation,  that  of  the 
healthy  eye  was  found  unusually  large. (4) 

When  all  these  pathological  facts  are  duly  considered,  we  must 
admit  that  they  do  not  prove  positively  either  of  the  three  opinions,  in- 
asmuch as  the  dissection  of  the  healthy  parts  has  not  demonstrated 
the  fact  of  the  decussation.  In  fact.,  they  may  be  explained  satisfac- 
torily by  saying  that  the  substance  of  the  two  nerves  is  so  blended  in 
the  decussation,  that  these  nervesdonot  partially  or  wholly  cross, and  still 
less  are  they  placed  one  against  the  other,  but  they  properly  arise  from 
this  common  substance  formed  by  the  union  of  the  two  optic  bands 
( tracius  optici ),  which  opinion  differs  much  from  that  of  a partial  de- 
cussation. The  differences  of  the  pathological  phenomena,  authorize 
the  adoption  of  this  hypothesis,  as  this  alone  explains  them  very  well. 
We  may  then  consider  as  accidental,  that  where  the  optic  nerve  is 
diseased  to  the  decussation,  the  alteration  is  observed  on  the  other  side 
of  this  union,  on  the  cord  of  the  same  side,  on  that  of  the  opposite  side, 
or  on  both  at  once.  This  intimate  union  of  the  two  portions  of  the 
optic  nerves  between  their  origin  and  decussation,  is  rendered  very 
probable  by  what  we  have  remarked,  and  which  had  been  seen  before 
us  by  Morgagni, (5)  Michaelis, (6)  Bichat, (7)  and  Wenzel, (8)  that 
when  the  optic  nerve  had  wasted  and  had  been  gray  for  a long  time 

Wenzel  has  once  found  in  a subject  whose  sight  was  not  affected,  some  gray  sub- 
stance in  the  centre  of  the  decussation  ; the  interna)  fibres  of  the  two  nerves  evi- 
dently passed  through  this  substance  to  intercross  (toc.  cit,  p.  118). 

(1)  Wenzel,  113,  217. 

(2)  Walter,  Uebcr  die  Einsavgung  und  die  Durchkreuzung  der  Sehnerven, 
Berlin,  1794,  p.  97. 

(3)  Ackermann,  loc.  cit. — This  has  been  seen  in  most  cases. 

(4)  Morgagni,  Epist.  anat.,  xviii.  40. — Michælis,  loc.  cit.,  p.  145. — Wenzel,  p.  125. 

(5)  Epist.  anat.,  xviii.  40. 

(6)  Loc.  cit.,  p.  146. 

(7)  Anat.  descript.,  vol.  iii.  p.  153. 

(8)  Loc.  cit.  p.  1 12. 


OF  THE  NERVOUS  SYSTEM. 


SI 


either  before  or  behind  the  decussation,  the  decussation  itself  and  the 
portion  of  the  nerve  before  or  behind  it,  was  not  in  the  least  abnormal, 
and  when  the  contrary  occurred,  the  portion  separated  by  the  decus- 
sation from  that  first  affected  by  the  disease,  was  always  altered  much 
less  than  this  latter.  This  phenomenon  certainly  indicates  a great 
difference  and  a marked  distinction  between  the  posterior  part  of  the 
nerve,  including  the  decussation  and  the  anterior  portion,  and  the  more, 
as  when  the  portion  situated  before  or  behind  the  decussation  is  dis- 
eased, it  usually  presents  the  same  kind  of  alteration  in  all  its  extent. 

The  differences  between  the  pathological  phenomena,  mentioned  by 
us  above,  depend  perhaps  on  primitive  differences  of  structure.  This 
conjecture  seems  much  more  probable,  as  the  structure  of  the  nervous 
system,  notwithstanding  its  great  regularity,  nevertheless  frequently 
presents,  when  attentively  considered,  very  great  anomalies.  It  is 
then  possible,  that  as  in  other  organs  situated  on  the  median  line,  the 
union  is  sometimes  more,  sometimes  less  intimate,  sometimes  there 
is  merely  a juxta-posidon,  and  that  there  are  a series  of  successive 
states,  the  first  link  of  which  is  the  case  described  by  Sœmmerring,  in 
Noethig,  and  the  last,  that  mentioned  by  Vesalius,  although  Haller 
rejects  this  hypothesis.(l) 

Finally,  the  texture  of  the  optic  nerve  before  or  behind  the  decussa- 
tion, according  as  the  origin  of  the  nerve  or  the  eye  are  primitively 
affected,  proves  nothing  in  favor  of  either  of  these  three  opinions,  since 
in  some  cases  where  the  sense  of  vision  was  lost  in  both  eyes  at  the 
same  time,  one  of  the  nerves  was  much  thinner  than  the  other  behind 
the  decussation.(2) 

Finally,  according  to  our  own  observations,  this  partial  decus- 
sation is  very  probable;  some  at  least  of  the  differences  in  the  patholo- 
gical phenomena  may  then  be  easily  explained,  since,  when  the  inner 
part  of  the  optic  nerve  is  affected,  that  of  the  opposite  side,  and  when 
the  outer  part  is  diseased,  that  portion  of  the  same  nerve  behind  the 
decussation  presents  marks  of  disease. 

§ 1879.  The  two  optic  nerves  separate  on  leaving  the  decussation, 
and  pass  through  the  optic  foramina  into  the  cavity  of  the  orbits.  Here 
they  are  situated  between  the  recti  muscles  of  the  eye,  curve  and  be- 
come convex  outward.  When  near  the  eye  they  contract  very  much, 
pass  through  the  sclerotica  and  also  the  choroid  membrane,  and  termi- 
nate in  the  organ,  expanding  in  the  retina. 

They  are  first  covered  with  neurilemma  before  the  decussation. 
This  membrane  has  there  more  firmness  than  in  the  other  nerves,  and 
penetrates  within  them,  forming  distinct  sheaths.  The  optic  nerves 
differ  from  all  others,  not  only  because  they  reunite,  but  also  because 
they  are  intimately  enveloped  in  all  their  course  by  a fibrous  sheath, 
which  is  continuous  posteriorly  with  the  periosteum  of  the  orbit  and 
dura-mater,  anteriorly  with  the  sclerotica. 

(1)  El.  phys.  book  xvi.  vol.  v.  p.  752. 

(2)  Wenzel,  p.  115.  obs.  ii. 


S2 


DESCRIPTIVE  ANATOMY. 


XII.  OLFACTORY  NERVE. 

§ 1S80.  The  olfactory  nerve,  the  first  pair,  the  ethmoidal  nerve  (N. 
olfactorius,  s.  par  primum,  the  caruncula  of  the  ancients,  who  con- 
sidered the  optic  nerves  as  the  first  cerebral  pair),  is  situated  on  the 
lower  face  of  the  hemispheres  of  the  cerebrum,  in  a groove  which  is 
there  seen,  but  a few  lines  from  their  inner  edge.  It  goes  a little  ob- 
liquely from  without  inward,  so  that  the  cords  of  the  two  sides  are 
separated  anteriorly  only  by  the  crista  galli  process.  In  this  course  it 
advances,  on  the  body  of  the  sphenoid  bone  and  the  cribriform  plate  of 
the  ethmoid  bone,  covered  by  the  pia-mater,  which  extends  like  a 
bridge  from  one  edge  of  the  groove  in  which  it  is  situated,  to  the  other. 
This  groove,  however,  is  much  deeper  than  the  thickness  of  the  nerve, 
and  like  all  the  other  anfractuosities  of  the  cerebrum,  the  pia-mater 
exactly  covers  its  surface  in  all  parts. 

The  olfactory  nerve  arises  by  three  medullary  bands  or  roots,  from 
the  posterior  and  inner  part  of  the  anterior  lobe  of  the  cerebrum,  where 
this  latter  unites  to  the  posterior  lobe.  The  external  band  is  the  nar- 
rowest and  strongest.  Convex  posteriorly,  concave  anteriorly,  its 
direction  is  from  behind  forward,  from  without  inward,  and  from  above 
downward  in  the  fissure  of  Sylvius,  at  the  union  of  the  anterior  lobe 
with  the  posterior,  proceeds  at  first  almost  transversely,  then  descends 
nearly  perpendicularly,  and  reunites  with  the  internal  root  some  dis- 
tance from  the  posterior  extremity  of  the  lower  face  of  the  anterior 
lobe. 

The  middle  root,  the  shortest,  and  which  it  is  generally  more  correct 
to  consider  only  as  the  internal  portion  of  the  external  root,  arises  from 
the  centre  of  the  anterior  perforated  plate  or  even  directly  from  this 
plate  by  some  fibres  of  which  the  internal  are  concave  inward  and  the 
external  are  straight.  After  proceeding  from  one  to  two  lines,  it  unites 
to  the  external  root  and  gives  rise  to  a common  trunk  a line  and  a half 
large  and  very  broad,  the  direction  of  which  is  oblique  from  behind  for- 
ward and  from  without  inward. 

The  internal  root  is  from  one  to  four  lines  long.  It  comes  from  the 
internal  posterior  extremity  of  the  lower  face  of  the  anterior  lobe,  pro- 
ceeds obliquely  from  above  downward,  from  behind  forward,  and 
from  within  outward,  and  anastomoses  with  the  common  trunk  of  the 
others. 

All  these  roots  are  so  imbedded  in  the  gray  substance  that  we  per- 
ceive only  their  internal  faces,  and  we  cannot  demonstrate  them  in 
every  part  without  separating  them  by  art. 

Very  probably  all  the  gray  substance  in  which  they  are  imbedded 
should  be  regarded  as  a portion  of  the  cerebrum  which  is  connected 
Avith  the  origin  of  the  olfactory  nerve.  This  portion  is  oblong.  It  is 
continuous  outward  with  the  union  of  the  anterior  and  posterior  lobes, 
backAvard  Avith  the  anterior  perforated  or  cribriform  plate,  forward  at 
its  outside  and  inside  with  two  circumvolutions  Avliich  bound  the  fis- 


OF  THE  NERVOUS  SYSTEM. 


83 


sure  of  the  olfactory  nerve.  It  is  loose  at  its  centre  and  forms  the  pos- 
terior wall  of  this  fissure  within  which  it  projects. 

The  nerve  enlarges  much  from  behind  forward,  so  that  its  anterior 
extremity  is  two  or  three  times  thicker  than  its  origin. 

It  is  prismatic,  the  base  looks  downward,  the  two  lateral  faces  are 
turned  inward  and  outward,  and  the  upper  angle  is  the  most  acute. 

In  its  whole  extent  it  is  very  evidently  formed  of  gray  and  of  white 
substance  disposed  in  longitudinal  fibres  which  proceed  at  the  side  of 
each  other  and  interlace  together.  Its  anterior  and  enlarged  extre- 
mity called  the  bulb  of  the  olfactory  nerve  (bulb us  n.  olfactorii),  is  that 
part  where,  proportionally  speaking,  we  find  the  most  of  gray  sub- 
stance. 

In  all  the  rest  of  the  course  of  the  nerve  this  substance  is  particu- 
larly abundant  in  the  inner  side.  On  the  outside  it  is  seen  near  the 
lower  face. 

The  lower  face  of  the  bulb  is  the  only  part  of  the  olfactory  nerve 
whence  filaments  arise.  These  filaments,  each  of  which  is  surrounded 
by  a small  prolongation  of  the  dura-mater,  pass  through  the  openings 
of  the  cribriform  plate  of  the  ethmoid  bone,  thus  enter  in  the  nasal 
fossa,  and  are  mostly  distributed  in  the  mucous  membrane  which  lines 
the  septum  and  the  turbinated  bones.  They  are  distinguished  into 
internal , middle,  and  external.  We  shall  mention  the  manner  in  which 
they  are  distributed  when  describing  the  organ  of  smell.(l) 


CHAPTER  III. 


GANCLIONNARY  NERVE. 

§ 1881.  The  ganglionnary  nerve,  the  nervous  system  of  the  gan- 
glions, the  great  sympathetic  nerve,  the  intercostal , the  trisplanchnir. 
nerve  (N,  gangliosus,  s.  N.  sympatheticus  magnus , s.  intercostalis 
maximus,  s.  vertebralis,  Lieutaud,  s.  trisplanchnicns , s.  sysiema  vitce 
antomaticœ  vegetatives,  Bichat,  Gall),(l)  differs  so  remarkably  from  all 

(1)  The  olfactory  nerve  has  been  considered  as  the  conductor  of  the  sensations 

produced  by  odors.  Magendie,  however,  refers  this  function  to  the  fifth  pair,  which 
sends  so  many  different  twigs  into  the  nose.  He  rests  his  opinion  on  the  fact,  that 
the  destruction  of  the  olfactory  nerves,  and  even  of  the  anterior  cerebral  nerves,  is 
not  attended  with  the  loss  of  smell,  which,  however,  is  always  the  case  when  the 
two  nerves  of  the  fifth  pair  are  divided  (Le  nerf  olfactif  est-il  l’organe  de  l’odorat  ? 
in  the  Journ.  de  phys.  expérim.,  vol.  iv.  p.  69).  If  this  opinion  be  confirmed,  the 
ethmoid  nerve  does  not  differ  in  this  respect  from  the  hypoglossal.  P.  T. 

(2)  Consult.  1st.  On  this  nerve  in  general  : C.  Bergen,  De  nerro  intercostali, 
Erfort,  1731. — A.  F.  Walter,  Programma  quo  paris  intercostalis  et  ragi  corporis 
humani  nervorum  et  ab  ulroque  latere  ejus  obviorum  analomen  exhibet,  Leipsic,  1733, 
1735. — J.  F.  Huber,  De  nerro  intercostali , de  nervo  octavi  et  noni  paris  deque  acces- 
sorio,  Cassel,  1744. — C.  C.  Schmidel,  De  nervo  intercostali,  Erlangen,  1754. — M. 
Girardi,  De  nerro  intercostali,  Florence,  1791. — A.  Portal,  Description  du  nerf  inter- 
costal dans  l’homme;  in  the  Mém.  de  l’Institut,  vol.  iv.  Paris,  au.  xi.  p.  151,  209, 


81 


EF.SCKIPTIVE  ANATOMY. 


the  other  nerves  and  is  so  opposed  to  the  rest  of  the  nervous  system  in 
several  respects  that  it  would  be  more  proper  not  to  place  it  in  the 
same  class  with  the  encephalon,  the  spinal  marrow  and  their  nerves, 
but  to  consider  it  as  a different  but  subordinate  system. 

§ 1882.  This  system  is  formed  of  numerous  ganglions,  varying  in 
number  and  size  not  only  in  both  sides  of  the  same  subject  but  also  in 
different  individuals,  and  of  nervous  twigs,  some  of  which  unite  these 
ganglions  in  several  different  ways,  while  others  are  given  off  to  enter 
the  organs.  It  exists  uninterruptedly  on  the  two  sides  and  the  ante- 
rior face  of  the  vertebral  column,  along  the  neck,  chest,  and  abdomen, 
so  that  its  two  halves  frequently  anastomose  on  the  median  line 
it  extends  from  the  base  of  the  skull  to  the  lower  extremity  of  the 
trunk,  and  is  distributed  in  the  organs  of  vegetative  life. 

The  ganglions  of  this  nervous  system  divide  in  respect  to  their  situa- 
tion and  mode  of  distribution  into  two  classes  which  comprise,  the  first 
the  internal  or  central  ganglions , the  second  the  limiting  ganglions. 

The  central  ganglions  are  principally  situated  in  the  abdomen,  around 
and  above  the  trunks  of  the  large  vessels  near  the  principal  organs, 
those  which  appear  most  independent  in  their  functions.  Several  adja- 
cent ganglions  are  united  to  each  other  by  larger  or  shorter  filaments, 
and  thus  form  a plexus  whence  arise  some  nerves  which  go 
to  the  organs,  also  some  filaments  which  anastomose  with  other 
similar  plexuses.  The  limiting  ganglions  are  situated  on  the  two 
sides  of  the  vertebral  column  in  succession.  They  are  fewer  in  the 
neck  than  in  the  chest  and  abdomen,  and  are  generally  found  in  the 
two  latter  sections  of  the  trunk  between  each  two  vertebrae.  They 
are  situated  behind  the  serous  membranes  of  the  thoracic  and  abdomi- 
nal cavities,  and  anastomose  by  some  longitudinal  cords  with  each 
other  and  with  the  central  ganglions  by  some  oblong  or  transverse 
fibres,  and  with  most  of  the  nerves  of  the  centre  of  the  nervous  system 


in  the  Anat.  med.,  vol.  iv. — Bock,  Ueber  das  Gangliensystem  ; in  Abhandlung  über 
das  fünfte  Nervenpaar , Meissen,  1817. — E.  H.  Weber,  Anatomia  comparata  nervi 
sympathetici,  Leipsic,  1817. — J.  F.  Lobstein,  De  nervi  sympathetici  liumani  fabrica, 
usu  et  morbis,  Paris,  1823. — 2d.  On  its  origin  : D.  Iwanhoff,  De  origine  nervorum, 
intercostal  ium,  Strasburg,  1780.- — J.  Munniks,  Observatio  qua  'ad  illustrandam 
artem  medicam,  ostenüitur  origo  nervi  intercostalis , ejusque  commercium  cum  aliis 
nervis,  ab  ejus  origine  usque  ad  exitum  e calvaria , cum  autopsia , tum  observatis 
medicis  confirmata;  in  his  Observ.  var.,  Groningen,  1805,  no.  ii. — 3d.  On  some  of  its 
parts  : C.  T.  1 .udwig,  De  ple.vibus  nervorum  abdominalium  atque  nervo  intercostali 
duplici  observationes  nonnullœ,  Leipsic,  1772. — H.  A.  Wrisberg,  Obs.  anat.  de  nervis 
viscerum  abdominalium  partie.  I ; de  ganglio  plexuque  semilunari , Gottingen,  1780. 
G.  Walter,  Tabulae  nervorum  thoracis  et  abdominis , Berlin,  1783. — H.  A.  Wrisberg, 
De  nervis  vise,  abdom.,  part  ii.,  de  nervis  systematis  cœliaci.  Sectio  1 ; de  nervis  gas- 
tricis,  quee  est  observationum  de  ganglio  plexuque  semilunari  continuatio  ; in  the 
Syllogc  comment.,  1800,  p.  551,  570. — H.  A.  Wrisberg,  Obs.  anat.  neurolog.  de  nervis 
viscer.  abdom.,  part  iii.,  de  nervis  systematis  cœliaci  II ; de  nervis  hepaticis  et  sple- 
nicis,  quœ  est  observationum  de  ganglio  plexuque  semilunari  continuatio  II,  Got- 
tingen, 1808. — 4th.  On  its  functions.  Broussais,  Réflexions  sur  les  fonctions  du  sys- 
tème nerveux  en  general,  sur  celles  du  grand  sympathique  en  particulier,  et  sur 
quelques  autres  points  de  physiologie  ; in  the  Journ.  unir,  des  $c.  mêd.,  vol.  xii. 


OF  THE  NERVOUS  SYSTEM. 


85 


particularly  with  the  anterior  and  posterior  branches  of  all  the  spinal 
nerves  by  intermediate  filaments. 

Such  is  the  most  general  view  of  the  ganglionnary  nerve  which  can 
be  presented.  The  chain  of  the  limiting  ganglions  and  of  the  nervous 
cords  which  unite  them  have  been  generally  and  until  lately  consi- 
dered as  its  trunk  and  its  upper  extremity  as  its  origin,  admitting  that 
prolongations  proceed  outward  from  these  two  points  to  the  nervous 
system  of  animal  life,  inward  to  the  thoracic  and  abdominal  viscera. 
But  now  it  is  admitted  to  be  more  proper  to  describe  first  its  most 
internal  part,  and  to  conclude  with  the  history  of  the  ganglions 
which  connect  it  with  the  nervous  system  of  animal  life,  and  the  fila- 
ments which  establish  this  communication. 

I.  CENTRAL  PORTION. 

§ 1883.  The  centre  of  the  ganglionnary  nerve  is  formed  of  several 
ganglionnary  plexuses  situated  in  the  cavity  of  the  abdomen,  and  of 
the  nerves  which  proceed  from  them  to  the  organs,  and  the  limiting 
ganglions.  These  plexuses  considered  from  above  downward  are  as 
follow  : 

§ 1884.  The  solar  plexus,  the  semilunar  ganglion , the  suprarenal 
ganglion  and  median  plexus  ( P . Solaris , Willis,  s.  G.,  s.  P.  semi-lu- 
naris,  abdominalis,  transversus,  communis,  cerebrum  abdominale ) de- 
serves to  be  first  studied,  since  from  its  size,  the  constancy  of  its  gan- 
glions whence  all  the  abdominal  plexuses  emanate,  and  its  direct 
connection  with  several  of  the  limiting  ganglions,  it  is  the  real  centre 
of  the  nerve. 

It  is  situated  before  the  abdominal  aorta  behind  the  peritoneum  be- 
tween the  two  renal  capsules,  and  it  surrounds  the  trunk  of  the  cceliac 
artery. 

The  ganglions  which  unite  to  form  it  vary  in  number  and  size. 
We  however  always  find  at  least  two  ganglions,  a right  and  a left, 
which  when  many  exist  are  always  the  largest.  They  are  almost 
semicircular,  generally  more  than  an  inch  long,  about  half  an  inch 
broad  in  several  parts  particularly  in  the  centre,  and  several  lines  thick 
from  before  backward.  Their  convex  edge  is  turned  outward,  their 
concave  edge  inward. 

The  right  is  generally  much  larger  than  the  left,  broader  in  propor- 
tion to  its  length,  angular  and  rhomboidal.  It  is  situated  between 
the  ascending  vena-cava  and  the  right  pillar  of  the  diaphhragm,  and 
the  right  renal  artery  and  the  upper  extremity  of  the  right  renal  cap- 
sule. 

The  left.,  smaller,  is  proportionally  larger  and  more  semicircular  ; it 
is  situated  between  the  left  pillar  of  the  diaphragm,  the  pancreas,  the 
splenic  artery,  and  the  left  renal  capsule. 

Both  are  united  by  numerous  nervous  filaments  which  proceed  trans- 
versely from  the  internal  edge  and  the  two  extremities  of  one  to  the 

Vol.  III.  “ 12 


86 


DESCRIPTIVE  ANATOMY 


corresponding  points  of  the  other.  All  or  most  of  these  filaments  ra- 
mify more  or  less  in  their  course  and  frequently  anastomose. 

We  usually  observe  between  the  two  principal  ganglions,  particu- 
larly between  their  lower  extremities  in  the  space  between  the  cœliac 
and  superior  mesenteric  arteries,  two  or  three  which  are  smaller  : these 
anastomose  with  each  other  and  with  the  two  larger  ones  by  interme- 
diate filaments,  and  apparently  belong  sometimes  to  the  right  and 
sometimes  to  the  left  ganglion. 

Sometimes  the  principal  ganglions  instead  of  being  thicker  and 
broader  at  their  centre  as  is  usual,  are  very  narrow  there,  while  they 
enlarge  at  their  extremities.  This  arrangement  is  the  first  step  to- 
wards a rare  anomaly,  where  they  divide  from  above  downward  in  a 
variable  number  of  enlargements  which  communicate  by  nervous  fila- 
ments. The  middle  enlargements  thus  formed  are  generally  the 
largest  ; but  sometimes  although  more  rarely  they  are  smaller  than 
the  superior  and  inferior,  which  renders  the  arrangement  of  the  nerve 
still  more  abnormal. 

The  ganglions  in  the  first  case  are  nearer  each  other  than  in  this 
latter  ; in  the  latter  case  they  are  sometimes  united  in  several  nervous 
filaments  interwoven  like  a plexus.  Sometimes  from  three  to  eleven 
small  subordinate  ganglions  form  on  the  outside  above  and  below  one 
or  both  of  the  principal  ganglions  ; from  these  arise  filaments  which 
go  to  the  adjacent  plexuses,  and  also  those  which  assist  to  form  the 
great  splanchnic  nerve.  The  principal  ganglion  of  the  same  side  is 
more  or  less  enlarged,  so  that  this  formation  leads  still  more  directly 
to  that  where  it  is  entirely  divided  into  a considerable  number  of 
smaller  ganglions  which  are  nearly  equal  in  size. 

Of  all  these  forms  those  where  the  central  portion  is  most  concen- 
trated is  evidently  superior  to  the  others  : they  present  a very  remark- 
able repetition  of  the  development  of  the  centre  of  the  nervous  system 
of  animal  life  both  in  the  fetus  and  in  the  whole  series  of  animals. 

The  whole  solar  plexus  is  considerably  large  and  extends  longitu- 
dinally from  the  upper  edge  of  the  cceliac  artery  to  below  the  renal 
arteries,  and  it  is  from  one  to  two  inches  broad. 

It  generally  divides  like  the  cœliac  artery  into  three  principal  parts. 

Some  nervous  filaments  proceed  directly  from  its  middle  and  upper 
part  ; they  unite  to  other  filaments  of  the  left  pneumo-gastric  nerve, 
give  rise  to  the  superior  coronary  plexus  of  the  stomach,  stomo-gas- 
trique , Ch.  (P.  coronarius , s.  ventriculi  superior , s.  minor),  which 
accompanies  the  superior  coronary  artery  along  the  small  curve  of  the 
stomach,  extends  to  the  left  orifice  of  this  viscus  and  anastomoses  par- 
ticularly on  the  posterior  face  of  the  stomach  with  the  inferior  coronary 
and  the  left  hepatic  plexus,  with  which  it  communicates  by  twigs. 

The  second  and  largest  of  these  plexuses  is  termed  the  hepatic 
plexus  (P.  hepaticus).  It  descends  from  left  to  right.  One  portion, 
attends  the  right  inferior  coronary  artery  along  the  great  curve  of  the 
stomach,  where  it  is  distributed  and  is  termed  the  inferior  coronary 
plexus  ( P.  coronarius  stomachicus  inferior)  ; the  other  is  larger  and. 


OF  THE  NERVOUS  SYSTEM, 


S7 


joins  the  hepatic  vessels  with  which  it  goes  to  the  liver.  It  first  at- 
tends the  hepatic  artery,  but  near  the  sinus  of  the  vena- porta  it  divides 
into  a right  and  a left  hepatic  plexus.  The  first  is  larger  than  the 
other,  and  is  formed  of  from  six  to  eight  filaments.  It  enters  into  the 
right  lobe  of  the  liver  and  the  left  goes  to  its  left  lobe.  Both  anasto- 
mose with  some  filaments  of  the  right  pneumo-gastric  nerve  and  also 
form  at  intervals  small  prominences  in  the  substance  of  the  liver.  Be- 
fore entering  this  gland  they  send  some  filaments  to  the  pylorus,  and 
also  to  theduodenal  and  pancreatic  arteries. 

Independent  of  these  plexuses  a smaller  one  is  sometimes  detached 
from  the  right  semilunar  ganglion,  the  filaments  of  which  proceed 
from  behind  forward  and  from  below  upward  in  the  small  lobe  of  the 
liver. 

The  splenic  plexus  (P.  splenicus ) arises  from  the  right  lower  part  of 
the  solar  plexus  and  the  left  semilunar  ganglion,  the  branches  of  which 
accompanying  those  of  the  splenic  artery  which  they  surround  pass 
on  the  pancreas,  send  some  filaments  to  this  gland,  and  also  to  the 
large  cul-de-sac  of  the  stomach,  where  they  form  the  small  inferior 
plexus  of  the  stomach  ( P . ventriculi  inferior  et  minor),  and  then  enter 
into  the  substance  of  the  spleen  with  the  branches  of  the  splenic  ar- 
tery. 

Some  branches  arise  from  the  lower  part  of  the  semilunar  ganglions 
of  the  solar,  the  hepatic  and  splenic  plexuses,  and  unite  to  form  the  su- 
perior mesenteric  plexus  (P.  mesentericus  superior ).  This  plexus  ac- 
companies the  trunk  and  branches  of  the  superior  mesenteric  artery  : 
its  filaments  are  distributed  principally  to  the  small  and  large  intestine, 
and  some  enter  the  pancreas. 

The  upper  part  of  the  semilunar  ganglions  sends  off  on  each  side 
four  or  five  considerable  branches  which  are  enlarged  by  some  filaments 
from  the  superior  mesenteric  plexus,  descend  towards  the  renal  arte- 
ries, and  interlacing  by  five  or  six  subordinate  ganglions  form  the  renal 
plexus  (P.  renalis ) on  each  side,  which  give  numerous  ramifications  to 
the  renal  capsules  and  to  the  kidneys. 

This  plexus  communicates  upward  and  outward  with  the  inferior 
thoracic  and  the  superior  lumbar  ganglions  by  twigs,  of  which  the 
upper  unite  in  larger  branches  which  go  separately  to  the  limiting 
ganglions  and  the  nervous  cords  by  which  these  latter  are  united. 

The  same  plexus  is  continuous  below  with  the  spermatic  plexus  (P. 
spermaticus),  which  descends  along  the  spermatic  vessels,  anastomoses 
with  the  superior  and  inferior  mesenteric  plexuses,  gives  some  fila- 
ments to  the  ureter,  and  extends  in  man  to  the  testicle,  in  the  female 
to  the  ovary. 

Some  branches  arise  below  from  the  superior  mesenteric  plexus, 
descend  before  the  abdominal  aorta,  and  enter  the  inferior  mesenteric, 
the  left  colic  plexus  (P.  mesentericus,  s.  mesaraicus  inferior , s.  médius, 
Vieussens) . This  latter,  which  is  smaller  than  the  upper,  embraces 
the  inferior  mesenteric  artery.  It  contains  but  a few  small  ganglions 
near  this  artery. 


88 


DESCRIPTIVE  ANATOMY. 


On  entering  the  pelvis  it  divides  into  two  pairs,  one  the  'proper  infer- 
rior  mesenteric  plexus  attends  the  branches  and  twigs  of  the  inferior 
mesenteric  artery,  and  anastomoses  with  the  lumbar  ganglion  and 
sometimes  also  with  the  anterior  branches  of  some  lumbar  nerves. 

The  other  has  a direction  outward  and  downward,  is  termed  the 
hypogastric  plexus  (P.  hypogastricus,  s.  mesentericus  inferior,  s.  ter- 
tins,  s.  posterior ),  anastomoses  with  the  lumbar  and  sacral  portions  of 
the  terminal  cord  of  the  ganglionnary  nerve  like  the  sacral  nerves,  and 
attending  the  hypogastric  vessels  is  distributed  to  the  rectum  and  the 
bladder,  and  in  the  male  to  the  prostate  gland  and  vesiculæ  séminales, 
in  the  female  to  the  uterus  and  vagina.  It  also  emerges  from  the 
pelvis  with  the  external  branches  of  the  hypogastric  artery. 

II.  LIMITING  CORD  AND  ITS  BRANCHES. 

§ 1885.  We  have  already  mentioned  generally  the  arrangement  of 
the  limiting  cord  which  is  situated  on  the  two  sides  of  the  vertebral 
column  and  the  skull.  We  describe  it  from  above  downward,  and 
.commence  by  the  superior  cervical  ganglion  which  exists  constantly. 

A.  SUPERIOR  CERVICAL  GANGLION. 

§ 1886.  The  superior  cervical,  the  olivary  or  fusiform  ganglion  (Gr 
cemicale  supreinum,  s.  olivare,  s.  fusiforme),  one  of  the  largest  of  those 
of  the  ganglionnary  nerve,  is  situated  above  and  behind  the  angle  of 
the  lower  jaw,  behind  the  internal  carotid  artery  before  the  transverse 
processes  of  the  second  and  third  cervical  vertebræ  and  the  rectus  ca- 
pitis major  anticus  muscle,  on  the  inside  of  the  pneumo-gastric  and 
hypoglossal  nerves.  It  is  surrounded  by  a cellular  sheath  which  em 
velops  also  the  trunk  of  the  pneumo-gastric  nerve. 

Its  form  and  size  vary  much.  It  is  almost  always  oblong,  thinner 
below  than  above,  terminates  however  also  in  a point  at  its  upper  and 
fusiform  extremity.  Sometimes  it  tends  to  divide  into  several  gan- 
glions situated  successively  from  above  downward.  The  first  degree 
of  this  anomaly  is  a contraction  in  its  centre.  Next  comes  the 
formation  of  an  upper  or  lower  appendage  ; we  then  observe  contrac- 
tions in  two  or  three  points.(l)  It  does  not  constantly  extend  en- 
tirely to  the  carotid  canal.  Below  it  usually  descends  to  the  third, 
sometimes  however  to  the  sixth  cervical  vertebra.  Generally  it  is  an 
inch  and  a half  long  and  its  greatest  breadth  is  three  lines  ; its  length 
however  varies  from  some  lines  to  four  inches,  but  its  breadth  and 
thickness  are  always  inversely  as  its  length. 

It  sends  off  numerous  branches  upward,  outward,  inward,  forward, 
and  downward. 

(1)  Lobstein  ha3  figured  (tab.  v.  fig.  3)  a superior  cervical  ganglion  which  he  has 
found  double. 


OP  THE  NERVOUS  SYSTEM. 


89 


I.  UPPER  BRANCHES. 

1 . The  superior  branch  is  sometimes  although  very  rarely  double, 
leaves  the  upper  extremity  of  the  ganglion,  enters  into  the  carotid 
canal,  and  establishes  a communication  between  the  ganglionnary 
nerve  and  the  portion  of  the  nervous  system  of  animal  life  contained  in 
the  skull.  It  is  situated  behind  the  internal  carotid  artery  towards  the 
lower  curve  of  which  it  usually  divides  into  two  nearly  equal  branches 
which  separate  at  an  acute  angle  and  ascend  in  the  canal  before  the 
carotid  artery,  one  being  more  external  than  the  other. 

Opinions  vary  both  in  regard  to  their  mode  of  anastomosis  and  the 
number  of  the  portions  of  the  nervous  system  contained  within  the 
skull,  with  which  the  ganglionnary  nerve  communicates  by  these 
filaments  ; these  differences  in  opinion  depend  partly  on  the  difficulty 
of  dissecting  such  delicate  parts,  partly  on  the  varieties  in  their  ar- 
rangement. 

The  most  ancient  opinion  was  that  the  ganglionnary  nerve  anasto- 
mosed only  with  the  fifth  pair.(l) 

At  a later  period  it  was  asserted  to  anastomose  only  with  the  ex- 
ternal motor  nerve. (2) 

"Then  it  was  admitted  to  be  connected  with  both. (3) 

Anatomists  vary  also  as  to  the  point  where  the  ganglionnary  nerve 
-communicates  with  the  two  encephalic  nerves  ; the  differences  in 
opinions  are  but  slight  and  trivial  in  regard  to  the  external  motor  nerve  ; 
but  they  are  great  in  regard  to  the  fifth  pair,  for  it  anastomoses  ac- 
cording to  some  with  the  trunk  of  this  nerve, (4)  according  to  others 
with  one(5)  or  more(6)  or  even  with  all  of  its  branches.  Some  think 
■they  communicate  directly, (7)  others  indirectly  and  by  ganglions  :(8) 
the  descriptions  also  of  the  anastomosis  with  the  sixth  pair  vary  in  this 
last  respect. 

§ 1887.  The  ganglionnary  nerve  always  anastomoses  with  the  sixth 
pair  in  the  carotid  canal  by  a considerable  branch  coming  from  the 
superior  cervical  ganglion,  which  ascends  along  the  internal  carotid 
artery  first  on  the  outside  and  then  on  its  anterior  face. 


(4)  Galen,  De  nervorum  origine  ; in  Op.  omn.,  Venice,  Vot.  ii.  p.  54. — The  Ara- 
bians and  the  first  Italian  anatomists  have  adopted  his  opinion.  Rau  and  Valsalva 
assert  that  they  have  sometimes  observed  this  arrang-ement  since.  (Morgagni, 
Ep.  an.  xvi.  p.  330.) 

(2)  Eustachius,  tab.  xviii.  fig.  2. — Morgagni,  Adv.  anal .,  vol.  vi.p.  30. — Santorini. 
Obs.  anat.,  c.  iii.,  p.  67. 

(3)  Meckel. 

(4)  Schmidel,  Munniks,  Bock. 

(5)  Most  authors. 

(6)  Laumonier. 

(7)  Most  authors  who  have  written  on  this  subject,  and  on  neurology  in  general. 
(3)  Petit,  loc.  cit. — Schmidel,  loe.  cit. — Laumonier,  in  Bacher,  Journ.  de  méd.,  vol. 

xciii.,  March,  1793,  p.  259. — Munniks,  Obs.  nor.— Cloquet,  TV.  d’anat.,  vol.  ii.,  p. 


90 


DESCRIPTIVE  ANATOMY. 


This  branch  generally  unites  to  the  external  motor  nerve  by  a single 
twig  which  meets  it  and  is  detached  at  an  acute  angle  from  the  ex- 
ternal and  inferior  part  of  the  sixth  pair  during  its  passage  through  the 
cavernous  sinus. 

This  twig  is  not  unfrequently  double  and  sometimes  the  recurrent 
filament  of  the  external  motor  nerve  bifurcates  soon  after  arising. 

Sometimes  also  the  anastomosing  branch  of  the  ganglionnary  nerve 
within  the  sixth  pair  is  double,  in  which  case  one  proceeds  on  the  out- 
side the  other  on  the  inside  of  the  internal  carotid  artery. 

We  frequently  and  even  perhaps  always  find  at  the  upper  part  of  the 
carotid  canal  or  in  the  cavernous  sinus,  instead  of  a direct  anastomosis, 
a ganglion  situated  on  the  outside  of  the  internal  carotid  artery  called 
the  cavernous  ganglion  (G.  caver  no  sum).  Three  or  more  filaments 
proceed  from  the  summit  of  this  ganglion  to  the  nerve  of  the  sixth 
pair . ( 1 ) 

The  anastomosis  with  the  trifacial  nerve  is  always  by  a filament 
which  goes  to  the  recurrent  twig  of  the  second  branch  of  the  fifth  pair 
or  the  vidian  nerve.  This  filament  is  distributed  partly  in  the  carotid 
artery,  partly  also  emerges  from  the  carotid  canal,  passes  through  the 
dura-mater  and  enters  the  pterygoid  canal  where  it  unites  with  the 
recurrent  twig. 

Thus  the  branch  from  the  upper  extremity  of  the  upper  cervical 
ganglion  usually  divides  into  these  two  filaments,  one  of  which  goes 
to  the  external  motor,  the  other  to  the  trifacial  nerve. 

This  bifurcation  generally  takes  place  within  the  carotid  canal,  sel- 
dom below  and  never  above  it. 

Sometimes  but  rarely  also  the  upper  extremity  of  the  superior  cer- 
vical ganglion  gives  origin  to  two  superior  branches,  which  go  one  to 
the  external  motor  the  other  to  the  vidian  nerve. 

When  this  arrangement  exists  the  two  anastomotic  filaments  and 
the  vidian  nerve  communicate  with  the  external  motor  nerve.  Some- 
times also  this  triple  anastomosis  does  not  exist. 

An  analogous  case  is  where  either  the  anastomosing  filament  which 
goes  to  the  external  motor  nerve  or  that  which  proceeds  to  the  trifacial 
or  both  divide  into  several  filaments,  all  of  which  unite  in  a common 
trunk  to  go  to  the  superior  cervical  ganglion. 

§ 1888.  This  is  the  only  anastomosis  admitted  by  most  authors 
between  the  ganglionnary  and  the  trifacial  nerves.  In  fact  it  is  often 
the  only  one  which  can  be  demonstrated.  But  the  great  sympathetic 
nerve  also  unites  by  its  upper  extremity  in  another  manner,  at  least 
sometimes,  with  the  trifacial  nerve. 

Many  anatomists,  and  Portal  among  others,  positively  reject  this 
other  anastomosis  ; but  many  observations  favor  its  existence. 

In  fact  according  to  Schmidel  and  Munniks,  several  filaments  come 
from  the  ganglionnary  plexus  of  the  fifth  pair  and  go  to  the  carotid 


(1)  Laumonier,  loc.  cit. — Munniks,  loc.  cit. 


OF  THE  NERVOUS  SYSTEM. 


91 


canal,  where  they  unite  with  other  filaments  of  the  external  motor 
nerve  and  form  a ganglion. 

Others  however  whose  opinions  are  like  the  preceding,  assert  that 
beside  those  filaments  mentioned,  or  even  if  they  do  not  exist,  we  find 
a smaller  twig  coming  from  the  first  branch  of  the  fifth  pair  ; and  this 
unites  sooner  or  later  either  with  the  anastomosing  filament  of  the 
sixth  pair,  as  Petit, (1)  Schmidel,(2)  and  Coopmanns(3)  assert,  or  with 
the  cavernous  ganglion. (4) 

Laumonier,  on  the  contrary,  has  found  coming  from  the  cavernous 
ganglion,  the  two  filaments  which  anastomose  with  the  sixth  pair  and 
the  vidian  nerve,  and  also  a third  which  went  to  the  second  branch  of 
the  fifth  pair,  and  a fourth  to  the  fourth  branch  of  this  same  pair.(5) 
Bock(6)  asserts  that  ten  filaments  go  to  the  anterior  extremity  of  the 
trunk  of  the  fifth  pair,  particularly  towards  the  portion  which  corres- 
ponds to  the  first  branch. 

All  these  assertions,  however  agree,  in  this,  that  besides  the  fila- 
ment which  anastomoses  with  the  vidian  nerve,  one  or  more  anasto- 
moses exist  nearer  the  origin  of  the  fifth  pair  with  one  or  several  of  its 
three  principal  branches,  or  with  its  trunk  : these  anastomoses  take 
place  by  a ganglion,  and  from  this  arises  the  filament  of  communica- 
tion with  the  superior  cervical  ganglion. (7) 

We  also  sometimes  find  a more  indirect  anastomosis  between  the 
upper  extremity  of  the  ganglionnary  nerve  and  the  third  pair  of  cere- 
bral nerves,  the  latter  anastomosing  with  the  sixth  and  fifth  in  the 
place  where  they  give  filaments,  which  communicate  with  the  great 
sympathetic  nerve. (8) 

According  to  Fontana(9)  and  Ribes,(10)  whose  correctness  we  have 
partially  attested,  the  ganglionnary  nerve  penetrates  still  farther  up- 
ward and  forward,  for  it  sends  some  filaments  from  the  carotid  canal  to 
the  pituitary  gland,(ll)  or  to  theinfundibulum,(12)  and  also  a fasciculus 
which  accompanies  the  ophthalmic  artery,  forms  a plexus  around  the 
different  branches  of  this  vessel,  not  excepting  the  central  artery  of  the 
retina,  and  anastomoses  by  a filament  with  the  lenticular  ganglion, 

(1)  Loc.  cit.,  p.  4. 

(2)  Loc.  cit.,  p.  16,  21. 

(3)  Loc.  cit.,  p.  219. 

(4)  Cloquet,  loc.  cit.,  p.  687. 

(5)  Loc.  cit.,  p.  259. 

(6)  Vom fiinften  Nerven,  p.  3. 

(7)  Lobstein  does  not  admit  all  these  anastomoses  ; he  has  seen  some  transparent 

and  gelatinous  filaments  which  united  the  ramifications  of  the  great  sympathetic 
nerve  with  the  common  motor  and  other  nerves;  but  by  examining  them  with  the 
microscope,  he  has  not  found  in  them  the  characters  of  nervous  organs.  He  regards 
them  as  cellular  tissue  extended  in  filaments.  F.  T. 

(8)  Munniks,  loc.  cit.,  p.  25. 

(9)  In  Girardi,  loc.  cit.,  p.  25.  As  Carus  ( Anatomie  und  Physiologie  des  Nerven- 
systems, p.  185)  has  also  observed  in  several  reptiles. 

(10)  Ribes,  Rech.  anat.  etphys.  sur  quelques  parties  de  l'œil  ; in  the  Mém.  de  la  sec. 
mêd.  d'émul.,  vol.  vii.  p.  97. 

(11)  Fontana,  loc.  cit.,  p.  56,  57. 

(12)  Cloquet,  loc.  cit. 


92 


DESCRIPTIVE  ANATOMY. 


consequently  with  the  first  principal  branch  of  the  fifth,  and  with  the 
third  pair.(l).  And  likewise  as  there  exists  also  between  the  lenti- 
cular ganglion,  the  cavernous  sinus,  and  all  the  ganglionnary  system, 
a constant  relation, (2)  similar  to  that  between  the  two  ganglions,  we 
consider  this  small  filament  with  the  ciliary  nerves  which  come  from  it, 
as  making  part  of  the  great  sympathetic  nerve,  which  supposition 
seems  to  us  very  probable. 


II.  EXTERNAL  BRANCHES. 

The  external  branches  are  from  one  to  four  in  number,  pass  above' 
the  rectus  capitis  major  anticus  muscle,  to  go  and  meet  the  first  and 
second  cervical  nerve.  When  there  is  only  one,  it  is  larger,  and  soon 
divides  into  as  many  branches  as  generally  exist,  comes  sometimes 
from  the  upper,  and  sometimes  from  the  centre  of  the  superior  cervical 
ganglion.  The  upper  two  arise  from  the  upper  extremity  of  this  same 
ganglion,  directly  at  the  side  of  each  other,  and  anastomose  with  the 
anastomotic  plexus  of  the  first  and  second  cervical  nerves.  The  third 
communicates  with  that  of  the  third  and  fourth  cervical  pairs.  The 
fourth  which  arises  more  frequently  from  the  twig  of  communication 
between  the  first  and  second  cervical  ganglions,  anastomoses  on  one 
side  by  several  filaments  with  the  anastomotic  plexus  of  the  third  and 
fourth  cervical  nerves,  and  is  distributed  in  the  rectus  capitis  major 
anticus  and  the  scalenus  anticus  muscle. 

III.  INTERNAL  BRANCHES. 

The  internal  branches  are  much  smaller  and  less  constant  in  respect 
to  number,  and  are  distributed  to  the  longus  colli,  the  rectus  capitis 
major  anticus  muscle,  the  pharynx  and  the  larynx. 

IV.  ANTERIOR  BRANCHES. 

The  anterior  branches  are  the  largest  and  most  numerous.  They 
are  distinguished  by  their  reddish  tint  and  their  softness,  and  hence 
are  termed  soft  nerves  ( N . molles ).  The  superior  are  shorter  than  the 
others,  proceed  from  below  upward,  and  anastomose  with  the  hypo- 
glossal, the  pneumo- gastric,  and  the  facial  nerves,  just  after  they 
emerge  from  the  skull.  The  middle  and  inferior  are  larger,  go  forward' 
and  downward,  envelop  the  primitive  carotid  arteries  to  their  origin, 
anastomose  in  this  course  with  some  branches  of  the  pneumo-gastric 
nerve,  and  surround  also,  together  with  the  facial  and  pneumo-gastrie 
nerves,  the  branches  of  the  external  and  internal  carotid  arteries,  to 
the  carotid  canal.  The  latter  not  unfrequently  come  from  a distinct 
small  ganglion. 


(1)  Ribcs.— Cloquet.— Bock. 

(2)  Ribes.— Cloquet.— Bock. 


OF  THE  NERVOUS  SYSTEM. 


93 


The  largest  anterior  branch  is  the  superior  or  superficial  cardiac 
nerve  (JV.  cardiacus  superior , s.  superficialis ),  which  arises  by  from 
four  to  six  filaments  from  the  internal  anterior  part  of  the  cervical  gan- 
glion, sometimes  also  partially  or  wholly  from  the  upper  extremity 
of  the  cord  which  joins  this  ganglion  to  the  following.  The  minute 
nerve  formed  by  the  union  of  these  filaments,  descends  on  the  outside 
of  the  primitive  carotid  artery,  covered  by  the  cord  of  communication 
of  the  great  sympathetic  nerve,  gives  off  at  about  its  centre  some  fila- 
ments which  surround  the  inferior  thyroid  artery,  anastomoses  with 
one  or  two  twigs  of  the  pneumo-gastric  nerve,  communicates  also  with 
the  descending  branch  of  the  hypoglossal  nerve,  gives  ramifications  to 
the  pharynx,  the  esophagus,  the  sterno-hyoideus  and  sterno-thyroideus 
muscles,  and  usually  terminates  partly  by  anastomosing  with  some 
ramuscules  of  the  recurrent  branch  of  the  pneumo-gastric  nerve,  and 
partly  sends  retrograde  filaments  to  the  thyroid  gland.  It  more  rarely 
descends  to  the  arch  of  the  aorta,  where  it  unites  to  the  middle  car- 
diac nerve  ; but  it  never  extends  to  the  heart.,  so  that  it  does  not  de- 
serve the  term  applied  to  it. 

That  of  the  left  side  commonly  extends  farther  than  that  of  the 
right. 

V.  INFERIOR  BRANCH. 

The  inferior  branch  establishes  the  communication  between  the  su- 
perior and  the  middle,  or  the  inferior  cervical  ganglion,  and  is  generally 
considered  as  the  continuation  of  the  trunk.  It  varies  in  size  and  firm- 
ness. It  is  generally  thinnest  in  its  centre,  and  is  always  larger  than  the 
superior  cardiac  nerve  which  is  situated  before  and  on  the  inside  of  it. 
It  constantly  arises  from  the  lower  extremity  of  the  superior  cervical 
ganglion,  with  which  it  is  less  directly  continuous,  the  larger  it  is  and 
the  smaller  the  ganglion.  Its  length  depends  on  that  of  the  superior 
ganglion,  and  on  the  presence  or  absence  of  the  middle  one.  It 
always  exists.  It  is  situated  before  the  rectus  capitis  major  anticus 
and  the  longus  colli  muscles,  near  the  inner  edge  of  this  latter,  first  be- 
hind the  internal  carotid  artery,  then  behind  the  primitive  carotid, 
between  the  internal  jugular  vein  and  the  pneumo-gastric  nerve. 

It  is  most  generally  single.  Very  rarely  it  is  divided  at  its  lower 
part  into  two  twigs,  which  embrace  the  inferior  thyroid  artery,  and 
which  usually  enter,  one  the  middle  cervical  ganglion,  the  other  the 
inferior  cervical  ganglion. 

This  branch  anastomoses  by  some  external  filaments  with  the  ac- 
cessory and  several  cervical  nerves,  more  frequently  with  the  superior 
than  the  inferior,  sometimes  even  with  the  eighth.  These  differences 
and  those  in  the  length  of  the  cord,  depend  on  those  in  the  size  of  the 
superior  cervical  ganglion,  and  also  on  the  presence  or  absence  of  the 
middle  ganglion.  The  anastomosing  branches  generally  unite  in 
some  larger  branches  before  coming  to  the  trunk  of  the  ganglionnary 
nerve. 

VOL.  III. 


13 


94 


DESCRIPTIVE  ANATOMY. 


F rom  this  branch  arise  some  filaments  which  contribute  to  form  the 
superficial  cardiac  nerves.  It  gives  some  also  which  unite  to  others 
coming  from  the  superior  cervical  ganglion,  sometimes  arise  only  from 
the  superficial  cardiac  nerves,  and  go  almost  transversely  inward,  and 
are  distributed,  the  superior  particularly,  in  the  constrictor  muscles  of 
the  pharynx,  the  inferior  in  the  thyroid  gland,  the  muscles,  and  the 
mucous  membrane  of  the  larynx.  These  filaments  frequently  anas- 
tomose with  each  other  or  with  some  ramifications  of  the  pneumo- 
gastric  and  glosso-pharyngeal  nerve. 


B.  MIDDLE  CERVICAL  GANGLION. 

1839.  The  middle  cervical  or  thyroid  ganglion  (G.  cervicale  me- 
dium,  s.  thyroideum ) is  situated  at  the  origin  of  the  inferior  thyroid 
artery,  between  the  fifth  and  sixth,  or  between  the  sixth  and  seventh 
cervical  vertebrae,  directly  before  the  longus  colli  muscle,  behind  the 
primitive  carotid  artery  and  the  pneumo-gastric  nerve.  It  is  not  so 
constant  as  the  superior;  it  however  exists  more  frequently  than  it  is 
absent,  and  in  the  proportion  of  3 : 1,  judging  from  our  dissections  ; it  is 
sometimes  extremely  small,  and  sometimes  deficient.  It  is  never  ob- 
long, but  always  broad  and  slightly  flat.  When  deficient,  we  some- 
times, but  not  always,  find  in  its  place  two  inferior  cervical  ganglions, 
in  which  case  consequently,  it  is  only  situated  lower  than  usual. 
Sometimes,  but  much  more  rarely,  it  is  double,  that  is,  it  is  divided  into 
two  small  ganglions,  a superior  and  an  inferior,  the  former  of  which  is 
then  situated  higher  than  the  common  single  ganglion. 

Its  branches  go  upward,  outward,  inward,  forward,  and  down- 
ward. 

The  superior  unites  it  to  the  superior  cervical  ganglion,  which  we 
have  already  described. 

The  external  are  sometimes  reduced  in  number  to  one,  anastomose 
with  one  or  more  of  the  inferior  cervical  pairs,  especially  from  the  fourth 
to  the  sixth. 

The  internal  accompany  the  inferior  thyroid  artery,  on  which  they 
give  rise  to  the  thyroid  plexus  (PI.  thyroideus ),  extend  to  the  thyroid 
gland,  and  go  to  join  and  enlarge  the  recurrent  laryngceal  nerve. 

The  anterior  form  the  middle  or  deep  cardiac  nerve,  the  great  car- 
diac nerve  (N.  cardiacus  médius,  s.  magnus,  s.  profundus ),  which  is 
the  largest.  Five  or  six  filaments  unite  near  the  ganglion,  first  into 
two  or  three  fasciculi,  then  in  a trunk  which  descends  obliquely  from 
without  inward,  first  along  the  primitive  carotid  artery,  then  before  the 
subclavian,  anastomoses  in  its  course  by  several  filaments  with  the 
trunk  of  the  pneumo-gastric  nerve,  and  with  its  recurrent  branch,  and 
unites  with  the  inferior  cardiac  nerve  to  form  the  cardiac  plexus. 

The  middle  cardiac  nerve  differs  on  the  right  and  left  sides. 

That  of  the  right  side,  after  passing  before  the  subclavian  artery, 
descends  along  the  trunk  of  the  innominata,  unites  at  its  bifurcation  by 
a small  ganglion  with  one  or  two  twigs  of  the  pneumo-gastric  nerve, 


OF  THE  NERVOUS  SYSTEM. 


95 


and  then  passes  between  the  arch  of  the  aorta  and  the  bifurcation  of 
the  trachea. 

That  of  the  left  side  arises  by  several  filaments  from  the  middle  cervi- 
cal ganglion,  andfromthe  inferior  ganglion  by  one  or  two  filaments  which 
are  larger  than  the  preceding.  The  two  ganglions  then  unite  in  this 
place,  while  on  the  right  side  they  remain  separate.  The  two  roots 
unite  some  distance  from  the  origin  of  the  subclavian  artery.  The 
trunk  passes  behind  the  arch  of  the  aorta,  there  unites  to  some  fila- 
ments of  the  pneumo-gastric  nerve,  and  anastomoses  with  that  of  the 
right  side,  and  likewise  with  the  two  inferior  cardiac  nerves,  to  form 
the  cardiac  plexus. 

The  inferior  branches  are  very  minute,  shorter  than  the  rest,  and 
five  or  six  in  number.  They  descend  on  the  right  side  before  and 
behind  the  subclavian  artery,  on  the  left  side  before  and  behind  the 
trunk  of  the  aorta,  and  anastomose  with  the  superior  ascending 
branches  of  the  inferior  cervical  ganglion. 

Sometimes  the  anterior  of  these  branches  are  deficient,  and  the  pos- 
terior also  are  united  in  a short  common  trunk,  which  establishes  a 
direct  connection  between  the  two  cervical  ganglions. 

C.  INFERIOR  CERVICAL  GANGLION. 

§ 1890.  The  inferior  cervical  ganglion  (G.  cervicale  inferius)  is 
much  more  constant  than  the  central,  and  is  generally  flat,  rarely 
rounded  and  oblong,  often  very  irregular,  and  sometimes  double.  It 
is  situated  before  the  transverse  process  of  the  seventh  cervical  vertebra 
and  the  neck  of  the  first  rib,  but  sometimes  descends  to  the  second 
rib. 

Its  superior  branches  anastomose  with  the  inferior  of  the  middle 
ganglion.  One  which  is  rather  large,  enters  the  vertebral  canal, 
where  it  entwines  around  the  vertebral  artery,  sends  some  filaments  to 
the  intertransversarii  muscles,  and  terminates  at  the  third  or  second 
cervical  vertebra. 

Sometimes  this  branch  arises  only  from  the  filaments  which  anasto- 
mose with  the  brachial  plexus. 

The  external  are  smaller,  but  numerous,  surround  the  subclavian 
artery,  and  give  ramifications  to  the  muscles  of  the  neck,  and  anas- 
tomose with  the  two  or  three  inferior  cervical  nerves,  and  also  with 
the  first  dorsal,  sometimes  even  but  more  rarely  with  the  second  tho- 
racic pair,  when  the  inferior  cervical  ganglion  is  much  developed. 

The  internal  terminate  principally  in  the  longus  colli  muscle  and 
the  pulmonary  plexus. 

The  anterior  form  the  inferior  cardiac  nerve  (N.  car diacus  inferior. 
s.  tertius , s.  parvus ),  which  generally  exists  only  on  the  right  side,  while 
on  the  left  it  is  only  indicated  by  the  inferior  root  of  the  great  cardiac 
nerve.  These  branches  frequently  interlace  before  uniting  in  a single 
trunk.  The  latter  descends  first  behind  the  subclavian  artery,  then 
before  the  innominata  and  the  arch  of  the  aorta,  anastomoses  often 


96 


DESCRIPTIVE  ANATOMY. 


with  the  pneumogastric  nerve,  gives  some  filaments  to  the  vessels 
situated  near  its  course,  and  goes  to  the  left  between  the  aorta  and  the 
pulmonary  artery,  and  terminates  in  the  anterior  cardiac  plexus. 

CARDIAC  PLEXUS. 

§ 1891.  The  cardiac  plexus  (PI.  cardiacus ) is  formed  principally  by 
the  middle  cardiac  nerves.  It  is  situated  between  the  arch  of  the 
aoi  ta  and  the  bifurcation  of  the  trachea.  It  extends  from  the  division 
of  the  pulmonary  artery  to  the  origin  of  the  innommata. 

Its  anterior  filaments  go  principally  to  the  anterior  wall  of  the  aorta, 
and  the  posterior  to  the  pulmonary  plexus.  The  inferior  are  more 
numerous,  and  go  almost  exclusively  to  the  heart,  where  they  form 
the  two  coronary  plexuses  (PI.  coronarii ),  in  which  also  terminate 
some  filaments  of  the  inferior,  and  more  generally  of  the  superior 
cardiac  nerve. 

The  posterior  coronary  plexus  is  much  larger  than  the  anterior  ; it 
goes  to  the  base  of  the  heart,  descending  on  the  left  pulmonary  artery. 
It  is  distributed  to  the  lower  and  posterior  part  of  the  left  ventricle, 
along  the  posterior  coronary  artery  and  its  branches. 

The  anterior  follows  the  course  of  the  left  inferior  cardiac  nerve,  in 
its  whole  extent,  passes  between  the  aorta  and  the  pulmonary  artery, 
and  after  anastomosing  at  its  upper  part  with  the  posterior,  attends 
the  anterior  coronary  artery  and  its  ramifications,  on  the  upper  face  of 
the  heart  and  the  right  auricle,  where  it  frequently  anastomoses  with 
the  posterior,  along  the  posterior  edge  of  the  organ.  Some  smaller 
twigs  of  this  plexus  proceed  on  the  left  pulmonary  artery,  and  go  to 
the  pulmonary  plexus  of  the  left  side. 

The  two  plexuses  frequently  anastomose  with  some  branches  of  the 
pneumo-gastric  nerve. 

They  are,  however,  mostly  formed  by  the  ganglionnary  nerve. 

After  leaving  the  lower  part  of  the  neck,  the  ganglions  of  the  great 
sympathetic  nerve  are  more  numerous. 

D.  THORACIC  GANGLIONS. 

§ 1892.  We  find  in  the  chest  between  the  transverse  processes  of 
each  two  vertebrae,  and  on  each  side,  a ganglion  called  the  thoracic 
(Gl.  thoracicum).  These  ganglions  are  generally  slightly  rounded, 
elongated,  triangular,  and  fusiform.  They  are  situated  more  on  the 
outside  than  the  cervical.  The  first  counting  from  above  downward 
(G.  thoracicum  supremum)  is  the  largest  of  all  the  limiting  ganglions 
except  the  superior-  cervical.  Sometimes  it  is  blended  with  the  second  ; 
this,  however,  is  rare,  and  even  when  it  appears,  generally  exists  on 
the  outside.  The  middle  ganglions  are  often  a little  smaller  than  the 
superior  and  the  inferior. 


OF  THE  NERVOUS  SYSTEM. 


97 


All  these  ganglions  are  united  to  each  other  by  one  very  strong 
filament,  rarely  by  two. 

The  superior  is  almost  constantly  attached  to  the  inferior  cervical 
nerve  by  two  filaments,  the  anterior,  of  which  not  unfrequently  divides 
in  turn  into  two  smaller  filaments.  Each  thoracic  ganglion  anastomoses 
on  the  outside  by  two  filaments,  with  its  corresponding  thoracic  nerve. 
Internally,  the  superior  gives  off  branches,  some  of  which  go  to  the 
lower  part  of  the  longus  colli  muscle,  others  to  the  cardiac  plexus, 
several  to  the  pulmonary  plexus,  which,  however,  is  principally  formed 
by  the  pneumo-gastric  nerve  ; finally,  some  .proceed  to  the  aorta. 

I.  SPLANCHNIC  NERVE. 

§ 1893.  From  the  inferior  thoracic  ganglions,  and  from  their  fila- 
ments of  union,  generally  from  the  sixth  or  the  seventh  to  the  eleventh, 
arise  cords,  the  upper  of  which  are  usually  the  largest  ; they  vary  in 
number  from  three  to  seven,  and  are  very  rarely  the  same  on  both 
sides  of  the  body  ; they  unite  at  an  acute  angle  near  the  diaphragm, 
to  form  the  splanchnic  nerve,  grand  surrénal , Ch.  (JV*.  splanchnicus). 
This  nerve  descends  behind  the  pleura,  and  generally  goes  from  the 
chest  into  the  abdomen,  between  the  inner  and  middle  prolongations 
of  the  pillar  of  the  diaphragm,  sometimes  also  through  the  aortic  open- 
ing. It  anastomoses  in  the  abdomen  principally  with  the  semilunar 
ganglion  of  its  side,  sometimes  directly,  sometimes  indirectly,  by  some 
small  ganglions.  It  then  forms  the  principle  mode  of  union  between 
the  central  portion  of  the  ganglionnary  nerve  and  the  limiting  gan- 
glions. Not  unfrequently  some  of  the  roots  by  which  it  arises,  parti- 
cularly the  inferior,  go  separately  to  the  semilunar  ganglion,  and  some 
of  them  often  anastomose,  not  with  this  ganglion,  but  with  some  fila- 
ments of  the  solar,  the  hepatic,  the  splenic,  and  the  two  renal  plexuses, 


II.  SMALL  SPLANCHNIC  NERVE. 

§ 1894.  Two  or  three  inferior  branches,  which,  however,  remain 
distinct,  sometimes  unite  on  the  right  side  more  frequently  than  on  the 
left,  in  a small  special  trunk,  called  the  small  splanchnic  nerve,  petit 
surrénal , Ch.  (N.  splanchnicus  minor.)  This  trunk  passes  through 
the  pillar  of  the  diaphragm  below  the  preceding.  It  is  enlarged  by 
some  filaments  from  the  superior  lumbar  ganglions,  and  goes  princi- 
pally into  the  renal  plexus,  which  is  often  in  great  part  formed  by  it. 


E.  ABDOMINAL  GANGLIONS. 

§ 1895.  The  cord  by  which  the  limiting  ganglions  unite  is  always 
very  small  below  the  origin  of  the  splanchnic  nerve.  Sometimes  it  is 
entirely  deficient  in  some  points,  so  that  the  trunk  of  the  great  sympa- 


98 


DESCRIPTIVE  ANATOMY. 


thetic  nerve  is  there  interrupted  1 ) and  the  limiting  ganglions  form  one 
and  the  same  series  with  the  abdominal  ganglions  and  plexuses  only 
by  intermediate  connections.  When  this  series  comes  on  the  lumbar 
vertebrae  it  goes  forward.  We  there  see  ganglions  which  are  much 
smaller,  more  remote  from  each  other,  and  less  constant  in  their  situa- 
tion than  those  hitherto  examined.  The  upper  is  always  larger  than 
the  others,  which  gradually  diminish  from  above  downward  and  often 
do  not  exist,  or  at  least  are  almost  invisible. 

The  upper  pelvic  ganglions  of  the  limiting  cord  are  a little  larger 
than  the  inferior  lumbar,  and  form  a series  which  converges  from  above 
downward.  There  are  usually  four  or  five,  the  lowest  of  which  is 
situated  forward  between  the  sacrum  and  the  coccyx,  and  anastomoses 
with  the  corresponding  ganglion  of  the  opposite  side  by  a shortened 
thin  filament  which  is  convex  downward. 

The  lumbar  and  pelvic  ganglions  are  united  by  some  filaments 
which  differ  from  those  existing  between  the  others  in  their  length  and 
also  in  their  number  and  size  ; for  there  are  usually  three  or  four  be- 
tween each  two  ganglions,  which  are  much  smaller  than  those  be- 
tween the  superior  ganglions. 

Their  external  branches  proceed  to  meet  the  lumbar  and  sacral 
nerves,  and  anastomose  with  their  anterior  branches  near  the  inter- 
vertebral and  sacral  foramina. 

Those  of  the  superior  lumbar  ganglions  have  a direction  oblique 
from  below  upward. 

The  middle  are  transverse,  and  the  superior  oblique  from  above 
downward.  The  latter  are  very  long,  the  first  very  short.  Some 
which  are  smaller  go  upward  to  the  psoas  muscle,  downward  to  the 
pyramidalis  and  to  the  levator  ani  muscles. 

The  lumbar  ganglions  give  off  some  internal  branches  which  go  to 
the  anterior  face  of  the  aorta,  and  contribute  to  form  the  aortic  plexus 
which  comes  from  the  superior  mesenteric  plexus.  Some  of  the  sacral 
ganglions  anastomose  together  before  the  sacrum  ; others  terminate 
in  the  hypogastric  plexus. 

The  series  of  limiting  ganglions  terminates  below  in  some  filaments 
which  radiate  from  the  last  of  them,  and  which  are  distributed  in  the 
lower  and  posterior  part  of  the  rectum. 

§ 1896.  Our  mode  of  describing  the  ganglionnary  nerve  differs  from 
that  hitherto  adopted  even  by  those  anatomists  who  consider  it  as 
■directly  opposed  to  the  rest  of  the  system,  for  they  generally  commence 
by  that  part  which  descends  along  the  vertebral  column,  by  the  ex- 
ternal ganglionnary  cord,  and  terminate  with  the  central  portion. 

(1)  This  has  been  seen  twice  by  Haller  (Elem.  phys.,  vol.  iv.  p.  261).  Bichat  has 
■also  made  this  remark  (Reck.  phys.  sur  la  vie  et  la  mort , p.  82),  and  uses  this  as  the 
principal  argument  in  favor  of  his  opinion,  that  the  sympathetic  nerve  does  not  form 
a continuous  trunk  from  the  head  to  the  pelvis.  Wrisberg  ( Obs.  anat.  de  ganglia 
plexuque  semilunari,  § 19,  in  the  Comm.  Geetting,  1779,  vol.  ii.  p.  102)  has  admitted 
this  arrangement  to  be  an  anomaly,  and  Weber  (Anat.  comp,  nervi  sympathy  p.  122 
regards  this  observation  as  doubtful. 


OF  THE  NERVOUS  SYSTEM. 


99 


Our  course  will  at  first  view  be  more  surprising,  because  we  have 
several  times  mentioned  that  there  is  no  manifest  contrariety  between 
the  two  nervous  systems. 

In  fact  the  ganglionnary  nerve  is  only  the  highest  development  of  a 
form  which  has  passed  through  several  gradations.  We  may  consider 
the  diaphragmatic  nerve  as  the  first  of  these  : this  arises  from  several 
cervical  pairs,  and  passes  some  distance  to  go  to  a voluntary  muscle, 
the  diaphragm,  the  principal  agent  in  respiration.  This  formation  is 
still  more  developed  in  the  four  posterior  cerebral  nerves,  particularly 
in  the  pneumo-gastric,  which  forms  plexiform  anastomoses  with  the 
superior  cervical  nerves,  descends  along  the  neck,  is  distributed  to  the 
organs  of  respiration,  and  descends  to  the  stomach  in  the  abdominal 
cavity.  The  whole  course  of  this  nerve  favors  our  analogies  still  more, 
inasmuch  as  it  forms  numerous  plexuses  whence  branches  proceed  to 
the  organs. 

The  ganglionnary  nerve,  if  we  except  some  filaments  which  arise 
perhaps  from  the  pituitary  gland,  does  not  commence  directly  at  the  cen- 
tre of  the  nervous  system,  but  from  several  of  the  cerebral  and  from  all 
the  spinal  nerves.  It  descends  lower  than  the  pneumo-gastric  nerves, 
gives  some  filaments  to  all  those  organs  of  vegetative  life  which  re- 
ceive none  from  this  latter,  and  frequently  anastomoses  with  the  two 
preceding.  The  plexiform  and  ganglionnary  structure  is  more  evident 
in  it  than  in  any  other  nerve,  so  that  even  the  inner  part  of  its  expan- 
sion exceeds  the  outer  ; and  hence  from  its  form,  situation,  and  con- 
nections with  the  encephalon  and  spinal  marrow,  it  may  be  regarded 
as  the  trunk  of  the  nerve,  as  is  generally  admitted,  and  thus  the  inner 
part  is  considered  the  central  portion. 

These  are  our  reasons  for  departing  from  the  common  course,  al- 
though the  anatomical  and  the  physiological  relations  of  the  gangli- 
onnary nerve  prove  that  it  is  dependent  on  the  centre  of  the  nervous 
system,  being  connected  with  it  by  its  outer  part. 


CHAPTER  IV. 


DIFFERENCES  PRESENTED  BY  THE  NERVES  DURING  THEIR 
DEVELOPMENT. 

§ 1897.  The  differences  presented  by  the  nerves  during  their  deve- 
lopment have  been  but  slightly  studied,  and  we  have  but  few  observa- 
tions which  refer  to  them.  Not  having  had  sufficient  opportunities  of 
obtaining  well  preserved  human  fetuses,  we  cannot  add  as  many  re- 
marks as  are  desirable  to  those  already  existing. 

We  may  state  on  this  subject  the  following  corollaries  : 

1st.  All  the  nerves  are  not  developed  with  equal  rapidity  in  respect 
to  color,  texture,  and  consistence.  The  spinal  generally  increase 


100 


DESCRIPTIVE  ANATOMY. 


faster  than  the  cerebral  nerves.  We  have  found  them  perfectly  white 
and  evidently  fibrous  in  the  fetus  of  six  months,  while  the  cerebral 
nerves  were  gray.  The  fibrous  texture  and  color  are  developed  latest 
in  the  optic  nerves.  At  six  months  it  is  much  larger  than  the  other 
encephalic  nerves,  and  even  at  the  ninth  month  of  pregnancy  it  is  still 
as  gray  as  the  rest  of  the  cortical  substance,  is  very  soft,  and  presents 
no  appearance  of  fibres.  We  have  not  yet  been  ablctD  determine  if  it 
whitens  before  birth  ; it  however  experiences  this  change  early,  for  in 
two  children  one  month  old  we  have  found  it  perfectly  white  in  all  its 
course,  except  most  of  the  portion  between  the  decussation  and  the 
eye  ; the  latter  was  entirely  white  before  the  decussation,  gray  on  the 
outside  and  white  on  the  inside  in  the  centre  ; finally  totally  gray  for- 
ward. 

We  may  conclude  from  these  facts  that  the  nerves  complete  their 
development  from  within  outward  and  from  behind  forward.  This 
proposition  applies  both  to  the  different  nerves  and  to  the  same  nerves 
in  different  parts  of  the  body.  It  is  then  very  curious  that  the  olfac- 
tory nerve  which  is  the  most  anterior  remains  almost  entirely  gray 
during  life,  and  constantly  preserves  this  tint  in  its  whole  anterior  part. 
This  law  seems  to  be  general,  for  we  have  since  met  with  it  in  fetuses 
of  the  hog  and  cat. 

We  have  also  found  the  great  root  of  the  trifacial  nerve  entirely  gray 
in  the  fetus  of  eight  months. 

2d.  The  following  remarks  are  applicable  to  the  other  differences 
presented  by  the  nerves  : 

Among  the  spinal  nerves  we  have  found  in  a great  many  fetuses 
the  crurai  nerve  divided  on  emerging  from  the  pelvis  into  its  tibial  and 
peroneal  branches,  which  were  the  more  distinct  the  younger  the  fetys. 

Before  the  end  of  the  fifth  month  of  pregnancy  they  were  not  united 
so  intimately  as  they  are  at  an  advanced  age  ; hence  this  arrangement, 
which  is  abnormal  in  the  adult,  is  normal  during  the  early  periods  of 
existence.(l)  We  have  not  been  able  as  yet  to  observe  any  difference 
in  the  other  spinal  nerves 

The  trifacial  nerve  differs  from  what  it  is  in  the  adult  : 

1.  In  the  number  of  its  cords,  which  are  at  first  fewer.  In  the  fetus 
of  eight  months  there  are  only  eighteen  in  the  large  root,  while  there 
are  from  twenty-eight  to  thirty  in  a child  when  bom. (2) 

2.  The  texture  of  its  ganglionnary  plexus  is  less  fibrous.  We  have 
found  structure  of  this  plexus  was  homogeneous  at  the  sixth  month 
of  pregnancy. 

These  two  peculiarities  may  be  referred  to  the  same  principle,  the 
imperfect  development  of  the  nervous  tissue. 

(1)  We  have'  already  said  that  this  arrangement  is  curions  as  analogous  with  the 
mammalia,  but  did  not  intend  to  assert  that  it  is  common  to  all  these  animals. 

(2)  Vesting,  Obs.  anal.,  no.  viii. — Sœmmerring,  De  basi  cncephali,  § 60. — Nie- 
meyer,  in  Keil,  Archiv,  f ür  die  Physiologie , vol.  xi.,  p.  54. 


OF  THE  NERVOUS  SYSTEM. 


101 


The  olfactory  nerve  is  at  first  proportionally  much  larger  ; at  the 
same  time  it  is  rounded,  thicker,  and  shorter. 

Until  the  sixth  month  there  is  within  it  a cavity  which  communi- 
cates with  the  lateral  ventricles  of  the  cerebrum. 

These  are  two  remarkable  analogies  with  the  mammalia. 

In  the  full  grown  fetus  its  external  root  is  evidently  medullary.  We 
perceive  also  some  medullary  striæ  on  the  lower  face  of  the  nerve,  but 
there  is  no  trace  of  the  medullary  band  which  represents  its  internal 
root. 

In  the  early  periods  of  fetal  existence  the  great  sympathetic  nerve  is 
more  developed  in  proportion  to  the  body  than  almost  any  other  part  of 
the  nervous  system.  It  is  very  remarkable  that  the  large  limiting  gan- 
glions are  so  near  each  other,  particularly  in  the  chest,  that  they  form 
an  uninterrupted  series.  The  splanchnic  nerve  is  also  proportionally 
much  thicker  than  in  the  adult. 

At  about  the  middle  of  fetal  existence  this  nerve  has  diminished 
much,  and  then  presents  very  nearly  the  proportions  which  continue 
during  life.(l) 


CHAPTER  V. 

PARALLEL  BETWEEN  THE  DIFFERENT  NERVES. 

1.  BETWEEN  THE  SPINAL  AND  THE  ENCEPHALIC  NERVES. 

§ 1898.  The  spinal  and  encephalic  nerves  are  generally  strictly 
opposed  to  each  other,  and  are  distinguished  by  characters  mentioned 
previously  (§  170)  ; but  the  differences  between  them  are  not  so  dis- 
tinct as  is  asserted.  First  those  which  truly  exist  do  not  prevent  us 
from  considering  the  encephalic  nerves  in  the  condition  of  spinal  nerves, 
and  from  demonstrating  that  they  are  only  modifications  of  the  latter, 
and  from  investigating  the  cause  of  these  modifications. 

All  the  encephalic  nerves  are  portions  of  spinal  nerves  which  are 
not  united  in  a single  trunk  like  the  latter,  but  are  developed  as  so 
many  separate  nerves.  Tins  modification  of  the  primitive  type  de- 
pends on  the  development  of  the  centre  of  the  nervous  system  within 
the  skull  and  on  that  of  the  skull  itself,  which  mechanically  separates 
the  different  groups  of  the  roots  of  the  nerves  at  their  origin  and  in 
their  course. 

It  also  depends  on  special  organs,  those  of  the  senses,  which  are  de- 
veloped in  the  skull,  the  roots  of  which  are  formed  by  the  nerves  that 
go  to  them,  and  which  are  perfect  in  the  direct  ratio  of  the  development 
of  their  special  nerves.  Comparative  anatomy  demonstrates,  at  least 

(1)  Lobstein  has  given  a history  of  the  evolution  of  the  ganglionnary  nerve  in  the 
fetus,  and  the  modifications  it  experiences  as  age  advances  (Joe.  cit.,  p.  47-56.) 

Vol.  III.  14 


102 


DESCRIPTIVE  ANATOMY. 


in  regard  to  several  organs  of  the  senses,  that  new  nerves  are  not 
formed  for  them,(l)  hut  only  that  single  branches  arising  from  a spe- 
cial part  of  the  encephalon  become  trunks.  In  fact  we  see  several 
nerves,  especially  among  those  of  tire  organs  of  the  senses,  which  form 
separate  trunks  in  superior  animals,- are  only  subordinate  branches  in 
the  inferior  animals.  This  is  the  case  particularly  with  the  trifacial 
nerve  ; and  this  is  much  more  evident  the  more  inferior  the  animal. 

This  development  of  portions  of  nerves  which  raises  them  to  the 
rank  of  distinct  nerves  is  gradually  increased  from  the  posterior  to  the 
anterior  extremity  of  the  cerebrum.  It  is  manifested  in  the  posterior 
pairs  only  by  the  want  of  union  between  the  anterior  and  posterior 
roots  ; but  the  anterior  roots  seem  to  be  formed  from  the  fact  that  single 
fasciculi  appear  to  be  the  proper  nerves. 

The  nervous  system  then  follows  precisely  the  same  type  as  the 
other  systems,  particularly  the  osseous  ; for  the  bones  of  the  skull  are 
more  similar  to  the  vertebrae  the  more  posteriorly  they  are  situated,  and 
the  dissimilarity  between  them  and  the  vertebrae  which  gradually  in- 
creases from  behind  forward,  depends  principally  upon  the  fact  that 
simple  portions  of  the  vertebrae  have  become  sufficiently  developed  to 
be  considered  distinct  pieces  of  bone. 

In  this  view  of  the  subject,  we  should  consider  the  last  four  cerebral 
pairs,  the  accessory,  the  pneumo-gastric,  the  glosso-pharyngeal,  and 
the  hypoglossal  nerves,  as  so  many  sections  of  one  and  the  same  nerve, 
the  posterior  of  which  is  formed  by  the  first  three  nerves,  and  the  an- 
terior by  the  fourth.  In  fact,  the  accessory,  the  pneumo-gastric,  and 
the  glosso-pharyngeal  nerves,  arise  by  an  uninterrupted  series  from  the 
posterior  cord  of  the  spinal  marrow,  and  emerge  from  the  skull  through 
the  same  opening.  They  thus  form  in  the  skull,  trunks,  the  external 
parts  of  which  are  separate  from  each  other,  and  generally  pass 
through  the  dura-mater  in  different  points.  But  this  is  far  from  being 
the  case  with  the  accessory  nerve,  and  even  when  it  is,  the  accessory 
is  adapted  to  the  pneumo-gastric  nerve  so  intimately,  that  they  form 
a single  trunk.  Beside,  after  the  two  nerves  separate,  the  inner 
branch  of  the  ' accessory  nerve  again  unites  with  the  eighth  pair,  and 
continues  with  it.  The  glosso-pharyngeal  nerve  also  anastomoses  by 
one  filament  even  within  the  cranium,  with  the  pneumo-gastric  nerve, 
and  after  leaving  the  skull,  they  communicate  by  several  other  fila- 
ments. It  is  curious  that  the  accessory  and  pneumo-gastric  nerves 
on  one  side,  the  glosso-pharyngeal  nerve  on  the  other,  and  just  before 
where  it  unites  with  the  two  preceeding,  form  ganglions  near  the 
place  where  they  emerge  from  the  skull,  exactly  as  do  the  posterior 


(1)  See  on  this  subject  the  important  memoir  of  Treviranus,  in  which  he  proves 
that  the  nerves  of  the  fifth  pair  take  the  place  of  those  of  very  important  sense*  in 
some  animals,  and  that  there  is  in  these  animals  some  org-ans  of  sense  very  different 
from  those  of  man,  the  nerves  of  which  are  the  branches  of  the  fifth  pair  (Sur  les 
nerfs  de  la  cinquième  paire,  considérés  comme  organes  ou  /conducteurs,  de  sensations  ; 
in  the  Journ.  oomplém.  dessc.  méd.,  vol.  xv.  p.  207).  Ilis  observations  have  been 
confirmed  since  by  Magendie.  F.  T. 


OF  THE  NERVOUS  SYSTEM. 


103 


roots  of  the  spinal  nerves  ; nor  ought  we  to  omit  mentioning  that  the 
posterior  root  of  the  superior  cervical  nerve  often  joins  the  accessory, 
which  then  assumes  the  character  of  the  posterior  root,  which  cha- 
racter is  also  expressed  very  distinctly  by  its  situation  behind  the  liga- 
mentum  denticulatum. 

The  glosso-pharyngeal  nerve,  the  anterior  root  of  this  pair  of  nerves, 
arises  from  the  anterior  cord  of  the  medulla  oblongata,  like  the  other 
anterior  roots  of  the  spinal  nerves,  and  as  its  origin  is  situated  more 
inward  and  forward,  it  also  emerges  from  the  skull  through  an  open- 
ing situated  more  inward  and  forward.  In  fact,  it  leaves  the  skull 
through  a special  opening  in  the  occipital  bone,  rather  distant  from 
that  through  which  the  other  three  pass.  But  this  difference  from 
the  spinal  nerves  depend  on  the  two  causes  mentioned  above,  and  we 
see  in  it  only  a greater  development  of  the  arrangement  of  the  anterior 
and  posterior  roots  of  the  spinal  nerves  which  pass  through  distinct 
openings  in  the  dura-mater  before  uniting  ; finally,  the  glosso-pharyn- 
geal  nerve  just  after  leaving  the  skull,  is  adapted  directly  to  the  trunk  of 
the  pneumo-gastric  nerve,  anastomoses  with  it  by  some  filaments,  par- 
ticularly below  its  ganglion,  and  goes  forward,  while  the  eighth  pair, 
united  with  the  other  two,  is  distributed  principally  below  and  back- 
ward. We  ought  not  to  forget  that  this  nerve  never  forms  the  gan- 
glion alone,  and  rarely  or  never  communicates  with  the  ganglion  of 
the  three  posterior  nerves. 

The  fasciculi  of  this  nerve,  like  those  of  the  first  three,  frequently 
emerge  from  the  dura-mater,  and  sometimes  from  the  skull,  through 
distinct  openings,  but  this  difference  is  'not  essential,  for  if  the  fasciculi 
of  each  of  the  roots  of  the  spinal  nerves  unite  in  man  before  that  each 
root  passes  through  the  dura-mater,  in  the  mammalia,  they  perforate 
this  membrane  in  three  or  four  points,  and  before  uniting,  as  is  also 
true  of  the  nerves  of  which  we  speak.  Comparative  anatomy  fur- 
nishes several  other  facts  which  prove  the  parallel  stated  by  us.  In 
fishes,  the  anterior  and  posterior  roots  of  the  spinal  nerves  emerge 
separately  from  the  spinal  column  through  special  openings,  so  that 
they  are  still  more  similar  to  the  cerebral  nerves  in  this  class  of  the 
animal  kingdom.  On  the  other  hand,  in  most  of  the  mammalia  the 
first  cervical  nerve,  and  even  the  second  in  some,  particularly  the  hog 
and  the  ox,  frequently  arise  entirely  from  the  anterior  cord  of  the 
spinal  marrow,  and  form  only  the  anterior  root  of  a spinal  nerve,  which 
does  not  emerge  through  a groove,  but  through  an  opening  in  the 
first  and  second  cervical  vertebræ.  In  almost  all  the  mammalia  the 
posterior  root  of  the  first  cervical  nerve  enlarges  into  a ganglion  long 
before  it  unites  with  the  anterior,  and’ before  the  nerve  passes  through 
the  first  cervical  vertebra.  The  ganglion  sometimes  divides,  as  we  have 
often  observed  in  the  hog  for  instance,  into  two  enlargements,  an  an- 
terior and  a posterior,  or  at  least  we  not  unfrequently  observe  a deep 
strangulation  at  its  centre  and  the  portion  of  the  posterior  root  between 
it  and  the  part  of  the  nerve  where  it  emerges  from  the  vertebral 
column,  forms  two  in  the  hog,  an  anterior  and  a posterior  ; f his  shows 


104 


DESCRIPTIVE  ANATOMY. 


that  in  this  animal,  except  in  the  first  cervical  nerve,  the  posterior  root 
tends  to  separate  from  the  anterior,  and  to  become  a distinct  and 
special  nerve. 

From  all  these  remarks  it  is  not  difficult  to  reduce  the  last  four  cere- 
bral pairs. 

Scemmerring  had  already  remarked  that  the  glosso-pharyngeal  nerve 
appeared  at  its  origin  like  each  of  the  spinal  nerves  ; hence,  it  ought 
not  to  be  separated  from  them  and  be  considered  an  encephalic 
nerve. (1)  The  same  anatomist  compared  the  origin  of  the  pneumo- 
gastric  to  that  of  the  spinal  nerves. (2)  Finally,  others  had  considered 
the  accessory  as  a spinal  nerve,  or  as  making  the  transition  from  the 
spinal  to  the  encephalic  nerves.  But  each  admits  that  these  compari- 
sons, founded  on  peculiarities  which  escape  the  eye,  have  no  connec- 
tion with  the  proposition  we  establish,  viz.  that  the  last  four  cerebral 
pairs  form  in  fact  only  one  encephalic  nerve,  the  posterior  root  of  which 
emerges  through  the  intervertebral  foramen,  situated  between  the 
last  and  the  last  but  one  of  the  vertebrae  of  the  skull  (the  occipital 
and  the  temporal  bones),  while  the  second  emerges  from  it  only 
through  the  last  cephalic  vertebra. 

The  reduction  of  the  other  eight  pairs  is  more  difficult.  Some, 
however,  the  common  and  the  external  motor,  evidently  have  the 
characters  of  anterior  roots,  or  at  least  of  portions  of  anterior  roots  ~ 
others,  as  the  auditory  and  the  superior  motor  nerve,  present  no  less 
manifestly  those  of  the  posterior  roots.  It  is  more  difficult  to  determine 
in  regard  to  the  rest.  We  may,  nevertheless,  compare  the  facial  with 
the  auditory  nerve,  and  consequently  with  tho  posterior  roots,  on 
account  of  its  course  and  the  nearness  of  its  origin,  even  as  the  origin 
and  the  course  of  the  trifacial  nerve  authorize  us  to  arrange  it  along 
the  anterior  roots.  As  to  the  two  anterior  pairs,  the  second  may  be 
compared  to  a posterior  root,  because  it  arises  from  the  tubercula 
quadrigemina  and  the  optic  beds,  and  the  first  may  be  compared  to  an 
anterior  root.  We  may  then  consider  four  pairs  as  anterior  roots,  and 
four  as  posterior  roots,  or  as  portions  of  these  roots.  It  is  now  easy  to 
to  refer  the  auditory,  the  facial,  the  trifacial,  and  the  motor  nerve,  to  a 
single  trunk.  When  we  follow  the  origin  of  the  facial,  trifacial,  and 
auditory  nerves  within  the  cerebrum  and  backward,  we  see  that  they 
singularly  approach  each  other.  In  regard  to  the  facial  and  the  audi- 
tory nerve,  we  must  mention  beside  the  nearness  of  their  origins,  the 
remark  of  Santorini,  that  we  can  trace  below  the  transverse  fibres  of 
the  annular  protuberance,  to  the  origin  of  the  auditory  nerve,  some 
fibres  which  from  their  progress  and  direction,  are  evidently  the  com- 
mencement of  the  facial  nerve. (3)  The  trifacial  nerve  which  partly 
arises  from  the  olivary  bodies,  blends  here  with  the  sixth  pair.  The 
common  motor  nerve  goes  from  before  backward  to  meet  all  these 

(1)  He  hast  encephali  ; in  Ludwiw,  lor.  cit.,  p.  103. 

(2)  Loc.  cit.,  p.  101. 

(3)  Septcmdec.  tab.  p.  23. 


OF  THE  NERVOUS  SYSTEM, 


105 


nerves  in  the  annular  protuberance.  The  superior  motor  nerve  and 
the  optic  nerve,  are  also  very  intimately  united  with  them  by  the  band 
which  extends  from  the  medulla  oblongata  to  the  tubercula  quadri- 
gemina. 

The  demonstration  is  most  difficult  with  regard  to  the  two  anterior 
nerves  ; still  the  short  distance  between  the  origins  of  the  external 
motor  and  optic  nerves,  indicate  that  the  latter  depends  on  the  others, 
and  the  anterior  commissure  imites  the  olfactory  and  the  optic  nerves. 

IL  PARALLEL  BETWEEN  THE  NERVES  OF  THE  UPPER  AND  LOWER  EX- 
TREMITIES. 

§ 1899.  The  nerves  of  the  upper  and  lower  extremities,  like  the 
bones,  the  muscles,  and  the  vessels,  are  formed  essentially  after  the 
same  type,  and  differ  only  by  slight  modifications  of  this  type,  which 
is  subject  to  the  same  laws  as  those  of  the  other  three  systems. 

At  first  view  the  number  of  the  pairs  of  nerves  which  unite  to  form 
the  nerves  of  the  two  extremities,  seem  to  differ  considerably,  as  there 
are  but  five  pahs  of  nerves  of  the  upper  extremities,  while  those  of  the 
lower  are  formed  by  ten.  This  difference,  however,  vanishes  on  strict 
examination.  In  fact,  all  the  cervical  nerves  are  evidently  arranged 
among  those  which  concur  to  form  the  brachial  plexus,  since  they  are 
all  united  and  changed  into  a real  plexus  like  all  the  lumbar  and 
sacral  nerves,  by  large  anastomoses  between  their  anterior  branches. 
Further,  the  difference  in  number  between  the  nerves  of  the  two  ex- 
tremities is  only  one  pair.  But  we  may  also  explain  this  apparent 
anomaly  by  considering  the  last  four  encephalic  nerves,  the  glosso- 
pharyngeal, the  accessory,  the  pneumo-gastric,  and  the  hypoglossal 
nerves  as  one  pair,  which  corresponds  to  the  branches  of  the  inferior 
sacral  nerves.  This  comparison  is  authorized  by  the  discussion  in  re- 
gard to  the  origin  of  these  four  nerves  which  we  have  mentioned,  and 
by  considering  the  manner  in  which  they  are  distributed.  In  fact, 
they  give  off  branches  to  the  tongue  and  -upper  part  of  the  intestinal 
-canal,  even  as  the  inferior  sacral  nerves  send  them  to  the  organs  of 
generation  and  to  the  lower  part  of  the  intestinal  canal. 

All  these  analogies  admitted,  the  number  of  pairs  of  nerves  in  the 
two  extremities  is  equal  : we  must  not,  however,  attach  much  im- 
portance to  this  uniformity  of  number,  nor  consume  time  in  endeavor- 
ing to  establish  it,  for  it  is  unimportant,  but  presents  itself  so  naturally, 
that  it  would  be  wrong  to  neglect  it. 

We  may  also  proceed  in  an  opposite  manner,  and  decompose  the  su- 
perior and  inferior  plexuses,  considering  separately  the  deep  cervical 
and  brachial  plexuses  above,  and  the  lombo-abdominal  and  sacral 
plexuses  below,  and  oppose  them  to  each  other.  This  is  Bichat’s 
method.  But  it  is  inferior  to  the  other,  because  it  obliges  us  to 
separate  parts  which  are  united. 

The  principal  common  relations  between  the  nerves  of  the  two  ex- 
tremities in  their  distribution,  are  as  follow  : 


106 


DESCRIPTIVE  ANATOMY. 


The  superior  cervical  nerves  are  distributed  to  the  muscles  and  in- 
teguments of  the  neck,  the  same  as  the  superior  lumbar  nerves  are  to 
the  muscles  and  skin  of  the  loins.  The  first  sends  some  branches  to 
the  skin  of  the  shoulder,  the  suprascapular  nerves,  while  the  second 
furnish  some  to  the  skin  of  the  haunch  and  the  arms. 

The  thoracic  nerves  correspond  to  the  obturator  nerve  by  their  high 
origin,  their  course  .below  the  bones  of  the  same  part,  and  their  distri- 
bution to  muscles  which  correspond. 

The  scapular  nerve  is  the  superior  gluteal. 

The  axillary  nerve  is  the  inferior  gluteal. 

The  nerves  which  are  distributed  lower  in  the  two  extremities'  differ 
much  more,  since  two  twigs  and  even  large  branches,  which  corres- 
pond in  their  mode  of  distribution,  arise  from  different  trunks.  The 
branches,  however,  are  the  same,  and  we  can  easily  explain  their  dif- 
ferences in  respect  to  origin. 

The  nerves  yet  to  be  compared  are  in  the  upper  extremity,  the  internal 
and  the  external  cutaneous  nerve,  the  radial,  the  median,  and  the 
ulnar  nerve  ; in  the  lower  extremity,  the  crural  and  the  sciatic  nerve. 

The  external  cutaneous  radial  nerves  correspond  to  the  crural  : the 
internal  cutaneous,  the  median,  and  the  ulnar  nerve,  to  the  sciatic. 

The  external  cutaneous  nerve  and  the  long  cutaneous  branch  of  the  ra- 
dial nerve,  are  evidently  thesuperior  and  inferior  internal  saphena  nerves 
of  the  lower  extremity,  since  they  descend  along  the  side  of  the  thumb 
and  of  the  large  toe,  which  is  the  internal  the  the  upper  limb  is  in  a 
moderate  degree  of  pronation,  and  is  always  so  in  the  lower  extremi.y 
when  it  is  at  rest. 

The  muscular  branches  of  the  crural  nerve  are  the  upper  branches 
of  the  radial  nerve.  They  are  distributed  in  the  extensor  muscles  of 
the  leg,  as  the  latter  are  in  those  of  the  fore-arm. 

The  analogy,  however,  between  the  radial  and  crural  nerves,  ceases 
there.  The  lower  branches  given  off  by  the  latter  are  represented  in 
the  leg,  but  come  there  from  the  sciatic  nerve. 

The  superior  and  posterior  cutaneous  nerves  of  this  latter,  very  evi- 
dently correspond  to  the  upper  branches  of  the  internal  cutaneous 
nerve  of  the  arm,  since  they  descend  on  the  outer  or  fibular  side  of 
the  little  toe,  as  these  latter  do  on  the  ulnar  side  of  the  little  finger. 

The  tibial  nerve  corresponds  principally  to  the  median  and  a part  of 
the  ulnar  nerve.  The  peroneal  represents  the  lower  part  of  the  ulnar 
nerve,  and  still  more  that  of  the  radial.  We  may  compare  the  posterior 
cutaneous  branch  of  the  tibial  nerve,  which  so  frequently  arises  from 
the  peroneal  nerve,  to  some  ramifications  of  the  internal  cutaneous 
brachial  nerve. 

The  muscular  branches  given  by  this  nerve  to  the  leg  correspond  to 
those  sent  by  the  median  nerve  to  the  muscles  of  the  fore-arm. 

The  superficial  plantar  nerve  is  represented  by  the  superficial  palmar 
branch  of  the  median  nerve. 

The  internal  plantar  nerve  corresponds  exactly  to  the  palmar  branch 
of  the  median  nerve. 


OF  THE  NERVOUS  SYSTEM. 


107 


The  external  plantar  nerve  is  represented  by  the  palmar  branch  of 
the  ulnar  nerve. 

The  muscular  branch  of  the  peroneal  nerve  corresponds  to  the  mus- 
cular branches  of  the  radial  and  ulnar  nerves  of  the  fore-arm. 

The  cutaneous  branch  which  is  distributed  in  the  back  of  the  foot 
corresponds  by  its  external-  twig  to  the  dorsal  branch  of  the  ulnar 
nerve,  and  by  the  internal  to  that  of  the  radial  nerve. 

§ 1900.  The  differences  here  remarked  may  be  easily  explained  : 

1st.  Some  nerves  which  arise  as  distinct  trunks  in  the  upper  extre- 
mity are  one  nerve  in  the  lower. 

2d.  Some  branches  arise  from  different  trunks. 

These  two  anomalies  depend  on  the  general  difference  in  the  form 
of  the  two  extremities. 

1st.  As  the  fibula,  from  its  smallness  and  its  want  of  articulation  with 
the  tibia,  seems  reduced  in  man  to  a simple  constituent  part  of  the 
tibia  ; as  several  muscles  of  the  leg  are  attached  in  a common  ten- 
don, while  others  situated  hi  the  fore-arm  in  the  upper  extremity  are 
found  in  the  sole  of  the  foot  ; as  the  external  cutaneous  vein  of  the 
pelvic  limb  unites  with  the  internal  at  the  knee,  while  these  two  veins 
remain  distinct  to  the  axilla  in  the  upper  extremity  ; finally  as  the  arte- 
ries often  divide  very  high  in  the  upper  extremity,  while  this  anomaly 
is  very  rare  in  the  lower,  so  likewise  the  nervous  trunks  which  sepa- 
rate very  early  in  the  arm,  long  remain  united  in  the  leg. 

Farther,  the  tibial  and  peroneal  nerves  are  not  only  sometimes  dis- 
tinct in  the  pelvis  as  those  of  the  upper  extremity  sometimes  are  in  the 
axilla  : but  also  the  cutaneous  nerves  of  the  arm  are  frequently  simple 
branches  of  the  three  larger  nerves.  The  difference  mentioned  above 
in  the  crural  nerve  during  its  development,  also  establishes  a greater 
analogy  between  the  two  limbs  in  the  early  periods  of  life  than  at  a 
more  advanced  age. 

2d.  The  difference  in  origin  depends  partly  on  the  preceding  fact, 
partly  also  on  the  difference  in  the  direction  and  situation  of  the  two 
extremities.  If  the  arm  is  in  the  state  of  pronation,  and  thus  possesses 
a direction  similar  to  that  of  the  lower  extremity,  these  differences  are 
explained  with  facility. 

The  radial  nerve  is  then  drawn  up  as  high  as  the  elbow,  so  that  we 
may  imagine  it  to  terminate  here,  and  that  its  lower  part  unites  with 
the  ulnar  nerve. 

The  antibrachial  parts  of  the  median  and  ulnar  nerves  are  also  ap- 
proximated, and  they  blend  in  a single  trunk  which  divides  into  two- 
branches  at  the  palm  of  the  hand. 


I • ' . , 1 N 


BOOK  VI. 


SPLANCHNOLOGY. 

§ 1901.  Splanchnology,  or  the  branch  of  anatomy  which  treats  of 
the  apparatus  for  the  functions,  includes  the  description  of  the  most 
complex  parts  of  the  organism,  those  formed  by  the  union  of  a greater 
or  less  number  of  simple  organs  or  systems.  We  cannot  consider  these 
as  belonging  to  the  class  of  those  already  mentioned,  as  they  differ  too 
much  from  these  latter  or  from  each  other.  We  must  however  re- 
mark that  they  may  .finally  be  referred  in  respect  to  their  essential 
characters  to  the  cutaneous  and  glandular  systems. 

In  regard  to  their  functions  they  may  be  divided  into  two  classes, 
one  of  which  establishes  an  immaterial,  the  other  a material  connection 
between  the  organism  and  the  external  world.  The  first  are  the 
organs  of  sense,  the  others  are  properly  termed  the  viscera. 

The  organs  of  the  se7ises  perceive  actively  the  impressions  of  quali- 
ties belonging  to  the  body  which  they  contribute  to  form,  or  to  external 
objects.  They  transmit  them  to  the  brain  by  means  of  their  nerves, 
and  cause  in  this  viscus  the  formation  of  ideas , that  is,  they  there 
produce  modifications  of  the  principle  of  the  mind,  of  which  it  is  the  im- 
mediate organ. 

Some  of  the  viscera  receive  foreign  external  substances,  others  re- 
move all  that  the  vital  powers  have  rendered  useless,  or  separate  parts 
proper  to  form  similar  new  bodies,  that  is,  they  remove  from  the  organ- 
ism all  that  is  useless  and  which  cannot  serve  to  preserve  the  species. 
Some  of  these  organs,  as  the  intestinal  canal  and  the  lungs,  perform 
both  of  these  functions  at  the  same  time  ; others,  as  the  kidneys  and 
genital  organs,  serve  only  for  the  excretory  function  ; they  all  have 
this  in  common,  that  they  form  new  substances,  and  that  they  thus  pre- 
serve the  individual  in  the  normal  state.  The  substance  formed  by  the 
genital  organs  serves  also  and  in  a special  manner  to  preserve  the 
species. 

However  different  the  results  and  the  mode  of  action  of  the  organs 
of  sense  and  the  apparatus  of  formation  may  be,  the  first  are  in  regard 
to  mind  exactly  the  same  as  are  the  second  in  relation  to  the  body. 
Farther  the  inferior  senses,  those  of  smell,  taste,  and  touch,  which  are 
the  bases  of  all,  insensibly  establish  the  transition  from  the  superior 
senses,  those  of  sight  and  hearing,  to  the  proper  viscera,  both  in  respect 
to  their  form  and  situation,  and  to  their  mode  of  action.  We  may  also 
Vol.  III.  15 


110 


DESCRIPTIVE  ANATOMV. 


admit  that  the  organs  of  sense  and  the  viscera  have  several  characters 
in  common  ; these  are  : 

1st.  They  are  developments  of  the  cutaneous  system. 

2d.  They  are  mostly  or  entirely  situated  ir;  more  or  less  perfect  bony 
cavities. 

3d.  They  are  prolonged  outward  by  valvular  folds  of  the  skin,  which 
are  provided  with  simple  glands  and  hairs. 

4th.  There  is  only  one  or  at  most  but  two  : in  the  former  case  they 
are  situated  so  that  the  median  line  divides  them  into  two  equal  parts  j 
in  the  second  there  is  only  one  on  each  side,  a right  and  a left. 

As  the  direct  organ  of  the  spiritual  principle  is  that  which  we  consi- 
dered last,  it  is  most  convenient  to  examine  first  the  organ  of  the  most 
intellectual  sense,  that  of  hearing,  and  next  to  treat  of  that  of  sight, 
that  of  smell,  and  lastly  the  organ  of  taste,  which  forms  a part  of  the 
digestive  apparatus.  After  describing  this  apparatus  we  shall  pass  to 
the  organs  of  respiration  and  of  voice,  then  to  those  of  the  urinary  se- 
cretion, and  lastly  to  those  of  generation  and  the  history  of  the  fetus. 


SECTION  I. 

OF  THE  ORGANS  OF  SENSE. 

§ 1902.  All  the  organs  of  the  senses(  1)  are  similar  in  the  following 
characters  : 

1st.  They  are  situated  in  the  head.  The  organ  of  hearing  is  placed 
the  farthest  backward  and  belongs  entirely  to  the  skull  ; it  is  also 
situated  the  most  on  the  side,  and  its  two  lateral  portions  are  entirely 
distinct  from  each  other.  The  cavity  occupied  by  the  eye  is  partly 
formed  by  the  bones  of  the  skull  and  mostly  by  those  of  the  face. 
That  of  the  olfactory  organ  belongs  still  more  to  the  face,  in  fact  al- 
most exclusively  to  it,  since  the  ethmoid  bones  form  less  of  the  skull 
than  of  the  face.  The  cavity  of  the  mouth  is  formed  only  by  the  bones 
of  the  face.  The  right  and  left  portions  also  gradually  approach  each 
other  from  the  organ  of  hearing  to  that  of  taste,  so  that  they  finally 
blend  in  the  tongue. 

2d.  They  are  all  connected  by  short  and  large  nerves  with  the  ence- 
phalon. The  auditory  is  proportionally  the  shortest  and  largest  nerve. 
It  arises  from  the  calamus  scrip torius  as  from  a distinct  cavity,  so  that 

(1)  A.  Molinetti,  Dissertaliones  anatomicœ  et  pathologicæ  de  sensibus  et  eorum  or- 
ganisa Padua,  1669. — Casserio,  Pantæsthesejon , hoc  est  de  quinque  sensibus  liber, 
organorum  fabrieam,  usum  et  actionem  conlinens , Venice,  1699. — Haller,  De  sensibus 
in  gcncre,  Gottingen,  1742.— Lecat,  Traité  des  sens,  Amsterdam,  1744. — Sœmmer- 
ring-,  Abbildungen  dec  menschlichen  Sinnorgane,  Francfort,  1809. 


OF  THE  EAR, 


111 


ïïo  other  nerve  of  the  organs  of  sense  is  connected  so  intimately  with 
the  mass  of  the  encephalon. 

3d.  Ml  receive  their  nerves  from  at  least  two  pairs.  The  larger 
nerve  is  termed  the  nerve  of  sense , and  the  smaller  the  accessory  nerve. 
In  the  organs  of  hearing,  smell,  and  taste,  the  nerve  of  sense  forms  as 
many  distinct  pairs,  the  auditory,  optic,  and  olfactory  nerves,  while  in 
that  of  taste  it  is  only  a branch  of  the  trifacial  nerve,  which  is  also  the 
common  trunk  of  the  accessory  nerves  ; but  this  includes  also  the 
hypoglossal,  the  glosso-pharyngœal  and  the  facial,  the  three  motor 
and  the  ganglionnary  nerves.  The  names  of  several  of  these  nerves 
prove  that  the  accessory  nerves  serve  principally  to  excite  the  motions 
of  the  organs  of  sense.  The  olfactory  nerve  is  the  only  one  which  is 
to  a certain  extent  an  exception  to  the  rule,  since  its  proper  accessory 
nerves,  like  its  nerve  of  sense,  are  distributed  in  the  mucous  membrane 
of  the  nose.  The  nerves  of  sense  and  the  accessory  nerves  are  not 
necessarily  connected  ; these  connections  do  not  exist  in  the  organs  of 
sight  and  hearing.  They  are  slight  and  probably  inconstant  in  the 
organ  of  smell,  and  are  well  developed  only  in  the  tongue,  which  is 
the  most  similar  to  the  general  organ  of  touch. 

4th.  The  proper  nerves  of  sense  expand  more  or  less  evidently  as  a 
thin  membrane , which  is  covered  directly  by  a fluid  above  which  is  a 
tissue  similar  to  the  epidermis. 

5th.  They  all  communicate  by  ducts  more  or  less  broad,  the  prolon- 
gations of  the  internal  cutaneous  membrane  which  make  part  of  them, 
and  which  perform  a part  as  much  more  important  in  their  organiza- 
tion the  less  they  are  developed.  The  more  similarity  there  is  between 
them,  as  between  the  organs  of  taste  and  smell,  the  more  loose  and  ex- 
tensive the  communication,  so  that  so  they  really  form  but  one  in  the 
early  periods  of  life,  at  which  time  the  roof  of  the  palate  which  will 
separate  the  last  two  from  each  other  is  not  yet  formed.  The  com- 
munication between  these  two  organs  of  sense  and  the  others  is  more 
marked  the  nearer  the  fetus  is  to  its  period  of  formation. 

In  fact  the  cutaneous  system  is  more  or  less  evidently  the  prototype 
of  all  the  organs  of  sense,  and  the  external  integuments  are  the  seat  of 
sensation,  as  the  hand  is  that  of  the  special  modification  of  the  general 
sensation  termed  the  touch. 


CHAPTER  I. 

OF  THE  ORGAN  OF  HEARING. 

§ 1903.  The  organ  of  hearing, (l)  or  the  ear,  is  situated  at  the 
centre  of  the  side  and  the  base  of  the  skull  within  and  on  the  surface 

(1)  Fallopius,  in  his  Obs.  anat.,  Venice,  1561  ; Opp.  omn.,  vol.  i.,  tr.  ii.— Eustachius, 
De  auditus  organo  ; in  the  Opusc.  anat.,  Venice,  1564. — Fabricius  d’Aquapendente, 


112 


DESCRIPTIVE  ANATOMY. 


of  t lie  temporal  bone.  This  organ,  the  most  noble  and  the  most  intel- 
lectual of  the  senses,  belongs  entirely  to  the  skull.  It  is  connected 
with  the  encephalon  more  directly,  and  is  protected  better  against  ex- 
ternal injuries  than  any  other  of  the  senses. 

It  is  formed  of  a considerable  number  of  parts  differing  very  much  in 
their  form  and  texture,  and  which  may  be  divided  generally  into  two 
sections,  comprehending  the  external  and  the  internal  ear. 


ARTICLE  FIRST. 


EXTERNAL  EAR, 

§ 1904.  The  external  ear,  oriente , Ch.  (auris  externa), (l)  is  formed 
by  the  cartilage  of  the  ear,  the  cartilaginous  portion  of  the  external 
auditory  passage,  and  several  muscles  which  are  attached  to  the  dif- 
ferent regions  of  the  auricular  cartilage.  All  these  parts  are  covered 
by  the  common  integuments. 

A.  CARTILAGE  OF  THE  EAR. 

§ 1905.  The  cartilage  of  the  ear  ( cartilago  auris), (2)  considered 
generally,  is  formed  like  a short  tunnel  with  a broad  oval  opening 
larger  from  above  downward  than  from  before  backward.  This  sur- 
face is  very  uneven  from  several  prominences  and  depressions  which 
circumscribe  this  opening. 

De  visione,  voce  et  auditu,  Venice,  1688.— J.  Mery,  Description  exacte  de  l'oreille, 
l’aria,  1681. — Duverney,  Traité  de  l’organe  de  l’ouïe,  contenant  la  structure,  les 
usages  et  les  maladies  de  toutes  les  parties  de  L’oreille,  Paris,  1683. — C.  G.  Schel- 
hammer,  De  auditu  liber  anus , Leyden,  1684.  A.  M.  Vasalva,  Tradatus  de  aure 
humanâ,  Bologna,  1704. — R.  Vieussens,  Traité  delà  structure  de  l’oreille,  Toulouse, 
1714. — J.  F.  Casscbohm,  Tradatus  quatuor  de  aure  humanâ,  Halle,  1734;  Trac- 
tatus  quintus  et  sextus , Halle,  1735. — Morgagni,  Ep.  anat.,  ep.  iv.,  v.,  vii.,  xii.,  xiii. 
—Geoffroy,  Dissertations  sur  l’organe  de  l'ouïe  de  l’homme,  des  reptiles  et  des 
poissons,  Amsterdam,  1788. — C.  P.  C.  Wildberg,  Versuch  einer  anatomisch  physiolo- 
gischpathologischen Abhandlung  über  die  Gehörwerkzeuge  des  Menschen,  Jena, 
1795. — Soemmerring,  Abbindungen  der  menschlichen  Gehörorgane,  Francfort,  1806. 
— J.  S.  Schroeter,  Das  menschliche  Ohr,  nach  den  Abbildungen  Soemmerrings  ver- 
grössert  dargestellt,  Weimar,  1811. — J.  Cunningham. — Saunders,  The  anatomy  of 
the  human  ear,  illustrated  by  a series  of  engravings  of  the  natural  size,  with  a trea- 
tise on  the  diseases  ofthat  organ,  the  causes  of  deafness,  and  their  proper  treatment, 
1817. — C.  S.  Pohl,  Exposili)  generalis  anatomica  organis  auditus  per  classes  ani- 
malium,  Vienna,  1818. — T.  H.  Weber,  De  aure  et  auditu  hominis  el  animalium, 
Leipsic,  1830. — J.  Van  der  Hœven,  Diss.  de  organo  auditus  in  homine,  Utrecht, 
1822.  * y 

(1)  D.  Santorini,  De  aure  ‘ inteymfo^m  the  Observât,  anatom.,  Venice,  1724,  ch. 

ii. 

(2)  11.  S.  Albinus,  De  cartilagine  auriculœ  ; in  the  Annot.  academ.,  lib.  vi.,  cap. 
vii.,  tab.  iv. 


OF  THE  EAR. 


113 


1st.  The  most  external  eminence  which  mostly  surrounds  all  the 
others  is  called  the  helix. 

It  begins  at  the  centre  of  the  anterior  edge  of  the  external  ear,  goes 
first  from  below  upward  to  the  upper  extremity  of  the  auricular  car- 
tilage, then  curves  backward,  and  finally  descends  to  the  posterior  part 
of  the  circumference  of  the  ear  and  terminates  imperceptibly  at  its 
lower  extremity. 

2d.  A second  eminence  surrounded  by  the  preceding,  and  termed 
the  anthelix.  It  begins  below  and  behind  near  the  lower  extremity  of 
the  helix,  goes  upward  and  forward,  separates  a little  from  this  latter 
and  divides  at  its  upper  and  anterior  extremity  into  a superior  and  an 
inferior  branch,  which  extend  to  near  the  ascending  portion  of  the 
helix  where  they  gradually  terminate. 

3d.  Opposite  the  commencement  of  the  helix  is  a third  square  emi- 
nence which  forms  the  anterior  and  inferior  part  of  the  cartilage  of  the 
ear.  It  is  termed  the  tragus. 

4th.  Opposite  the  tragus  we  observe  posteriorly  a similar  promi- 
nence termed  the  antitragus , separated  by  a groove  from  the  prece- 
ding. The  helix  and  the  anthelix  terminate  here. 

§ 1906.  The  depressions  between  these  different  prominences  are  : 

1st.  The  scaphoid  or  navicular  fossa  ( fossa  scaphoidea),  a slight 
depression  which  is  concave  forward,  convex  backward,  and  which 
extends  between  the  posterior  part  of  the  helix  and  anthelix. 

2d.  The  anonymous  triangular  or  oval  fossa  ( fossa  anonyma,  s. 
triangularis , s.  ovalis ),  which  extends  between  the  two  branches  of 
the  anthelix. 

3d.  The  concha  ( concha  auris ),  a deep  cavity  which  serves  as  the 
entrance  to  the  cartilaginous  portion  of  the  auditory  passage.  It  is 
situated  between  the  helix,  the  tragus,  and  the  antitragus. 

4th.  The  groove  of  the  ear  ( incisura  aims),  situated  between  the 
helix  and  the  tragus. 

§ 1907.  The  lower  part  of  the  external  ear  or  the  lobule  ( auriculas , 
s.  lobulus  aurus ),  has  no  cartilaginous  frame.  It  is  only  a simple  pro- 
longation of  the  skin  filled  with  fat  and  mucous  tissue. 

The  cartilage  of  the  ear  extends  at  its  lower  part  into  a semicanal, 
which  is  open  above  and  is  termed  the  auditory  passage,  the  auricular 
or  oricular  channel  ( meatus  auditorius  cartilaginous).  This  canal  com- 
mences at  the  anterior  part  of  the  external  ear,  where  it  is  more  or  less 
covered  by  the  tragus  like  a valve.  Its  direction  is  at  first  transverse 
from  without  inward,  or  even  a little  from  below  upward  : it  then  be- 
comes in  most  of  its  course  oblique  from  below  upward  and  from  before 
backward.  It  is  terminated  above  by  the  long  posterior  root  of  the 
zygomatic  process  of  the  temporal  bone,  and  below  this  root  by  some 
fibrous  tissue. 

The  cartilage  of  the  auditory  passage,  which  is  only  a prolonga- 
tion of  that  of  the  ear,  is  generally  interrupted  in  some  portions  of  its 
extent. 


114 


DESCRIPTIVE  ANATOMY. 


The  principal  space  is  in  part  where  the  direction  of  the  passage  is 
changed  in  the  manner  mentioned.  There  in  fact  the  internal  and 
external  portions  of  its  cartilage  are  not  united  above  and  below  except 
by  a narrow  band. 

The  cartilage  also  presents  at  its  external  part  a second  smaller 
band,  which  descends  from  its  upper  edge  and  extends  along  its  an- 
terior wall. 

The  cartilaginous  auditory  passage  is  much  shorter  from  before 
backward,  than  from  above  downward.  It  is  about  an  inch  long,  four 
lines  high,  and  three  broad.  Its  inferior  part  extends  inward  and  down- 
ward some  lines  farther  than  the  upper. 

It  is  attached  to  the  adjacent  parts  of  the  temporal  bone  by  a firm, 
short  cellular  tissue.  Its  internal  orifice  particularly  unites  to  the  as- 
perities of  the  external  orifice  of  the  bony  portion  of  the  auditory  pas- 
sage, of  which  this  cartilaginous  portion  is  the  continuation. 

§ 1908.  The  cartilage  of  the  external  ear  is  entirely  covered  on  its 
external  and  its  internal  face  by  the  skin  which  intimately  adheres  to 
its  inequalities.  It  gradually  becomes  thinner  from  without  inward, 
moister  and  more  analogous  to  a mucous  membrane.  The  entrance 
of  the  auditory  passage  is  generally  furnished  with  short  thin  hairs 
which  are  arranged  very  compactly.  The  skin  which  lines  it  usu- 
ally presents  on  its  inner  face  a considerable  number  of  broad  rounded 
openings.  These  openings  lead  to  a glandular  and  reddish  layer, 
which  surrounds  them  and  secretes  the  wax  {cerumen  annum),  a thick 
yellowish,  viscous,  very  inflammable  fluid,  in  which  chemical  analysis 
demonstrates  a fatty  oil,  a peculiar  albuminous  and  a coloring  sub- 
stance.^) 

B.  MUSCLES  OF  THE  EXTERNAL  EAR. 

§ 1909.  The  cartilage  of  the  external  ear  is  provided  with  several 
muscles(2)  which  are  generally  thin  and  small,  and  may  be  referred 
to  two  classes  ; one  includes  those  which  move  the  whole  external  ear, 
and  thus  contribute  to  change  its  situation  and  direction  ; the  other 
is  composed  of  those  which  move  only  some  of  its  parts,  and  modify 
more  or  less  evidently  its  general  form. 

I.  MUSCLES  WHICH  MOVE  ALL  THE  EXTERNAL  EAR. 

§ 1910.  These  muscles  are  the  attollens  auricula , the  retrahentes 
auricula , and  the  attrahens  auricula. 

(1)  Berzelius  observes  ( Djurkmei , vol.  ii.  p.  230)  that  the  cerumen  ought  also  to 

contain  water,  and  it  is  not  well  proved  that  the  albuminous  substance  is  truly  of 
this  nature.  Rudolphi  considers  the  bitter  principle  of  the  cerumen  to  be  the  same  as 
that  of  the  bile.  F.  T. 

(2)  D.  Santorini,  Obs.  anat.,  cap.  i.  tab.  1 ; ejusdem  Tab.  posth.,  vol.  i. — A.  F. 
Walter,  Anatome  tenuiorum  musculorum  corporis  humani  repetita,  with  the  table  of 
Santorini. 


OP  THE  EAR. 


135 


a.  Attollens  auriculæ. 

§ 1911.  The  attollens  auriculae  muscle,  the  superior  auricular 
muscle,  temporo oriculaire,  Ch.,  the  largest  muscle  of  the  ear,  is  thin 
and  triangular.  It  arises  from  the  centre  of  the  aponeurotic  envelop  of 
the  skull  and  the  aponeurosis  of  the  temporalis  muscle,  contracts  from 
before  backward,  and  is  attached  to  the  eminence  of  the  auricular 
cartilage,  which  corresponds  to  the  triangular  depression  between  the 
two  branches  of  the  anthelix. 

It  elevates  the  ear,  particularly  during  the  action  of  the  occipito- 
frontalis muscle,  as  it  arises  from  the  median  tendon  of  this  muscle. 

b.  Retrahentes  auriculæ. 

§ 1912%  There  are  generally  three  retrahentes  auriculæ  or  posterior 
auricular  muscles,  mastoido-oriculaires , Ch.  Sometimes  there  are 
but  two,  more  rarely  four,  the  inferior  of  which  is  very  thin.  These 
muscles  are  always  situated  successively  from  above  downward,  are 
very  small,  thin,  and  elongated.  They  arise  from  the  mastoid  process, 
and  are  attached  by  short  tendinous  fibres  to  the  centre  of  the  external 
face  of  the  ear,  on  the  eminence  which  corresponds  to  the  entrance  of 
the  auditory  organ. 

Their  inferior  extremity  is  often  blended  with  the  occipitalis,  or  with 
the  complexus  or  the  sterno-cleido-mastoideus  muscles. 

These  muscles  draw  the  ear  backward,  and  slightly  dilate  the 
concha. 


c.  Attrahens  auriculæ. 

§ 1913.  The  attrahens  auriculæ  muscle,  the  anterior  auricular 
muscle,  zygomato-oriculaire,  Ch.,  is  also  very  small,  but  always  a 
little  larger  than  the  preceding.  It  arises  on  the  zygomatic  process, 
goes  backward  and  downward,  gradually  contracts,  and  is  attached  by 
a short  tendon  to  the  inferior  and  anterior  transverse  portion  of  the 
helix,  which  forms  the  commencement  of  this  eminence. 

It  carries  the  ear  forward  and  upward. 

II.  MUSCLES  WHICH  MOVE  CERTAIN  PARTS  OF  THE  EXTERNAL  EAR. 

§ 1914.  The  muscles  which  move  certain  parts  of  the  external  ear 
are  extremely  small  and  weak,  particularly  in  civilized  nations.  Being 
used  but  slightly  or  not  at  all,  they  cannot  modify  the  form  of  the  ex- 
ternal ear,  and  may  be  considered  as  rudiments  of  those  which  are 
much  more  developed  in  animals.  All  are  thin,  and  are  attached  by 
all  their  internal  face  to  the  part  of  the  ear  which  they  move. 

They  are  the  tragicus,  the  antitragicus , the  helicis  major , the  helicis 
minor,  and  the  transversus  auriculæ  muscles. 


116 


DESCRIPTIVE  ANATOMY. 


a.  Tragicus  muscle. 

§ 1915.  The  Iragicus  muscle,  tragien , Ch.  is  oblong.  It  arises 
from  the  inferior  and  anterior  part  of  the  concha,  directly  below  the 
tragus,  which  it  covers  outwardly.  Its  superior  edge  is  situated  below 
the  lower  extremity  of  this  eminence.  It  rarely  goes  farther,  and  ex- 
tends to  the  lower  extremity  of  the  anterior  edge  of  the  helix,  in  which 
case  it  is  even  blended  with  the  helicis  major  muscle. 

It  carries  the  tragus  outward,  and  thus  shows  the  orifice  of  the 

concha. 

b.  Anti-tragicus  muscle. 

§ 1916.  The  anti-tragicus  muscle,  antilragien,  Ch.  arises  from  the 
upper  extremity  of  the  external  face  of  the  antitragus,  and  is  attached 
to  the  lower  extremity  of  the  anthelix. 

It  approximates  these  two  eminences,  and  carries  the  anti-tragus  a 
little  backward  and  outward. 

c.  Helici3  major  muscle. 

§ 1917.  The  helieis  major  muscle,  grand  helicien,  Ch.,is  elongated. 
It  arises  from  the  inferior  extremity  of  the  helix,  and  ascends  on  the 
external  and  anterior  face  of  this  eminence,  to  which  it  is  attached  di- 
rectly above  the  point  where  the  ear  separates  from  the  head. 

It  draws  the  anterior  part  of  the  concha  a little  backward  and 
downward. 

d.  Helicis  minor  muscle. 

§ 1918.  The  helicis  minor  muscle,  petit  helicien,  Ch.,  is  the  smallest 
muscle  of  the  external  ear.  It  is  situated  like  the  preceding,  on  the 
external  face  of  the  helix  ; it  arises  much  lower  and  more  posteriorly 
than  it,  in  the  place  where  this  eminence  leaves  the  external  ear,  and 
is  attached  sometimes  higher  to  its  ascending  portion  near  the  pos- 
terior edge. 

It  slightly  depresses  the  anterior  part  of  the  helix. 

e.  Transversus  auricula:  muscle. 

§ 1919.  The  transversus  auriculae  muscle,  transverse  de  l'oricule, 
Ch.,  is  situated  on  the  internal  face  of  the  external  ear,  viz.  that  which 
looks  towards  the  head.  It  is  larger  than  the  preceding,  but  is  formed 
of  fasciculi  which  are  less  coherent,  and  generally  also  less  evidently 
fleshy.  Its  direction  is  transverse  in  almost  all  its  course,  and  it  ex- 
tends from  the  anthelix  to  the  scaphoid  fossa. 

It  draws  the  scaphoid  fossa  and  the  helix  outward,  and  thus  en- 
larges the  opening  of  the  ear. 


OF  THE  EAR. 


117 


ARTICLE  SECOND. 

INTERNAL  EAR. 

§ 1920.  The  internal  ear  ( auris  interna)(  1)  comprehends  : 

1st.  A considerable  portion  of  the  temporal  bone,  especially  the 
petrous  and  mastoid  processes. 

2d.  The  small  bones  of  the  ear,  which  moveably  articulate  with  the 
temporal  bone. 

3d.  The  muscles  which  move  these  little  bones. 

4th.  A cartilaginous  channel  by  which  the  ear  communicates  with 
the  cavity  of  the  mouth. 

5th.  A fibro-cartilaginous  expansion  contained  within  the  bony  por- 
tion of  the  ear. 

6th.  The  auditory  nerve  which  is  distributed  to  this  expansion. 

A.  EXTERNAL  PORTION. 

I.  OSSEOUS  PORTION  OP  THE  AUDITORY  PASSAGE. 

§ 1921.  The  osseous  portion  of  the  auditory  passage , conduit 
auriculaire , s.  oriculaire , Ch.  ( meatus  auditorius  osseus),  when  per- 
fectly developed,  forms  the  posterior  and  external  part  of  the  lower  face 
of  the  petrous  process  of  the  temporal  bone.  It  is  an  elliptical  canal, 
the  direction  of  which  is  from  above  downward,  from  behind  forward, 
and  from  without  inward,  which  gradually  contracts  in  the  same  di- 
rection. This  canal  is  about  half  an  inch  long.  Its  height  exceeds  its 
breadth. 

Its  external  orifice  which  presents  grooves  and  asperities  on  its 
edge,  is  called  the  external  auditory  foramen  ( porus  acusticus  externus, 
aditus  admeatum  auditorium  osseum).  It  is  turned  from  within  out- 
ward, and  is  intimately  united  to  the  cartilaginous  portion  of  the  audi- 
tory passage. 

Its  posterior  wall  is  a little  shorter  than  the  anterior.  It  is  lined  in 
its  whole  extent  by  a prolongation  of  the  skin  which  covers  ■ the  ear, 
and  which  gradually  becomes  thinner  from  without  inward. 

Its  internal  orifice  presents  a considerable  depression,  a groove  in 
which  the  membrane  of  the  tympanum  is  situated.  This  groove  ex- 
tends all  around  it,  except  its  upper  portion. 

(1)  C,  Folius,  Nova  auris  internee  delineatio,  Venice,  1645. — B.  S.  Albinus,  De 
aure  liumanâ  anteriore  ; in  the  Annot.  acad.,  book  iv.,  cap.  ii. — A.  Comparetti,  06- 
servationes  anatomicce  de  aure  interna  comparatâ,  Padua,  1789. — A.  Monro,  On  the 
brain,  the  eye  and  the  ear,  Edinburgh,  1797. — Ribes,  Mémoire  sur  quelques  parties 
de  V oreille  interne;  in  the  Bulletin  de  la  soc.  mêd.  d’émul.,  1823,  November,  p.  650 
December,  p.  707. 


Vol.  III. 


16 


118 


DESCRIPTIVE  ANATOMY. 


II.  MEMBRANE  OP  THE  TYMPANUM. 


§ 1922.  The  membrane  of  the  tympanum  (mem.  tympani),(l)  which 
is  inclosed  in  the  internal  orifice  of  the  auditory  passage,  separates  the 
canal  from  that  part  of  the  internal  ear  which  is  next  to  it,  that  is  from 
the  cavity  of  the  tympanum. 

It  is  a thin,  elliptical  membrane,  the  direction  of  which  is  a little 
oblique  from  above  downward,  from  without  inward,  and  from  behind 
forward.  There  is  positively  no  opening  in  it  in  the  normal  state, 
although  the  contrary  opinion  has  been  maintained  in  several  different 
forms.(2)  It  consequently  completely  separates  the  cavity  of  the  tym- 
panum and  the  labyrinth  from  the  osseous  portion  of  the  auditory 
passage  and  from  the  external  ear.  As  it  extends  a little  farther  than 
the  opening  which  receives  it,  its  form  changes  in  regard  to  its  degree 
of  tension  and  relaxa tion,(3)  which  is  produced  principally  by  the  ac- 
tion of  the  muscles  of  the  little  bones  of  the  ear.  It  fits  exactly  into 
the  groove  at  the  internal  extremity  of  the  auditory  passage. 

Anatomists  differ  in  opinion  in  regard  to  the  formation  of  the  mem- 
brane of  the  tympanum.  The  most  correct  consider  it  formed  of  a 
special  membrane  situated  in  the  centre,  of  a second  which  is  external, 
situated  next  to  that  of  the  bony  portion  of  the  auditory  passage. 
In  this  view  of  the  subject  the  external  layers  would  be  culs-de-sac  of 
the  internal  and  the  external  cutaneous  system,  while  the  middle 
layer  forms  a distinct  and  special  membrane  arising  from  the  bony 
portion  of  the  auditory  passage. 

This  special  membrane  presents  very  distinct  fibres  which  radiate 
from  its  centre  to  its  circumference,  and  are  very  manifest  in  its  internal 
face.  Judging  from  analogy,  that  is  from  what  occurs  in  the  large 
animals  particularly  the  elephant,  these  fibres  are  probably  muscu- 
lar. (4)  The  most  careful  injections  demonstrate  also  numerous  blood- 
vessels which  come  principally  from  two  circular  trunks,  an  external 
and  an  internal,  and  which  anastomose  together  frequently. 


(1)  A.  F.  Walther,  De  membrana  tympani,  Leipsic,  1725. — Brugnone,  Observa- 
tions anatomiques  sur  la  structure  de  la  membrane  du  tympan  et  de  celle  de  la  caisse  ; 
in  the  Mém.  de  Turin,  an.  xii.,  p.  1,(2. — E.  Home,  in  the  Phil,  trans.,  1804. 

(2)  Very  recently  even  Vest,  judging  from  his  own  observations  and  those  of 
Wittmann,  has  maintained  the  normal  existence  of  an  opening'  in  the  membrane  of 
the  tympanum,  admitted  some  time  since  by  Rivinus,  and  long  neglected.  He 
asserts  that  this  opening  is  oblique,  and  thus  forms  a kind  of  valve.  But  he  admits 
it  is  frequently  deficient  ( Uuber  die  Wittmann ’ sehe  Trommclfellklappe  ; in  the 
Medicinische  Jahrbücher  des  Oesterrenchischen  Staates,  vol.  v.,  Vienna,  1819,  p. 
123-133).  To  conclude  from  a few  cases,  which  were  probably  morbid,  that  the 
opening  is  formed  primitively,  is  evidently  to  make  the  exception  a rule.  F.  T. 

(3)  F.  Savart,  Recherches  sur  les  usages  de  la  membrane  du  tympan  et  de  l'oreille 
externe  ; in  the  Journal  de  physiol,  experiment.,  vol.  iv.,  p.  183. 

(4)  Sir  E.  Home  asserts  he  has  found  some  muscular  fibres  in  the  membrane  of  the 

tympanum  in  the  elephant.  Their  existence  is  at  least  doubtfnl.  Rudolphi  has 
observed  nothing  similar  in  the  whale  or  horse.  F.  T. 


OF  THE  EAR. 


119 


Of  the  two  superficial  layers  the  external  is  easily  insulated  : but  it 
is  more  difficult  to  separate  the  internal  from  the  middle,  both  on  ac- 
count of  its  fineness  and  because  it  adheres  to  this  latter  more  inti- 
mately. 

B.  MIDDLE  PART. 

X.  TYMPANUM. 

§ 1923.  The  tympanum  or  the  drum  ( tympanum , s.  cavitas  tym- 
pani){  1)  is  a narrow,  rounded  cavity,  which  is  generally  convex  inter- 
nally and  which  is  continuous  outwardly  with  the  osseous  portion  of 
the  auditory  passage  by  a broad  opening  before  which  the  membrane 
of  the  tympanum  is  expanded,  and  forward  with  the  Eustachian  tube 
through  another  narrower  opening.  This  cavity  forms  the  central 
part  of  the  internal  ear  ; hence  some  anatomists  term  it  the  middle  ear, 
in  opposition  to  the  labyrinth  and  all  the  parts  on  the  outside  of  it.  It 
occupies  the  external  and  posterior  part  of  the  petrous  portion  and 
communicates  anteriorly  with  the  cavity  of  the  mouth,  posteriorly  with 
the  mastoid  cellules. 

Its  internal  and  very  irregular  face  presents  numerous  elevations 
and  depressions  which  are  connected  with  the  labyrinth.  It  incloses 
the  little  bones  of  the  ear  and  the  cord  of  the  tympanum. 

When  we  consider  only  the  bones,  we  perceive  that  it  is  open  for- 
ward, backward,  and  downward.  A mucous  membrane  which  is 
continuous  with  that  of  the  throat  lines  its  whole  extent. 

§ 1924.  On  the  inner  face  of  the  cavity  of  the  tympanum,  forward 
and  downward,  at  about  its  centre  is  a considerable  eminence,  termed 
the  promontory  ( promontorium ),  formed  by  the  commencement  of  the 
cochlea,  and  always  covered  by  osseous  substance. 

At  its  lower  and  posterior  partis  an  oblong,  triangular  opening,  more 
high  than  broad,  which  is  directed  backward  and  outward  ; this  is  the 
fenestra  rotunda,  the  cochlear  opening  of  the  tympanum.{ 2)  This 
opening  communicates  with  the  cochlea,  but  it  is  closed  by  the  mu- 
cous membrane  which  lines  the  whole  cavity  of  the  tympanum. (3) 

Above  the  promontary  and  a little  above  the  centre  of  the  tympa- 
num is  a second  and  much  larger  opening,  called  the  fenestra  ovalis, 
the  vestibular  opening  of  the  tympanum  {fenestra  ovalis,  s.  semi-ovalis). 
The  length  of  this  opening,  the  greatest  diameter  of  which  is  directed 
from  above  downward  and  from  before  backward,  exceeds  its  breadth. 

(1)  Santorini,  Opp.  posth.,  tab.  v. 

(2)  A.  Scarpa  De  structurâ  fenestras,  rotnndœ  auris,  et  de  tympana  secundaria 
anatomicce  observations,  Modena,  1772. — Ribes,  loc.  cit.,  p.  652. 

(3)  Ribes  asserts  that  the  membrane  of  the  fenestra  rotunda  is  composed  of  a 

special  layer,  of  a second  given  off  by  that  of  the  cavity,  and  of  a third  coming  from 
that  which  lines  the  internal  scala  of  the  cochlea.  Its  structure  then  resembles  that 
of  the  membrane  of  the  tympanum.  F.  T. 


120 


DESCRIPTIVE  ANATOMY. 


Its  posterior  edge  is  convex,  the  anterior  is  straight.  It  is  surrounded 
outward  by  a small  groove. 

On  the  posterior  wall  of  the  cavity  of  the  tympanum  opposite  the 
lower  extremity  of  the  fenestra  ovalis,  farther  backward  and  much 
more  outward,  we  remark  the  pyramid  (emmentia  pyramidalis),  a small 
triangular  eminence  which  terminates  forward  by  an  opening  which  is 
grooved  in  it,  and  which  communicates  with  the  Fallopian  canal  : 
from  the  anterior  extremity  of  this  a small  bridge  of  bone  is  frequently 
detached,  which  goes  to  the  upper  extremity  of  the  promontory,  below 
the  fenestra  ovalis. 

Below  and  more  posteriorly  is  another  opening  ( apertara  chordœ) 
through  which  the  cord  of  the  tympanum  passes  from  the  Fallopian 
canal  to  the  tympanum. 

The  space  between  the  pyramid,  the  promontory,  and  the  fenestra 
ovalis  forms  a considerable  depression  termed  the  sinus  of  the  tympa- 
num ( sinus  tympani). 

Above  and  in  the  centre  the  cavity  of  the  tympanum  is  grooved  to 
receive  the  upper  part  of  the  two  largest  bones  of  the  ear. 

Upward  and  backward  it  communicates  by  one  or  more  considera- 
ble openings  with  the  cavity  of  the  mastoid  process,  which  must  con- 
sequently be  considered  as  a prolongation  of  it.  This  cavity  is  divided 
by  numerous  septa  into  cellules,  which  enlarge  much  from  the  centre 
to  the  circumference,  and  which  are  lined  by  the  mucous  membrane 
which  covers  the  inner  face  of  the  tympanum. 

The  internal  wall  of  the  tympanum  presents  at  its  anterior  part  a 
groove  which  leads  into  an  osseous  prolongation  ; this  extends  forward, 
and  is  the  bony  portion  of  the  Eustachian  tube  ( tuba  Eustachii  ossea). 
Above  this  groove  we  observe  a second,  which  sometimes  is  not  sepa- 
rated from  the  other  in  its  whole  extent,  and  which  lodges  the  tensor 
tympani  muscle. 

Under  the  posterior  extremity  of  the  second  groove  is  a small  open- 
ing which  leads  above  to  the  superficial  petrous  groove,  below  to  a 
groove  which  descends  on  the  promontory.  This  groove  becomes 
at  its  lower  part  a canal  which  opens  outward  on  the  lower  face  of 
the  pyramid,  between  the  carotid  canal  and  the  fissure  of  the  jugular 
vein. 

Through  this  canal  passes  a filament  of  anastomosis  between  the 
second  branch  of  the  trifacial,  the  glosso-pharyngceal,  and  the  gan- 
glionnary  nerve  ; this  minute  filament  arises  from  the  superficial 
petrous  nerve,  enters  the  cavity  of  the  tympanum  with  another  fila- 
ment of  the  great  sympathetic  nerve,  and  communicates  below  this 
cavity  with  the  ganglion  of  the  glosso-pharyngceal  nerve.(l) 


(1)  Jacobson,  Supplcmenla  ad  otoiatriam  ; in  Act.  IlaJ'n.,  vol.  v.,  1818,  p.  292. 


OP  THE  EAR, 


121 


II.  EUSTACHIAN  TUBE. 

§ 1925.  The  Eustach  an  tube , conduit  guttural  de  V oreille,  Ch, 
( tuba  Eustachii ),  is  a canal  the  posterior  part  of  which  is  formed  of 
bone,  but  is  fibrous  and  fibro-cartilaginous  at  its  anterior  portion,  and 
extends  from  the  tympanum  to  the  upper  part  of  the  pharynx.  The 
direction  of  this  canal  is  oblique  from  above  downward,  from  without 
inward,  and  from  behind  forward.  It  is  nearly  two  inches  long. 

The  osseous  portion  is  the  shortest,  and  is  situated  above  the  carotid 
canal.  It  becomes  narrow  from  behind  forward. 

The  cartilaginous  portion  proceeds  directly  below  the  base  of  the 
skull,  but  on  the  contrary  gradually  enlarges  in  the  same  direction. 
It  is  compressed  from  within  outward  in  its  wholq  extent.  Its  form  is 
elliptical  and  it  is  fibro-cartilaginous  in  the  inner  portion  and  sometimes 
also  in  the  upper  portion  of  its  external  wall.  In  other  parts  it  is  com- 
posed of  a fibrous  tissue  which  arises  from  the  periosteum  of  the  infe- 
rior pterygoid  process. 

The  Fallopian  tube  is  entirely  lined  internally  by  a very  fine  mucous 
membrane  which  is  continuous  with  that  of  the  oral  cavity  and  of  the 
tympanum.  Around  the  buccal  orifice  of  this  tube  this  membrane 
becomes  much  thicker,  partly  from  a great  development  of  the  muci- 
parous glands.  Thence  a prominence  is  formed  which  changes  this 
opening  into  a narrow  longitudinal  fissure  and  forms  a kind  of  valve. 


III.  BONES  OF  THE  EAR. 

§ 1926.  The  bones  of  the  ear  ( ossicida  auditus),{  1)  situated  at  the 
upper  part  of  the  cavity  of  the  tympanum,  are  the  smallest  bones  in 
the  body.  They  form  a chain  composed  of  pieces  movably  articu- 
lated with  each  other,  which  extends  from  the  membrane  of  the  tym- 
panum to  the  fenestra  ovalis,  consequently  to  the  labyrinth,  and  which 
conveys  to  the  deepest  parts  of  the  internal  ear  the  changes  which 
supervene  in  the  membrane  of  the  tympanum. 

There  are  three  bones,  the  hammer  {malleus),  the  anvil  {incus),  and 
the  stirrup  {stapes)  ; and  in  the  early  periods  of  life  a fourth,  the  lenti- 
cular bone. 


(1)  J.  A.  Schmid,  De  periostoo  ossiculorum  audilus  ejusque  vaseculis,  Leyden,  1719. 
— H.  F.  Teichmeycr,  Diss.  medica  solemnis  sistens  vindicias  quorundam  inventorum 
anatomicorum,  Leipsic,  1727.— Magendie,  Sur  tes  organes  qui  tendent  ou  relâchent 
la  membrane  du  tympan  et  la  chaîne  des  osselets  de  l'ouïe  dans  l’homme  et  dans  les 
animaux  mammifères  ; in  the  Jour,  de  phys.  expèrim..,  vol.  i.,  p.  341-347,  tab.  iv. 


122 


DESCRIPTIVE  ANATOMY- 


a.  Malleus. 

§ 1927.  The  hammer  ( malleus ) forms  the  anterior  and  external  part 
of  the  chain,  and  is  divided  into  a head , a neck,  a handle , and  pro- 
cesses. 

The  head,  the  upper  part,  is  rounded,  oblong,  convex  and  smooth 
forward,  concave  and  slightly  uneven  backward.  Its  posterior  face  is 
oblong  and  surrounded  by  a slightly  prominent  edge.  A transverse 
eminence  divides  it  into  an  upper  and  a lower  face. 

The  head  is  situated  above  the  inferior  edge  of  the  membrane  of  the 
tympanum  in  the  anterior  part  of  the  upper  prolongation  of  the  cavity 
of  the  tympanum. 

The  neck  is  short,  compressed  in  all  parts,  but  particularly  slightly 
flattened  from  without  inward. 

Its  lower  extremity  is  divided  into  three  sections,  the  handle  and  the 
two  processes. 

The  handle  ( manubrium ),  or  the  inferior  section,  descends  a little 
from  without  inward  and  from  behind  forward.  It  is  terminated  at  its 
lower  extremity  by  a small  prominence,  and  is  situated  between  the 
layers  of  the  membrane  of  the  tympanum. 

The  external  or  the  short  process  {processus  externus , s.  obtusus , s. 
brevis)  projects  more  or  less  at  the  upper  extremity  of  the  handle,  and 
forms  with  it.  a right  angle.  It  is  directed  outward,  and  is  separated 
by  a deep  groove  from  the  head,  into  which  the  upper  side  of  the  in- 
ternal extremity,  of  the  auditory  passage  enters. 

The  anterior  long  or  spinous  process  ( processus  anterior,  s.  longus, 
s.  spinosus ) is  thinner  but  much  longer  than  the  preceding,  and  is  con- 
vex above  and  concave  below.  It  is  received  by  a broad  and  super- 
ficial groove  hollowed  on  the  inner  face  of  the  upper  extremity  of  the 
ring  of  the  tympanum. 

The  malleus  is  connected  with  the  membrane  of  the  tympanum  and 
with  the  incus. 

b.  Incüs. 

§ 1928.  The  anvil  (incus)  has  nearly  the  form  of  a bicuspid  molar 
tooth  ; it  is  composed  of  two  branches  and  of  a centre  which  may  be 
termed  the  body.  , 

The  body  is  almost  square,  flat,  and  presents  forward  a concave  sur- 
face by  which  the  bone  articulates  with  the  head  of  the  malleus 
(§  1926).  It  is  situated  above  the  membrane  of  the  tympanum. 

The  upper  or  posterior  and  shorter  branch  is  flattened  from  within 
outward,  terminated  by  a blunt  summit  also  situated  above  the  mem- 
brane of  the  tympanum,  and  is  directed  horizontally  from  before  back- 
ward where  its  loose  extremity  terminates.  . 


OF  THE  EAR. 


123 


The  anterior  or  inferior  branch  varies  in  length  and  is  almost 
straight  ; its  direction  is  from  above  downward  and  from  behind  for- 
ward, and  it  is  situated  more  internally  than  the  preceding.  It  termi- 
nates in  a small  button-like  prominence  ; it  is  situated  behind  the 
handle  of  the  malleus,  a little  on  the  outside  of  it. 

The  body  of  the  incus  articulates  above  and  forward  with  the  head 
of  the  malleus,  by  its  long  branch  below  with  the  stapes.  It  is  not  di- 
rectly connected  with  the  membrane  of  the  tympanum. 

c.  Lenticular  bone. 

§ 1929.  The  lenticular  bone  - (os  lenticulare , s.  Sylvii)  is  an  ex- 
tremely small,  flat,  and  rounded  bone,  situated  on  the  inner  face  of  the 
lower  extremity  of  the  long  branch  of  the  incus.  It  generally  fuses 
with  the  incus  very  early,  even  during  the  latter  months  of  pregnancy, 
and  then  forms  an  eminence  which  projects  on  its  inner  face. 

d.  Stapes. 

§ 1930.  The  stirrup  ( stapes ) is  situated  more  internally  than  the 
other  two  bones  of  the  ear,  and  is  not  perpendicular  like  them  but  hori- 
zontal. It  is  composed  of  a head,  two  branches , and  the  transverse 
face  or  the  base. 

The  head  is  rounded,  oblong,  and  flattened  from  above  downward. 
Its  upper  extremity  looks  outward  and  presents  a slight  depression  for 
the  lenticular  bone  : the  two  branches  are  sometimes  separated  by  a 
contracted  neck. 

The  anterior  branch  is  always  shorter  and  also  straighter  than  the 
posterior  branch.  Both  are  grooved  on  their  internal  faces,  which  look 
towards  a groove  in  which  a membrane, ! a prolongation  of  that  of 
the  tympanum,  extends  between  them. 

The  base  has  exactly  the  same  form  as  the  fenestra  ovalis,  with 
which  it  is  movably  united  by  the  membrane  of  the  tympanum.  It 
is  always  a little  narrower,  so  that  it  can  enter  and  leave  the  vestibule 
through  this  opening. 

Its  inner  face,  which  corresponds  to  the  fenestra,  is  straight.  The 
external  is  concave  and  circumscribed  by  prominent  edges. 

IV.  MUSCLES  OF  THE  BONES  OF  THE  EAR. 

§ 1931.  The  small  bones  of  the  ear  are  moved  by  four  muscles, 
which,  like  the  bones  to  which  they  are  attached,  are  the  smallest  in 
the  body.  Three  of  these  are  inserted  in  the  malleus  and  one  in  the 
stapes.  Two  muscles. of  the  malleus  are  situated  before  the  cavity  of 
the  tympanum,  the  third  above  this  cavity.  That  of  the  stapes  is 
situated  behind  it.  The  incus  has  no  special  muscle  : it  forms  only  a 
connecting  link  between  the  malleus  and  the  stapes. 


124 


DESCRIPTIVE  ANATOM V. 


a.  Muscles  of  the  malleus. 

§ 1932.  The  three  muscles  of  the  malleus  from  their  connections  of 
the  bone  with  the  membrane  of  the  tympanum  vary  the  degree  of 
tension  of  this  membrane.  They  are  distinguished  into  an  internal  and 
an  external. 

1.  Tensor  tympani  muscle. 

§ 1933.  The  tensor  tympani  muscle,  the  internal  muscle  of  the  malleus 
{m.  tensor  tympani , s.  mallei  interims)  is  elongated.  It  arises  from  the 
upper  part  of  the  cartilaginous  portion  of  the  Eustachian  tube  near  the 
sphenoid  bone,  and  generally  comes  from  its  large  wing.  Its  direction  is 
from  before  backward  in  the  canal  from  which  the  petrous  process  is 
grooved  to  allow  it  to  pass  to  the  osseous  portion  of  the  tube.  In  the 
cavity  of  the  tympanum  the  direction  of  its  tendon  changes,  leaves  the 
internal  wall  of  this  cavity,  goes  outward  and  is  attached  to  the  upper 
extremity  of  the  inner  face  of  the  malleus  directly  below  its  long 
process. 

This  muscle  draws  the  malleus  inward,  tenses  the  membrane  of  the 
tympanum  which  the  bone  draws  with  it,  and  brings  the  chain  of  bones 
inward  so  as  to -sink  the  stapes  into  the  fenestra  ovalis. 

2.  Laxator  tympani  major  muscle. 

§ 1934.  The  laxator  tympani  major  muscle,  the  great  external 
muscle  of  the  malleus  (JVf.  laxator  tympani  major , s.  mallei  externus 
major),  arises  from  the  grooved  prolongation  of  the  great  wing  of  the 
sphenoid  bone,  and  is  directed  from  without  inward  and  from  before 
backward.  Its  tendon  enters  the  fissure  of  Glaser  and  is  attached  to 
the  long  process  of  the  malleus. 

It  draws  the  malleus  forward  and  outward,  and  thus  relaxes  the 
membrane  of  the  tympanum. 

3.  Laxator  tympani  minor  muscle. 

§ 1935.  The  laxator  tympani  minor  muscle,  the  small  external  mus- 
cle of  the  malleus  {JVL.  laxator  tympani  minor , s.  mallei  externus  minor) , 
is  much  smaller  than  the  two  preceding  and  arises  from  the  upper  edge 
of  the  osseous  portion  of  the  auditory  passage,  passes  between  the 
layers  of  the  membrane  of  the  tympanum,  goes  forward  and  outward, 
and  is  attached  sometimes  higher  and  sometimes  lower  to  the  handle 
and  the  external  process  of  the  malleus. 

It  draws  the  malleus  upward,  backward,  and  outward.  It  conse- 
quently relaxes  the  membrane  of  the  tympanum. 


OF  THE  EAR. 


123 


b.  Stapedius  muscle. 

§ 1936.  The  stapedius  muscie  (M.  stapedius)  is  oblong  and  trian- 
gular. It  arises  at  the  base  of  the  pyramid  and  goes  forward  and 
upward.  Its  tendon  comes  through  the  anterior  opening  in  the  top  of 
the  pyramid,  and  is  attached  to  the  posterior  part  of  the  head  of  the 
stapes. 

It  draws  the  stapes  backward  so  as  to  bring  the  posterior  portion 
of  its  base  into  the  fenestra  ovalis.  It  also  draws  the  chain  of  the 
bones  inward,  and  thus  tenses  the  membrane  of  the  tympanum. 

We  have  every  reason  to  think  that  it  acts  at  the  same  time  as  the 
tensor  tympani  muscle. 

C.  INTERNAL  PORTION  OR  LABYRINTH. 

§ 1937.  The  labyrinth  (labyrinthus),{  1)  the  most  internal  part  of 
the  organ  of  hearing,  comes  next  inside  to  the  tympanum.  It  is  a 
double  cavity  situated  in  the  petrous  portion  of  the  temporal  bone,  di- 
rectly surrounded  by  the  very  firm  substance  of  this  portion,  and  is 
formed  of  several  compartments  of  very  complex  figures.  We  distin- 
guish in  it  a central  part  the  vestibule , a posterior  part  the  semicircu- 
lar canals , an  anterior  portion  the  cochlea s and  the  lateral  parts  the 
aqueducts. 

One  of  the  two  cavities  which  form  it  completely  surrounds  the 
other  and  is  moulded  upon  it. 

The  first  is  the  osseous  labyrinth , the  second  the  membranous  laby- 
rinth. 


I.  OF  THE  OSSEOUS  LABYRINTH. 

§ 1938.  The  osseous  labyrinth  in  the  adult  is  not  distinct  from  the 
compact  substance  of  the  petrous  process  of  the  temporal  bone,  of 
which  it  forms  the  most  internal,  the  firmest  and  the  hardest  part, 
which  closely  envelops  and  covers  the  membranous  labyrinth.  But 
in  the  early  periods  of  life  it  is  formed  by  a solid,  hard,  and  brittle  sub- 
stance, separated  from  the  external  layer  of  the  petrous  process  by  a 
less  compact  osseous  tissue.  Its  internal  face  is  moistened  with  limpid 
serum  which  exactly  fills  all  the  space  between  it  and  the  membranous 
labyrinth.  (2) 

During  the  early  periods  of  life  we  find  between  the  two  labyrinths 
a membrane  which  is  not  the  periosteum  of  the  osseous  portion,  al- 
though generally  considered  as  such,  but  which  belongs  to  the  class 


(1)  A.  Scarpa,  Disquis.  anatomicæ  de  auditu  et  olfactu,  Pavia,  1789. — A.  Monro, 
lee.  cit. — Brugrone,  Observations  anatomico-physiologiques  sur  le  labyrinthe  de 
l’oreille  ; in  the  Mémoires  de  Turin , 1805-1808,  p.  167-177. 

(2)  Cotugno,  Diss.  cit.,  § xxix.— P.  F.  T.  Meckel,  De  labyrinthi  auris  cov.tev.tis, 
Strasburg,  1777. 

Vol.  III. 


17 


126 


DESCRIPTIVE  ANATOMY. 


of  sero-mucous  membranes.  This  is  demonstrated  by  the  numerous 
vessels  it  receives  and  by  its  abundant  secretion  and  its  connections 
with  the  membrane  of  the  tympanum. 

a.  Vestibule. 

§ 1939.  The  vestibule  ( vestibulum),(\ ) the  middle  of  the  bony  laby- 
rinth, is  situated  farther  inward  and  more  posteriorly  than  the  tym- 
panum. It  is  of  a rounded  and  oblong  cavity  at  about  the  centre  of 
which  we  perceive  the  internal  orifice  of  the  fenestra  ovalis.  We  there 
remark  principally  two  small  depressions  or  superficial  grooves,  one 
superior , posterior  and  external , more  extensive  than  the  other  and  of 
an  oval  form  (fovea,  s.  cavitas  ovalis,  s.  elliptica,  s.  semi- elliptic  a)  ; the 
other  inferior  and  anterior,  smaller  and  semicircular  ( fovea  hemi- 
sphœrica,  s.  orbicularis).  The  first  is  situated  on  the  posterior  and 
inferior  wall,  the  second  on  the  superior  and  external.  They  are 
separated  by  a sharp  crest  which  extends  from  above  downward. 

The  oval  fossa  kis  continuous  below  with  another  which  is  smaller, 
the  sulciform  groove  (fovea  sulciformis) . 

§ 1940.  In  the  circumference  of  the  vestibule  are  six  large  foramina 
and  one  which  is  rounded  and  very  small. 

Of  these  six  large  foramina,  one  which  occupies  the  anterior  and 
inferior  part  of  the  vestibule  leads  to  the  superior  scala  of  the 
cochlea  ; the  other  five  situated  at  the  posterior  part  are  the  orifices  of 
the  posterior  part  of  the  labyrinth  or  the  semicircular  canals. 

The  small  opening  at  the  posterior  and  inner  part  of  the  vestibule  in 
the  sulciform  groove  leads  to  the  aqueduct  of  the  vestibule. 

b.  Semicircular  canals. 

§1941.  'The  semicircular  canals  (canales  semi- circular  es)  form  the 
posterior  and  largest  part  of  the  labyrinth. 

There  are  three  of  them  which  occupy  a square  space  : the  superior 
or  anterior,  the  posterior , internal  or  inferior,  and  the  external.  The 
first  two  are  perpendicular,  the  third  is  horizontal. 

When  united  they  form  more  than  half  a semicircle.  They  are 
much  more  prominent  at  one  of  their  extremities  than  at  the  other  and 
in  the  rest  of  their  course,  so  that  they  represent  in  this  place  a rounded 
vesicle  (ampulla).  They  are  not  perfectly  round  externally  nor  intef- 
nally,  but  are  slightly  flattened  and  elliptical. 

The  diameter  of  their  cavity  is  about  half  a line. 

Their  orifices  are  a little  broader  than  the  rest  of  their  course. 

The  superior  is  oblique  from  without  inward  and  from  before  back- 
ward. It  forms  the  highest  part  of  the  labyrinth,  and  its  two  branches 
are  separated  the  farthest.  Its  anterior  and  external  opening,  which 


(1)  Ribes,  loc.  cit.,  p.  651. 


OF  THE  EAR. 


127 


is  situated  above  the  fenestra  ovalis,  forms  a considerable  vesicle  of 
which  we  see  another  trace  at  its  posterior  extremity,  through  which 
it  blends  with  the  superior  opening  of  the  internal  canal. 

The  inferior  is  also  perpendicular,  but  its  convexity  looks  backward 
and  its  concavity  forward.  It  commences  above  by  a short  canal 
which  it  has  in  common  with  the  internal  extremity  of  the  superior, 
and  terminates  by  a vesicular  enlargement  below  and  inward  in  the 
vestibule. 

It  is  the  longest  and  its  branches  are  nearest  each  other. 

The  external  or  horizontal  arises  by  a slightly  marked  vesicular 
prominence  below  the  external  orifice  of  the  superior.  Its  internal 
orifice  in  the  vestibule  is  situated  on  the  outside  and  below  the  com- 
mon opening  of  the  superior  and  the  inferior. 

It  is  the  shortest  and  also  the  broadest  of  the  three  semicircular 
canals. 

The  reunion  which  occurs  between  the  superior  and  inferior  canal 
diminishes  the  number  of  the  openings  of  the  semicircular  canals  to 
five  instead  of  six. 


c.  Cochlea. 

§ 1942.  The  cochlea(l)  forms  the  anterior  and  most  complex  part 
of  the  labyrinth.  It  presents  to  a certain  extent  the  repetition  of  the 
semicircular  canals,  and  its  figure  perfectly  resembles  that  of  the  shell- 
fish whose  name  it  bears. 

It  is  a grooved  canal  which  gradually  diminishes  from  its  origin  to 
its  extremity,  and  thus  it  finally  becomes  very  narrow.  It  turns 
around  a central  and  perpendicular  portion  termed  the  axis  (modiolus), 
which  gradually  becomes  thinner.  It  thus  describes  two  turns  and  a 
half. 

The  first  turn  is  much  larger  than  the  rest,  which  it  envelops  ; the 
others  however  project  much  beyond  it. 

§ 1943.  A horizontal  plate  of  bone,  which  arises  from  the  inner  part 
of  the  cochlea  and  which  is  termed  the  spiral  septum  ( lamina  spiralis ), 
divides  it  into  two  canals  situated  one  above  the  other  and  termed  the 
scalæ. 

The  lower  face  of  the  spiral  septum  presents  grooves  which  look 
towards  the  axis.  Its  upper  face  is  the  smoothest. 

It  is  formed  of  two  laminæ,  a superior  and  an  inferior. 

(1)  G.  Brendel,  De  auditu  in  apice  cochleae,  Program.  I.  II,  Gottingen,  1747. — J. 
G.  Zinn,  Observationes  de  vasis  subtilioribus  oculi  et  cochlea  auris  internee,  Got- 
tingen, 1753. — J.  G.  llg,  Einige  anatomische  Bemerkungen,  enthaltend  eine  Be- 
richtigung der  zeitigen  Lehre  vom  Bau  der  Schnecke  des  menschlichen  Gehöror- 
gans, nebst  einer  anatomischen  Beschreibung  und  Abbildung  eines  durch  ausseror- 
dentliche knochenwucherung  sehr  merkwürdigen  menschlichen  Schädels,  Prague, 


}28 


DESCRIPTIVE  ANATOMY. 


The  inferior  lamina  is  much  broader  than  the  superior,  and  termi- 
nates backward  and  outward  in  the  fenestra  rotunda  in  the  tympanum. 
This  has  been  termed  the  scala  of  the  tympanum  ( scala  tympani). 
It  is  separated  from  the  cavity  of  the  tympanum  by  a membrane  which 
presents  a depression  on  the  side  of  this  cavity  which  is  termed  the 
secondary  tympanum  ( tympanum  secundarium) . 

The  superior  scala  is  much  narrower  than  the  inferior.  It  terminates 
at  the  anterior  opening  of  the  vestibule.  Thence  it  is  termed  the  scala 
of  the  veslibide  ( scala  vestibuli). 

The  cochlea  however  does  not  continue  separated  the  entire  length 
of  this  cavity,  and  the  spiral  septum  terminates  near  the  middle  of  the 
second  turn  in  a pointed  hook  termed  the  hook  of  the  cochlea  ( hamulus 
cochleae). 

By  uniting  in  this  manner,  the  two  canals  of  the  cochlea  give  rise  to 
a tunnel-like  cavity,  the  infundibulum  ( scyplms ),  the  base  of  which  is 
turned  upward  and  the  summit  downward  towards  the  cupola  of  the 
cochlea. 

This  conical  cavity  forms  the  most  prominent  part  of  the  cochlea. 

The  axis(l)  which  turns  on  itself  is  hollow  like  the  scalæ.  A larger 
canal  passes  longitudinally  through  it  from  its  base  to  its  summit.  It 
also  presents  numerous  small  openings,  the  diameter  of  which  gradually 
diminishes  from  its  base  to  its  summit.  These  openings  lead  to  s>nal} 
canals  which  terminate  on  the  spinal  lamina. (2) 


(1)  Rosenthal,  Sur  la  structure  de  l'axe  du  limaçon  dans  l'oreille  de  l'homme  ; iji 
the  Journal  complém.  du  Diet,  des  sc.  méd ,,  vol.  xvi.,  p.  180. 

(2)  Anatomists  have  hitherto  considered  the  axis  of  the  cochlea  as  a small  column 
formed  by  a very  thin  osseous  lamina,  through  which  a canal  passes  from  the  base 
to  the  summit,  which  is  perforated  by  numerous  small  foramina.  It  is  asserted  that 
it  terminates  at  the  second  turn  of  the  cochlea,  at  the  top  of  which  it  appears  on 
leaving  this  place  as  a tunnel-form  layer  of  bone,  the  summit  of  which  is  the  termi- 
nation of  the  axis,  and  the  upper  extremity  of  which  looks  towards  the  summit  of 
the  cochlea  and  is  covered  by  a plate  of  bone.  Hence  are  distinguished  the  cavity  of 
the  axis  and  that  of  the  infundibulum.  There  is  also  admitted  in  the  latter  a thin 
column  around  which  the  spiral  septum  turns  from  the  second  curve,  and  which 
terminates  in  a small  osseous  plate  curved  like  a hook.  Ilg  describes  the  structure 
of  this  axis  differently.  He  states  that  the  spiral  channels  of  the  cochlea  do  not  turn 
around  a special  nucleus  of  hone;  hence  he  does  not  admit  an  axis,  but  asserts  that 
it  is  the  inner  and  concave  wall  of  the  spiral  canal  which  forms  the  species  of  column 
around  which  this  canal  turns,  and  that  we  perceive  in  it  the  form  of  a cylinder  on 
ppening  the  first  and  second  turn  of  the  cochlea.  The  column  is  very  thick  in  the 
first  turn  where  it  is  a line  and  a half  in  diameter,  but  very  thin  in  the'second  where 
its  diameter  does  not  exceed  half  a line.  As  the  internal  wall  of  the  spiral  canal 
forms  what  is  termed  the  a?is  in  the  first  two  curves,  so  likewise  if  produces  some- 
thing similar  in  the  third.  But.  this  pillar  of  the  third  turn  has  not  the  form  of  a 
cylinder  ; it  is  composed  only  of  a very  thin  and  twisted  osseous  plate,  which  arises 
from  the  summit  of  the  cylindrical  column  and  extends  to  the  cupola  of  the  cochlea, 
■where  it  is  attached.  The  loose  edge  of  this  plate,  which  exists  all  the  length  of  the 
imaginary  axis  of  the  cochlea,  from  the  termination  of  the  cylindrical  column  to  the 
top  of  this  cavity,  is  smooth,  rounded,  and  generally  a little  concave  in  the  direction 
of  its  length.  Sometimes  also  it  represents  a small  column  which  goes  directly  to 
the  summit  of  the  cochlea.  The  axis  of  the  column  is  perforated  by  a small  canal, 
and  this  column  is  filled  to  the  second  turn  by  an  osseous  cellular  mass,  the  cellules 
of  which  communicate  with  numerous  small  foramina  grooved  along  the  parietes  of 
the  column,  and  into  which  open  some  small  canals  which  proceed  between  the  two 
Jayerg  of  the  septum  or  spiral  lamina.  Rosenthal  has  since  modified  and  rectified  the 


OF  THE  EAR, 


129 


d.  Aqueducts. 

§ 1944.  The  aqueducts  ( aquceductus , diverticula, )(1)  of  the  laby- 
rinth are  short,  narrow  canals,  which  are  directed  from  above  down- 
ward through  the  substance  of  the  petrous  process  of  the  temporal 
bone,  and  which  enlarge  a little  in  their  course.  There  are  two,  the 
aqueduct  of  the  vestibule , and  the  aqueduct  of  the  cochlea. 

The  aqueduct  of  the  vestibule  ( aquceductus  vestibuli)  begins  by  a very 
small  opening  in  the  inner  wall  of  the  vestibule  before  the  common 
opening  of  the  two  perpendicular  semicircular  canals  in  the  sulciform 
groove  of  the  vestibule,  which  is  in  fact  their  internal  orifice.  It  first 
goes  a short  distance  from  without  inward  and  a little  from  below  up- 
ward in  the  centre  of  the  petrous  process,  then  from  above  downward, 
insensibly  enlarges  on  leaving  this  curve,  and  after  proceeding  about 
four  lines  terminates  a little  behind  the  centre  of  the  inner  face  of  the 
petrous  process  of  the  temporal  bone  near  the  fossa  intended  for  the 
gulf  of  the  internal  jugular  vein,  with  which  it  always  communicates 
by  a slight  groove. 

The  aqueduct  of  the  cochlea  ( aquceductus  cochlea ) commences  by  a 
wider  opening  in  the  tympanitic  scala  of  the  cochlea  directly  before 
the  fenestra  rotunda,  descends  from  before  backward,  enlarges  in  this 
course,  and  terminates  by  a triangular  opening  at  about  the  centre  of 
the  inferior  edge  of  the  petrous  process  of  the  temporal  bone. 

By  these  two  aqueducts  the  membranous  labyrinth  communicates 
externally, (2)  and  forms  culs-de-sac  between  the  bone  and  the  dura- 
mater. 

description  of  Ilg.  It  follows  from  his  researches,  that  from  the  summit  of  the  pillar 
of  the  first  two  turns  a layçr  proceeds  in  a semicircle  to  the  external  wall,  and  ter- 
minates by  a loose  and  semilunar  edge,  which  ascends  to  the  infundibulum.  The 
last  turn  is  open  on  the  side  of  this  edge,  by  which  the  lamina  turned  opposite  the 
pillar  terminates,  and  the  unciform  extremity  of  the  spiral  lamina  which  is  reflected 
around  tire  same  edge  projects  in  the  turn  in  question  ; the  two  laminpe  terminate  in 
this  place,  or  rather  blend  in  this  small  rounded  cavity.  The  crook  turning  around 
the  edge  of  the  lamina  of  the  axis  in  the  place  where  this  lamina  separates  from  the 
centre  of  the  pillar,  is  like  the  extremity  of  the  latter,  separated  from  the  infundi- 
bulum. The  edges  of  the  spiral  lamina  and  of  that  of  the  pillar  are  fitted  to  each 
other,  cross  so  that  their  faces  are  turned  from  the  side  of  the  external  wall  of  the 
cochlea,  and  as  the  latter  inclines  a little  towards  the  centre  of  the  pillar,  they  form 
in  some  measure  a broad  tunnel-like  edge  for  the  canal  grooved  in  the  first  two 
turns  of tfie  column  to  emerge.  It  follows  then  from  Rosent hal’s  description:  1st, 
that,  as  Scarpa  and  some  other  anatomists  have  asserted,  the  base  of  the  infundi- 
bulum is  situated  on  the  summit  of  the  cochlea  and  its  summit  in  that  of  the  pillar, 
but  it  does  not  extend  so  deeply  as  they  assert,  for  it  terminates  below  the  last  semi- 
turn and  is  loose  below  the  cupola  of  the  cochlea,  and  there  is  no  extended  lamina 
of  the  column  which  unites  with  its  covering  ; 2d,  that  Ilg  is  mistaken  in  saying 
that  the  axis  extends  to  the  centre  of  the  cochlea,  to  its  roof,  and  that  it  does  not 
form  a tunnel-like  edge,  and  is  attached  to  the  summit  of  the  cochlea  by  a rounded 
point  closed  at  its  extremity,  P.  T. 

(1)  D.  Cotugno,  De  aquæductibus  auris  humance  internee  anatomica  dissertatio, 
Naples,  1761. — P.  F.  Meckel,  De  labyrintJii  auris  contentis,  Strasburg,  1777.— -Ribes, 
loc.  cit,  p.  713. 

(2)  The  opinion  that  the  aqueducts  establish  the  communication  between  the  la- 
byrinth and  the  exterior  was  admitted  by  Cotugno,  who,  thinking1  that  the  internal 


130 


DESCRIPTIVE  ANATOMY. 


They  also  serve  for  the  passage  of  the  arteries  which  enter  the  laby- 
rinth and  the  veins  which  come  from  it  and  the  lymphatics,  the  ab- 
sorbent action  of  which  prevents  the  abnormal  accumulation  of  serum 
in  this  cavity.  The  veins,  and  perhaps  some  of  the  lymphatics  also, 
empty  into  the  internal  jugular  vein.  This  explains  why  mercury 
and  other  fluids  pass  from  the  labyrinth  into  this  vein  through  the 
aqueducts,  after  distending  the  sacs  of  the  membranous  labyrinth. 

ear  is  always  exactly  filled  with  scrum,  had  been  obliged  to  explain  how  this  liquid 
can  be  moved  by  the  compression  exercised  upon  it  by  the  base  of  the  stapes  to  sup- 
pose the  existence  of  derivative  canals,  which  allow  it  to  escape  in  part,  and  to  leave 
a certain  space  between  it  and  the  parietes  of  the  ventricle.  The  observations  of 
Brugnone  and  of  Ribes,  which  we  shall  mention  hereafter,  overturn  all  this  theory. 
These  anatomists  consider  the  pretended  aqueducts  only  as  passages  for  the  arteries 
and  veins.  In  regard  to  that  of  the  vestibule,  Ribes  has  discovered  that  at  about  the 
centre  of  the  posterior  face  of  the  petrous  portion  of  the  temporal  bone,  where  it 
begins  as  an  uneven  and  undulating  layer,  it  goes  forward,  upward,  and  outward, 
proceeds  first  on  the  inside  of  the  posterior  semicircular  canal,  next  between  the 
posterior  wall  of  the  vestibule  and  the  superior  semicircular  canal,  curves  and  pene- 
trates into  the  concavity  formed  by  this  canal,  thence  goes  backward  and  outward, 
and  is  distributed  in  the  spungy  tissue  of  the  posterior  part  of  the  labyrinth.  This 
duct  is  at  first  very  broad,  and  it  contracts  much  in  its  course  upward.  It  generally 
gives  off  in  its  course  other  smaller  duets,  at  each  of  which  it  becomes  smaller,  and 
among  which  Ribes  has  found  some  which  opened  into  the  inner  part  of  the  vesti- 
bule, others  into  the  posterior  semicircular  canal,  but  only  in  three  pieces,  for  in  all 
others  there  was  no  duct  from  the  aqueduct  proceeding  either  within  the  vestibule 
or  to  any  other  point  within  the  labyrinth.  Besides  this  aqueduct  does  not  exist  in 
the  full  grown  fetus  nor  even  some  time  after  birth.  It  is  designed  to  contain  the 
blood-vessels  which  ramify  in  all  the  spongy  tissue  surrounding  the  labyrinth,  and 
sometimes  enter  into  the  vestibule.  Ribes  asserts  that  the  aqueduct  of  the  cochlea 
arises  at  the  base  of  a small  depression  situated  about  the  centre  of  the  lower  edge 
of  the  petrous  portion  of  the  temporal  bone,  ascends  obliquely  to  the  lower  part  of 
the  internal  auditory  passage,  passes  under  the  labyrinth,  goes  horizontally  back- 
ward and  outward,  and  terminates  not  in  the  internal  scala  of  the  cochlea,  as  is 
stated,  but  in  the  canal  of  the  fenestra  rotunda  below  the  membrane  which  closes 
its  opening.  As  this  passage  proceeds  towards  the  tympanum  it  gives  rise  to  nu- 
merous branches.  It  lodges  the  vessels  which  are  distributed  under  the  labyrinth 
in  the  spungy  tissue  of  tne  petrous  portion  of  the  temporal  bone  and  within  the 
tympanum.  Thus  the  two  pretended  aqueducts  belong  to  the  class  of  vascular 
canals  described  in  a note  on  the  osseous  system.  But  there  are  others  beside  them 
observed  in  the  petrous  process.  Ribes  mentions  three  others-:  1st,  one  which  arises 
at  about  the  centre  of  the  posterior  base  of  the  petrous  process  near  its  upper  edge 
and  two  lines  from  the  internal  auditory  passage,  goes  backward  and  outward, 
passes  under  the  anterior  semicircular  canal,  opens  directly  under  the  curve  of  the 
superior  semicircular  canal,  where  it  receives  the  pretended  aqueduct  of  the  vesti- 
bule, with  which  it  then  goes  into  the  spungy  substance  of  the  posterior  part  of  the 
petrous  process  and  in  the  mastoid  cellules,  lined  by  a prolongation  of  the  dura- 
mater  : 2d,  another  which  arises  near  the  centre  of  the  anterior  face  near  the  upper 
edge  of  the  petrous  portion,  and  goes  behind  the  superior  semicircular  canal:  3d, 
another  which  arises  at  the  bottom  of  the  longitudinal  fissure  which  indicates  the 
union  of  the  petrous  process  with  the  squamous  portion  of  the  temporal  bone,  and 
through  which  pass  some  vessels  which  are  distributed  in  the  mastoid  cells  and  the 
membrane  of  the  tympanum.  These  details  may  seem  minute,  but  they  are  of  the 
highest  importance,  since  they  contribute  to  destroy  an  anatomical  error  on  which 
rests  a part  of  the  theory  by  which  physiologists  still  explain  the  philosophy  of  hear- 
ing. F-  T. 


OF  THE  EAR. 


131 


II.  MEMBRANOUS  LABYRINTH. 

§ 1945.  The  membranous  labyrinth(l)  is  inclosed  in  the  osseous 
labyrinth,  and  corresponds  perfectly  to  its  form,  although  it  is  much 
smaller. 

It  is  formed  of  a thin  and  whitish  membrane,  differing  entirely  from 
that  which  covers  the  inner  face  of  the  osseous  labyrinth  in  the  early 
periods  of  fetal  existence.  Its  external  face  adheres  to  the  inner  face 
of  the  bony  labyrinth  by  a loose  cellular  tissue.  It  contains  in  its  cavity 
a fluid  called  the  serum  of  the  membranous  labyrinth  or  the  lymph  of 
Cotugno , ( aquula  labyrinthi  membranacei)  .(2)  Numerous  vessels  are 
distributed  in  its  external  face. 

The  upper  and  posterior  part  of  the  osseous  vestibule  is  occupied  by 
a rounded  and  oblong  membranous  sac  in  which  the  membranous 
semicircular  canals  open,  which  enlarge  also  in  the  parts  which  cor- 
respond to  the  enlargements  of  the  osseous  canals.  Before  this  sac 
we  find  one  which  is  rounded,  perfectly  closed,  and  consequently  en- 
tirely separate  from  the  membranous  labyrinth,  which  is  smaller,  si- 
tuated partly  in  the  semicircular  fossa,  and  also  filled  with  a serous 
fluid.  These  two  sacs  are  attached  to  the  osseous  labyiinth  by  their 
posterior  wall.  The  anterior,  which  looks  toward  the  anterior  wall  of 
this  latter  and  the  fenestra  ovalis,  is  loose  and  surrounded  by  the  serum 
of  the  osseous  labyrinth.  The  semicircular  canals  are  arranged  pre- 
cisely like  the  osseous  semicircular  canals. 

The  membranous  cochlea  is  formed  by  a fibro-cartilaginous  layer, 
the  membranous  spiral  lamina,  which  is  adapted  to  the  external  and 
loose  edge  of  the  osseous  spiral  lamina,  and  which  becoming  softer 
and  thinner  on  the  outside  is  attached  by  its  external  edge  to  the  outer 
side  of  the  osseous  cochlea.  This  lamina  is  longer  than  the  osseous, 
for  it  extends  to  the  summit  of  the  cochlea..  In  this  part  of  its  course 
it  is  loose  on  its  inner  edge,  while  the  external  is  attached  as  in  every 
otljer  part.  It  terminates  in  a prominence. 

(1)  Scarpa,  loc.  cit. — Brugnone,  Observations  anatomico-physiologiques  sur  le  la- 
byrinthe de  l’oreille  ; in  the  Mémoires  de  Turin,  1805-1808,  p.  167-176. 

(2)  Ribes  {loc.  cit.,  p.  207)  remarks  that  there  are  many  adults  in  whom  this  hu- 

mor fills  the  labyrinth,  but  there  are  many  in  whom  it  is  partially  empty,  and  who 
nevertheless  always  hear  perfectly.  He  concludes,  from  these  remarks,  that  the 
labyrinth  is  not  constantly  filled  by  serum,  and  that  then  there  is  in  fact  a space 
doubtless  occupied  by  an  äeriform  fluid  ; but  this  space,  he  adds,  does  not  always 
exist  equally  in  all  the  cavities  of  the  labyrinth.  Sometimes,  in  fact,  we  find  little  of 
this  humor  in  the  semicircular  canals,  and  much  in  the  vestibule  and  the  cochlea  ; 
and  sometimes  the  semicircular  canals  are  full,  while  the  other  cavities  contain  but 
little.  Finally  he  thinks  that  these  changes  depend  only  on  the  situation  in  which 
the  cadaver  is  held.  These  observations  fully  confirm  those  of  Brugnone  ( Mém . 
de  Turin,  vol.  xvi.,  p.  167),  who  also  thinks  that  there  is  almost  always  serum  in  all 
the  cavities  of  the  labyrinth,  but  that  this  liquid  does  not  exactly  fill  them  in  the 
natural  state,  because  spaces  exist  in  ice  removed  from  them,  although  liquids  ac- 
quire more  volume  by  congelation.  F.  T. 


132 


DESCRIPTIVE  ANATOMY. 


III.  AVDITOBY  NEBVE. 

§ 1946.  We  have  already  mentioned  the  origin  of  the  auditory 
nerve  and  its  course  to  the  internal  auditory  passage,  accompanied  by 
the  facial  nerve.  On  entering  this  canal  the  auditory  nerve  divides 
into  several  branches,  -which  enter  the  labyrinth,  and  the  progress  of 
which  is  indicated  by  the  arrangement  of  the  bones. 

In  fact  the  internal  auditory  passage(l)  presents  at  the  base  of  its 
cavity  forward,  in  the  place  where  the  internal  and  perforated  plate  of 
the  axis  of  the  cochlea  is  situated,  a crest,  the  direction  of  which  is  from 
before  backward  ; it  is  at  first  slightly  sensible,  but  is  very  marked  in 
the  adult,  which  divides  it  into  two  halves,  a superior  and  an  inferior, 
which  is  larger.  The  first  belongs  entirely  to  the  facial  nerve,  while 
the  other  belongs  to  it  only  in  a small  portion  of  its  anterior  part,  so 
that  we  may  say  that  the  superior  groove  receives  the  facial  nerve,  and 
the  inferior  the  auditory  nerve.  The  first  is  divided  by  a longitudinal 
prominence  into  two  halves,  an  anterior,  the  commencement  of  the 
Fallopian  canal,  and  a posterior,  in  which  the  superior  branch  of  the 
auditory  nerve  is  situated. 

§ 1947.  The  auditory  nerve  is  distributed  to  the  membranous  laby- 
rinth.(2)  Its  first  branches  go  to  the  semicircular  canals  and  the  ves-^ 
tibule.  The  first,  the  largest,  passes  through  the  depression  behind 
the  origin  of  the  Fallopian  canal,  and  arrives  at  the  sac  of  the  superior 
semicircular  canal  ; the  second  goes  to  the  oval  depression  of  the  ves- 
tibule ; the  third,  still  smaller,  arrives  at  the  sac  of  the  posterior  semi- 
circular canal. 

When  the  first  branch  has  arrived  thus  far  it  divides  into  two  twigs, 
which  separate  like  a fan  ; one  of  them  goes  to  the  larger  or  common 
sac  of  the  semicircular  canals,  while  the  other  belongs  to  those  of  the 
superior  and  the  external  canal. 

All  these  twigs  are  evidently  fibrous  and  interlace  on  the  outer  face 
of  the  sacs,  but  when  examined  on  their  inner  face  they  appear  to  be 
a formless  mucus.  They  do  not  extend  over  the  whole  vestibule  and 
the  semicircular  canals,  but  remain  very  distinct  upon  the  surface  of 
the  sacs. 

The  nerve  then  goes  forward  in  the  axis  of  the  cochlea,  follows 
exactly  the  curves  of  the  cavity,  and  gives  off  numerous  filaments 
which  go  inward  through  the  openings  in  its  axis. 

The  first  filaments  given  off  are  the  largest  ; the  others  gradually 
diminish,  and  are  nearer  together. 

Finally  the  nerve  terminates  at  the  summit  of  the  axis  by  a consi- 
derable filament  much  larger  than  the  others,  and  which  enters  the 
openings  in  the  axis. 

(1)  Ribes,  loc.  cit.,  p.  660. 

(2)  Ribes,  ibid.  p.  665. 


OF  THE  EAR. 


133 


The  most  internal  of  these  filaments  pass  through  the  openings  in 
the  curves  of  the  pillar,  enter  into  the  canals  which  terminate  there, 
arrive  on  the  spiral  lamina,  form  an  extremely  minute  plexus  along  its 
two  faces,  and  terminate  on  the  membranous  spiral  lamina,  where  they 
are  entirely  exposed. 

Scarpa(l)  asserts  that  they  proceed  only  between  the  two  plates  of 
the  spiral  lamina  ; but  they  in  fact  cover  also  the  outside  of  the  supe- 
rior and  inferior  faces  of  this  Jayer,(2)  and  those  seen  in  this  place,  par- 
ticularly those  on  the  lower  face,  are  even  the  largest.  Some  fewer 
and  much  smaller  filaments  pass  through  the  foramina  in  the  spires  of 
the  cochlea  near  the  pillar,  and  go  not  into  the  spiral  lamina,  but  to 
that  portion  of  the  membranous  cochlea  which  forms  its  external  wall. 
All  anastomose  together  on  the  outside  of  the  cochlea. 

The  nervous  filaments  which  enter  the  cochlea  are,  like  the  prece- 
ding, white,  opaque,  and  evidently  fibrous  near  their  origin  ; but  their 
latter  expansions  are  semitransparent,  more  gray,  and  similar  to 
mucus. 

§ 1948.  The  changes  which  are  communicated  to  the  cerebrum  by 
the  auditory  nerve  and  excite  there  the  sensation  of  sounds,  take  place 
in  the  expansions  of  this  nerve  in  the  membranous  labyrinth.  These 
changes  are  doubtless  caused  by  the  compression  which  the  serum  in 
the  labyrinth  exercises  on  the  ramifications  of  the  nerves,  and  this 
pressure  is  necessarily  the  consequence  of  a change  in  the  state  of  the 
parts  on  the  outside  of  the  labyrinth,  especially  in  the  little  bones  of 
the  ear  and  their  muscles.  In  fact,  according  as  the  base  of  the 
stapes  is  more  or  less  deeply,  and  partially  or  wholly  imbedded  in 
the  fenestra  ovalis,  it  compresses  the  serum  within  it  in  different 
degrees,  and  presses  upon  different  parts  of  the  labyrinth.  The 
external  ear  and  the  membrane  of  the  tympanum  principally  serve  to 
receive  the  undulations  of  sound  and  to  strengthen  them,  which  is 
effected  by  the  tympanum  and  the  mastoid  cells.  In  regard  to  the 
little  bones  of  the  ear,  independent  of  the  use  assigned  them,  the  malleus 
certainly  modifies  the  degree  of  tension  of  the  membrane  of  the  tym- 
panum, serving  to  diminish  it  in  loud  and  to  increase  it  in  weak  sounds. 
The  Eustachian  tubes  serve  to  evacuate  the  fluids  secreted  In  the 
tympanum  and  to  admit  the  air,  to  balance  that  acting  on  the  out- 
side of  the  membrane  of  the  tympanum.  They  concur  also  directly  to 
healing,  for  they  also  lead  into  the  tympanum  the  undulations  of  sound, 
which,  reflected  by  the  w'alls  of  this  cavity,  fall  principally  on  the 
membrane  of  the  fenestra  rotunda,  called  for  this  reason  the  accessory 
tympanum. (3) 

(1)  De  org,  aud.  et  olf , p.  55-56,  § xi. 

(21  Monro,  On  the  ear,  p.  197-199,  vol.  iii-iv. 

(3)  Savart  has  concluded  from  his  important  researches  on  the  mechanism  of 
hearing  : 1st,  that  the  communication  of  the  vibrations  by  tire  air  seems  to  take 
place,  at  least  for  small  distances,  according  to  the  same  laws  as  those  for  solid  bo- 
dies; 2d,  that  it  is  not  necessary  lo  suppose  a special  mechanism  to  cause  the  mem- 
brane of  the  tympanum  to  vibrate  continually  in  unison  with  the  bodies  which  act 

Vol.  Ill,  18 


134 


DESCRIPTIVE  ANA  TOW  V 


ARTICLE  THIRD. 


DIFFERENCES  IN  THE  EAR  DEPENDENT  ON  DEVELOPMENT. 


I.  EXTERNAL  EAR. 

§ 1949.  The  external  part  of  the  organ  of  hearing  does  not  begin 
to  appear  till  towards  the  end  of  the  second  month  of  pregnancy.  It 
first  resembles  a slightly  perceptible  eminence  formed  like  an  elongated 
triangle,  the  base  of  which  looks  upward,  the  summit  downward,  and 
which  is  directly  continuous  with  the  lower  part  of  the  side  of  the 
head,  and  in  the  middle  of  which  is  a triangular  longitudinal  fissure 
which  becomes  narrower  and  deeper  from  above  downward.  The 
prominence  which  surrounds  the  median  depression  soon  rises  to  its 
posterior  part,  and  becomes  thinner  in  this  place.  It  projects  above  the 
surface  of  the  side  of  the  head,  and  slightly  shows  the  median  fossa. 
At  the  same  time,  or  soon  after,  the  anterior  part  of  the  prominence  is 
divided  by  a transverse  fissure  which  arises  from  its  posterior  part  into 
two  halves,  of  which  the  inferior  is  the  antitragus  and  the  superior  the 
commencement  of  the  helix.  At  the  same  time  this  anterior  part  of 
the  external  ear  also  rises  and  the  posterior  enlarges,  but  is  not  re- 

upon  it,  and  that  it  is  always  in  the  conditions  fit  to  be  influenced  by  any  number 
of  vibrations  ; 3d,  that  its  tension  probably  does  not  vary,  except  to  increase  or 
diminish  the  extent  of  these  variations,  as  Bichat  had  asserted,  but  always  supposing', 
as  Meckel  still  admits,  the  contrary  of  what  residts  from  these  experiments,  that  is, 
by  imagining  that  the  membrane  is  loose  in  loud  and  tense  in  feeble  sounds  ; 4tli, 
that  the  vibrations  of  the  membrane  extend  to  the  labyrinth  unchanged  by  means 
of  the  little  bones  ; 5th,  that  the  little  bones  also  serve  to  modify  the  extent 
of  the  vibrations  of  the  parts  in  the  labyrinth  ; Cth,  finally  that  the  tympanum  pro- 
bably serves  to  contain  an  air  the  physical  properties  of  which  are  constant.  Itard 
asserts  that  the  membrane  of  the  tympanum  does  not  perform  any  motion  which 
is  visible  or  denoted  by  a bristle  situated  in  the  centre  ; but  the  more  delicate 
experiments  of  Savart  do  not  allow  us  to  doubt  these  motions.  When  we  saw  the 
temporal  bone  on  the  level  of  the  external  face  of  the  membrane,  and  cover  this  with 
sand,  we  can  perceive  that  the  grains  move  slightly  when  we  bring  a disque  which 
is  vibrating,  parallel  to  the  membrane  and  near  the  surface,  although  its  slight  extent 
and  especially  its  form  do  not  allow  us  to  establish  there  any  nodal  line.  Itard 
states  that  the  function  of  the  little  bones,  are  to  allow  us  to  hear  low  tones.  J.  F.  St. 
Hilaire  thinks  that  they  arc  of  but  little  use,  and  are  only  indications  of  the  respira- 
tory apparatus,  the  operculum,  developed  in  fishes.  The  justice  of  this  second  pro- 
position, which  we  shall  not  examine  here,  would  not  necessarily  involve  that  of  the 
first,  although  not  contradicted  by  experience.  The  direct  participation  of  the 
Eustachian  tube  in  hearing,  which  was  asserted  in  the  commencement  of  the  last 
century,  and  afterwards  brought  forward  by  Brcssa,  is  evidently  erroneous.  It  has 
been  perfectly  refuted  by  Cotugno  and  Itard.  If  it  was  correct,  we  ought,  as  Ru- 
dolphi  asserts,  hear  our  own  voice  when  speaking  loudly  after  stopping  the  ears  : 
hut  this  is  not  true.  Itard  has  very  ingeniously  compared  the  Eustachian  tube  to  a 
hole  without  which  the  air  in  a military  drum  would  not  vibrate  ; but  he  is  mistaken 
in  saying  that  it  seems  only  to  renew  the  air  in  the  tympanum.  This  is  undoubtedly 
its  principal  function,  but  it  also  serves  to  excrete  the1  mucus  and  the  condensed 
perspirat  ion  constantly  secreted  by  the  mucous  membrane  of  this  cavity.  F.  T, 


OF  THE  EAR 


135 


moved  farther  from  the  side  of  the  head.  The  anthelix  and  the  tragus 
are  developed  also  very  early  at  the  third  month.  The  anthelix  is  at 
first  more  prominent  than  it  is  subsequently,  because  the  posterior 
edge  of  the  ear  rises  but  slightly  or  not  at  all.  The  lobule  appears 
last. 

The  external  ear  is  much  smaller  in  proportion  to  the  head,  the 
younger  the  fetus  is. 

Its  cartilage  begins  to  appear  at  the  third  month  ; but  it  is  deve- 
loped slowly,  for  towards  the  end  of  pregnancy  it  is  not  as  yet  so 
extensive  under  the  skin  as  in  full  grown  individuals. 

The  cartilaginous  portion  of  the  auditory  passage,  like  the  external 
ear,  is  at  first  proportionally  much  smaller  than  subsequently. 

The  long  portion  of  this  passage  begins  to  form  some  time  after  birth 
by  the  enlargement  of  the  cavity  of  the  tympanum.  Its  ossification  is 
singular  in  this  respect,  that  it  generally  begins  much  sooner  in  the 
external  part  of  the  canal,  where  it  unites  to  the  cartilaginous  portion, 
than  in  the  middle  region  of  its  lower  part. 

The  prolongation  of  the  external  cutaneous  system,  around  which 
this  passage  is  situated,  already  exists  very  early  in  the  fetus,  and 
it  is'  not  then  even  proportionally  much  shorter  than  in  the  adult, 
but  it  has  another  form  and  another  direction.  As  the  direction  of  the 
tympanum  is  then  much  more  oblique  from  without  inward  than  it 
is  afterward,  the  upper  part  of  its  circumference  at  first  does  not 
exist  ; the  inferior  alone  is  developed,  and  forms  on  the  outside  and  at 
the  bottom  of  the  tympanum,  a large  sac,  which  is  much  more  ample 
in  proportion  to  its  length  than  it  is  afterward,  descends  also  more  per- 
pendicularly, and  is  situated  below  the  membrane  of  the  tympanum, 
so  as  really  to  form  its  upper  wall. 

The  skin  of  the  bony  portion  of  the  auditory  passage  is  softer  and 
thicker  in  the  fetus  than  in  the  adult. 


§ 1950.  1st.  The  tympanum  in  the  early  periods  of  life  is  proportion- 
ally shorter  and  narrower  than  at  a later  season,  particularly,  because 
the  mastoid  process  is  very  small,  and  its  cells  are  not  yet  formed.  It  is 
filled  in  the  fetus  with  a thick  gelatinous  fluid,  and  it  communicates 
with  the  mouth  more  directly  the  younger  the  fetus  is,  since  the 
Eustachian  tube  is  shorter  and  broader  in  the  same  proportion.  The 
cartilaginous  portion  of  this  tube,  until  the  middle  of  pregnancy,  is 
simply  membranous,  and  even  in  the  full  grown  fetus  the  bony  portion 
is  at  most  separated  within  the  canal  by  a layer  of  bone,  which  forma- 
tion continues  most  generally  through  life,  so  that  the  septum  rarely 
extends  also  to  the  outer  side. 

The  tympanum,  and  with  it  the  membrane,  are  much  larger  in  pro- 
portion either  to  the  external  ear  or  to  the  whole  head  and  body,  the 
younger  the  fetus  is,  and  even  until  the  fifth  month  of  pregnancy,  both 


II.  INTERNAL  EAR, 


130 


DESCRIPTIVE  ANATOMY. 


arc  larger  than  the  external  ear.  Besides,  as  the  osseous  portion  of 
the  auditory  passage  is  not  yet  developed,  the  membrane  of  the  tym- 
panum is  much  nearer  the  surface  in  the  early  periods  of  existence 
than  subsequently,  so  that  the  upper  part  directly  touches  the  entrance 
of  the  cartilaginous  portion  of  the  auditory  passage,  and  consequently 
is  almost  exposed  in  this  point,  a very  curious  circumstance  from  its  ana- 
logy with  reptiles.  Both  also  differ  at  first  in  direction,  which  is  more 
horizontal,  because  at  this  period  the  membrane  of  the  tympanum  is 
more  oblique  from  above  downward  and  from  without  inward. 

2d.  The  small  bones  of  the  ear  differ  from  all  other  bones  of  the  body 
by  their  uncommonly  early  appearance  and  development. 

They  are  visible  and  even  uncommonly  large  in  proportion,  at  the 
commencement  of  the  third  month  of  pregnancy,  although  at  this 
period  they  are  still  entirely  cartilaginous,  and  we  cannot  well  dis- 
tinguish the  stapes  from  the  incus.  Thus,  for  instance,  the  malleus  is 
about  three  lines  high  in  the  fetus  of  four  months,  so  that  the  body 
being  then  four  inches  from  the  vertex  to  the  coccyx,  its  length 
is  to  that  of  the  whole  body  as  1 : 16,  while  in  the  adult,  where  is  to 
four  lines  long,  and  where  the  distance  between  the  vertex  and  the 
coccyx  is  two  feet  and  a half,  the  proportion  is  only  as  1 : 90.  The 
small  bones  of  the  ear  are  as  large  in  the  full  grown  fetus  as  in  the 
adult. 

They  begin  to  ossify  also  very  early,  even  before  the  end  of  the  third 
month.  Cassebohm  asserts(l)  that  the  stapes  and  incus  ossify  sooner 
than  the  malleus,  that  the  osseous  nucleus  of  the  incus  is  seen  first  in 
its  anterior  branch,  and  that  of  the  stapes  in  the  head,  whence  it  ex- 
tends along  the  two  branches  to  the  base,  which,  with  the  lower  region 
of  the  anterior  branch,  ossifies  the  last.  In  the  malleus,  ossification 
commences  in  the  head  and  anterior  process.  Our  observations  do  not 
exactly  agree  with  those  of  Cassebohm.  It  is  true  that  the  anterior 
branch  of  the  incus  ossifies  before  the  posterior  : we  have  always  found 
it  perfectly  ossified,  while  the  latter  was  entirely  cartilaginous,  but  the 
ossification  of  the  malleus  commences  at  the  same  time  as  that  of  the 
incus,  and  the  stapes  is  still  entirely  cartilaginous,  when  it  has  ad- 
vanced considerably  in  the  other  two  bones.  The  place  where  it  be- 
gins in  the  stapes  is  not  well  determined  : it  is  sometimes  in  the  lower 
part  of  the  posterior  branch,  and  sometimes  in  the  base,  but  never,  ac- 
cording to  our  observations,  in  the  head. 

These  bones  differ  very  much  in  their  forms.  The  incus  changes 
the  least.  The  branches  of  the  stapes  seem  at  first  not  to  be  separated 
from  each  other,  which  deserves  to  be  noticed  on  account  of  the  ana- 
logy resulting  from  it  with  the  formation  of  this  bone  in  the  cetaceous 
animals,  and  with  that  of  the  inner  part  of  the  single  bone  of  the  ear 
in  birds  and  reptiles.  It  is  certain  that  even  where  these  two  branches 
are  detached  from  each  other,  the  opening  between  them  and  the  base 
is  proportionally  much  smaller  than  at  subsequent  periods,  although, 


(1)  Loc.  ci t.,  p.  56. 


OF  THE  EAR. 


137 


however,  its  form  is  then  less  oblong.  This  narrowness  of  the  fora- 
men, which  is  evidently  an  approximation  to  its  entire  deficiency,  and 
the  union  of  all  the  parts  of  the  stapes  in  one,  depend  principally  on 
the  greater  thickness  of  its  branches. 

But  of  all  the  bones  of  the  ear,  the  malleus  changes  the  most  during 
its  development.  Perhaps  no  other  bone  can  be  compared  with  it  in 
this  respect. 

The  most  remarkable  difference  is  the  existence  of  a right  cartila- 
ginous process,  formed  like  a very  elongated  cone,  which  is  also  very 
long  and  very  thick  in  proportion  to  the  rest  of  the  bone.  This  pro- 
cess arises  from  the  anterior  side  of  its  head,  leaves  the  tympanum 
between  the  petrous  process  of  the  temporal  bone  and  the  ring  of  the 
tympanum,  is  fitted  directly  to  the  inner  face  of  the  lower  jaw,  and 
extends  to  the  anterior  extremity  of  this  bone,  where  it  sometimes, 
perhaps  even  always,  unites  with  that  of  the  opposite  side.  This 
cartilage  never  ossifies,  although  in  the  commencement  it  forms  most 
of  the  mass  of  the  bone  ; it  disappears  at  the  eighth  month.  The  an- 
terior process  of  the  malleus  corresponds  with  it,  it  is  true,  to  a certain 
extent,  in  respect  to  its  position  : but  we  also  perceive  that  in  the  fetus, 
where  the  two  parts  are  distinct  from  each  other,  the  cartilage  is  situ- 
ated above  the  anterior  process.  We  may  then  at  most  admit  that  this 
latter  makes  part  of  it,  and  that  they  are  separated  very  early.  This 
cartilage  is  very  curious,  because  fishes,  reptiles,  and  birds,  present  a 
similar  one,  which  extends  from  the  posterior  to  the  anterior  portion  of 
the  lower  jaw.  In  these  animals  it  rests  on  a small  bone  placed  on 
the  inner  face  of  the  posterior  part  of  the  lower  maxillary  bone,  and  we 
may  consider  it  as  a rudiment  of  the  malleus,  which  does  not  exist  in 
them. 

3d.  The  membranous  labyrinth  exists  long  before  the  osseous 
labyrinth.  We  have  found  it  at  three  months  perfectly  developed  in 
the  cartilaginous  mass,  which  afterwards  ossifies.  Even  in  the  early 
periods  of  life  it  is  more  distinct,  and  formed  of  firmer  and  more  solid 
membranes  than  at  subsequent  periods.  It  is  composed  at  first  of  two 
very  distinct  membranes,  an  external  and  an  internal,  which  are 
simply  inclosed  in  each  other,  but  there  is  no  continuity  between 
them. 

The  internal  is  white,  transparent,  thinner,  but  firmer  and  more 
elastic  than  the  external.  The  latter  does  not  adhere  to  the  cartilage, 
as  afterward  it  is  not  attached  to  the  bone  which  is  developed  at  the 
expense  of  this  latter. 

The  inner  face  of  the  external  membrane  is  smooth,  and  the  external 
is  corrugated.  It  gradually  disappears,  so  that  at  seven  months  we 
cannot  trace  it.  Before  entirely  disappearing  it  gradually  becomes 
thinner.  The  internal  becomes  proportionally  narrower  but  firmer  : it 
seems  to  be  attached  more  intimately  to  the  inner  face  of  the  cartilage 
which  surrounds  it,  in  the  early  periods  of  existence  than  subse- 
quently. 


138 


DESCRIPTIVE  ANATOMY. 


As  yet  we  have  been  unable  to  ascertain  if  there  is  not  a period 
when  the  membranous  labyrinth  is  uncovered  in  the  skull,  at  least  in 
part,  and  where  its  structure  is  more  simple  than  it  is  afterward.  At 
three  months  it  is  entirely  surrounded  by  a mass  of  cartilage,  and  is  as 
complex  in  its  structure  as  at  a more  advanced  period  of  life.  We  only 
remark,  that  like  the  cartilage  which  envelops  it,  it  is  at  first  more 
compressed  from  without  inward,  and  proportionally  higher,  which  un- 
doubtedly depends,  at  least  in  part,  on  the  greater  development  of  the 
encephalon. 

At  four  months  we  find  the  membranous  cochlea  as  complex  as  it  is 
in  the  adult,  while  afterward  its  circumference  seems  to  be  formed  only 
by  the  membranous  labyrinth;  it  is  then  constituted  by  a very  thick 
membrane,  which  makes  a part  of  this  latter.  We  have  as  yet  been 
unable  to  obtain  any  sufficient  data  in  regard  to  its  form  before  the 
fourth  month  of  pregnancy. 

The  secondary  tympanum  and  the  finestra  rotunda  are  at  first 
situated  more  externally  and  parallel  to  the  membrane  of  the  tympa- 
num. They  afterwards  go  backward,  which  depends  principally  on 
the  development  of  bone  in  their  circumference. 

4th.  When  we  study  the  development  of  the  osseous  labyrinth,  we 
must  distinguish  the  formation  of  the  osseous  substance  of  the  petrous 
process  of  the  temporal  bone  from  that  of  its  own.  The  first  commen- 
ces before  the  second,  and  follows  the  usual  mode  of  ossification, 
that  is,  it  takes  place  by  the  development  of  a loose,  soft,  and  plexi- 
form tissue,  in  the  homogeneous  mass  of  cartilage  previously  existing, 
which  gradually  extends  from  before  backward.  The  circumference  of 
the  fenestra  rotunda  ossifies  first  towards  the  end  of  the  third  month, 
which  is  curious  as  an  analogy  between  this  opening  and  the  tympa- 
num. Ossification  begins  at  the  upper  part,  then  extends  to  the  lower, 
and  when  it  has  thus  formed  a ring,  it  goes  forward.  At  the  same 
time  there  is  developed  a special  osseous  nucleus,  which  is  entirely 
distinct  from  the  preceding,  at  the  outer  extremity  of  the  superior  per- 
pendicular semicanal  : next  there  appears  a third  small  scale  at  about 
the  centre  of  the  internal  perpendicular  semicanal.  At  the  same  time 
ossification  proceeds  rapidly  backward  and  downward  from  the  point 
first  formed,  and  gives  rise  to  the  floor  of  the  labyrinth.  The  second 
nucleus  enlarges  more  quickly  perhaps  than  the  first,  so  that  the  su- 
perior perpendicular  semicanal  is  soon  entirely  ossified,  excepting  only 
its  lower  and  concave  face.  At  the  same  time,  ossification,  commencing 
at  its  internal  extremity,  advances  on  the  internal  face  of  the  petrous' 
process,  circumscribes  the  internal  auditory  foramen,  enters  within  it, 
and  forms  the  floor  of  the  cochlea. 

The  horizontal  semicircular  canal  begins  to  ossify  at  the  fifth  month. 
At  this  time  the  piece  of  bone  which  forms  the  superior  perpendicular 
canal  extends  backward,  downward,  and  outward,  around  the  mem- 
branous horizontal  canal.  At  least  we  have  been  unable  to  discover 
a special  nucleus  for  this  canal,  which  seems  to  ossify  by  the  extension 
of  the  first  two  nuclei,  the  edges  of  which  finally  unite. 


OF  THE  EAR. 


139 


The  formation  of  the  interior  of  the  cochlea  belongs  almost  wholly 
to  the  osseous  labyrinth.  The  cartilage  and  then  the  osseous  sub- 
stance of  the  petrous  process,  do  not  participate  in  it  except  by  a nar- 
row prolongation  sent  by  this  latter  into  the  cavity  containing  the 
membranous  and  then  the  osseous  labyrinth,  the  spires  of  winch  it 
slightly  separates. 

The  loose  edge  of  this  projecting  lamina  is  turned  outward.  It  ex- 
tends from  the  upper  part  of  the  fenestra  rotunda  and  the  outside  of  the 
cochlea,  to  the  summit  of  this  latter,  across  its  cavities,  and  thus  divides 
it  anteriorly,  but  very  imperfectly,  into  an  external  and  an  internal 
cavity.  This  lamina  is  broader  at  first  than  it  is  subsequently.  Be- 
sides, the  internal  face  of  the  cochlea  is  entirely  smooth,  and  this  part 
of  the  internal  ear  presents  at  this  period  the  greatest  analogy  with  the 
cochlea  of  birds  : at  a later  period,  after  the  third  month,  as  the  cochlea 
enlarges  from  without  inward,  the  lamina  in  question  becomes  nar- 
rower, and  at  the  same  time  slight  prominences  are  developed,  which 
separate  externally  the  two  and  half  turn's  of  the  cochlea  from  each 
other,  and  make  part  of  it. 

The  osseous  labyrinth  is  at  first  entirely  separated  from  the  osseous 
mass  of  the  petrous  process  which  surrounds  it,  and  which  is  developed 
before  it.  It  is,  however,  always  applied  to  it.  Its  surface  then  is  en- 
tirely smooth.  The  inner  face  of  the  osseous  mass  of  the  petrous  pro- 
cess is  also  smooth  to  a certain  extent,  although  more  corrugated  than 
that  of  the  labyrinth.  The  two  surfaces  soon  blend  together,  but  they 
can  be  entirely  separated  in  children,  and  the  smooth  polished  surface 
of  the  labyrinth  can  be  demonstrated  ; but  they  afterward  become  in- 
separable. The  line  of  demarkation  is  very  evident  in  every  part, 
particularly  in  the  cochlea,  where  it  is  perceived  that  the  prolongations 
described  above  are  perfectly  distinct  from  the  canal  formed  by  the 
membranous  and  osseous  labyrinths. 

Thus  the  osseous  labyrinth  is  developed  independent  of  the  osseous 
substance  of  the  petrous  portion.  As  the  external  membrane  of  the 
membranous  labyrinth  disappears  at  the  period  of  its  formation,  it  is 
not  improbable  that  it  changes  into  osseous  substance,  or  at  least  that 
this  substance  transudes  through  its  external  face.  In  fact,  this 
membrane  does  not  exist  for  some  time  with  the  osseous  labyrinth,  and 
may  always  be  easily  separated  from  it  : but  we  are  satisfied,  from  nu- 
merous observations,  that  as  the  osseous  labyrinth  is  developed  around 
it,  it  becomes  denser,  firmer,  dryer,  and  in  a measure  horny  : hence  we 
have  been  induced  to  believe  that  the  two  modes  of  formation  coexist, 
that  is,  that  the  membrane  secretes  first  the  labyrinth,  then  that  an 
analogous  substance  being  deposited  with  it,  it  unites  with  the  layer  it 
had  first  formed,  and  becomes  its  internal  layer.  The  formation  of  the 
osseous  labyrinth  would  thus  resemble  that  of  the  teeth.(l) 

(1)  Ribes  has  asserted  that  in  the  fetus  the  serum  of  the  labyrinth  is  reddish, 
bloody,  and  exactly  fills  it.  As  the  infant  grows  older,  it  becomes  clear,  limpid,  and 
less  in  quantity,  and  the  ear  becomes  more  sensible  to  sounds.  F.  T. 


140 


DESCRIPTIVE  ANAl'OlVtY. 


ARTICLE  FOURTH. 

ORGAN  OF  HEARING  IN  THE' ABNORMAL  STATE. 

§ 1951.  As  the  organ  of  hearing  is  very  complex,  it  presents  very 
numerous  and  very  different  anomalies(l)  in  respect  to  their  essence  ; 
by  these  the  ear  is  unusually  hard  or  soft,  or  is  entirely  deficient. 

§ 1952.  The  deviations  of  formation  are  here,  as  in  every  other  part, 
the  most  interesting  in  a physiological  point  of  view. 

As  in  all  other  parts  of  the  body,  they  are  more  or  less  characterized 
by  a retarded  development, (2)  and  are  also  more  or  less  repetitions  of 
what  is  observed  in  animals  inferior  to  man. 

Sometimes  the  development  of  the  whole  car  is  arrested. (3) 

I.  EXTERNAL  EAR. 

§ 1953.  1st.  Deviations  of  form  in  regard  to  quantity.  The  entire 
absence  of  the  external  ear,  of  which  we  possess  some  instances,  de- 
pends on  the  permanence  of  a state  which  marks  the  early  periods 
of  fetal  existence. 

The  anomaly  varies  a little  less  from  perfect  development  when  the 
ear  is  closed,  which  can  exist  in  different  degrees;  these  lead  imper- 
ceptibly to  the  normal  formation  by  the  shortness  and  narrowness  of 
the  external  auditory  passage. 

The  absence  of  the  lobule,  or  its  adhesion  with  the  skin  of  the  head, 
is  the  least  deviation  from  the  normal  state.  This  state  also  exists 
regularly  at  a certain  period  of  the  formation  of  the  fetus. 

We  may  consider  the  frequent  enormous  enlargement  of  the  ears  as 
an  anomaly  of  an  entirely  different  character. 

2d.  Deviations  of  formation  in  regard  to  quality.  These  are  the 
turning  of  the  ear  on  the  orifice  of  the  external  auditory  passage, 
which  more  or  less  closes  this  canal.  (4) 

II.  INTERNAL  EAR. 

A.  TYMPANUM. 

§ 1954.  1st.  Deviations  of  formation  in  respect  to  quantity.  Some- 
times the  tympanum  is  not- sufficiently  large,  and  is  even  closed  on  the 

(1  ) Besides  the  works  of  Duvernoy,  Wildberg-,  and  Saunders,  already  mentioned, 
which  treat  also  of  the  diseases  of  the  ear,  consult,  J.  A Rivinus,  De  auditvs  ritiis , 
Leipsic,  1717.— J.  M.  G.  Itard,  Traite  des  maladies  de  l’oreille  et  de  l'audition, 
Paris,  1821. — C.  F'.  A.  Escbke,  Diss.  de  avditusvitiis,  Berlin,  1819. 

(2)  See  on  this  subject  our  Handbuch  der  jiathologischcn  Anatomie,  vol.  i.  p. 
400-406. 

(3)  Rœderer,  Descripl.  fœtus parasiU;  in  Comm.  soc.  Gostl.,  vol.  iv. 

(4)  Walter,  PeUhaulgeschwüLslc , Land  shut,  1814.  p.  33. 


OF  THE  EAR. 


141 


outside  as  in  fishes.  Sometimes  one  or  more  of  the  little  bones  of  the 
ear  are  deficient,  or  they  are  too  small. (1)  Sometimes  they  are  un- 
usually large,  thus  preserving  the  distinctive  characters  of  the  fetus. 
They  are  rarely  more  numerous  than  usual.  When  supernumerary 
bones  exist,  they  are  always  very  small.  They  occur  particularly  be- 
tween the  malleus  and  incus,  and  also  in  the  neck  of  the  stapes. 

2d.  Deviations  of  formation  in  regard  to  quality.  The  bones  of  the 
ear  are  sometimes  formed  after  a different  type,  and  then  are  more  or 
less  similar  to  those  of  certain  animals. 

Thus  Comparetti(2)  observed  in  a man,  that  not  only  the  two 
stapedes  were  very  small,  but  also  formed  by  a single  branch,  with  a 
small  base  closing  the  fenestra  ovalis,  which  was  very  narrow. (3) 


B.  LABYRINTH. 

When  the  labyrinth  is  very  imperfectly  developed,  there  is  only  a 
single  cavity  closed  externally,  which  is  not  divided  into  the  vestibule, 
cochlea,  and  semicircular  canals,  and  which  does  not  communicate 
with  the  tympanum. (4)  This  form  resembles  that  of  the  organ  of 
hearing  in  the  Crustacea  and  the  cephalopoda.  Perhaps  it  is  normal 
also  in  the  early  periods  of  the  existence  of  the  human  fetus. 

When  the  development  is  more  advanced,  the  cochlea  describes 
fewer  turns  than  usual, (5)  even  as  in  reptiles  and  birds,  it  appears  as 
a sac-like  prolongation,  which  is  not  curved  on  itself.  From  our  pre- 
ceding remarks,  this  anomaly  should  be  considered  as  a continuance 
in  the  fetal  state. 

The  labyrinth  is  sometimes  ossified  imperfectly,  whence  a portion  of 
the  membranous  labyrinth  is  exposed.(6) 

(1)  Bernard,  Sur  un  vice  d'organisation  de  l’oreille  externe;  in  the  Journ.  de 
physiol,  expér.,  vol.  iv.  p.  167. 

(2)  Loc.  cit.,  p.  24. 

(3)  Wefind  the  malleus  sometimes  larger,  sometimes  shorter,  sometimes  with  an 

enlarged  head  or  process.  The  incus  has  been  observed  sometimes  narrower,  some- 
times broader,  and  sometimes  with  its  long  branch  more  or  less  arched.  Rudolphi 
has  described  and  figured  (Diss.  sis.  observationes  osleologicas,  Berlin,  1812,  tab.  i. 
fig.  15.)  a stapes,  of  which  the  branch  alone  communicated  with  the  base,  the  other 
being  loose,  and  forming  with  the  preceding  an  obtuse  angle.  Lœsecke  seems  to 
have  observed  a similar  case  ( Obs . anat.  Chirurg.,  Berlin,  1754,  p.  15.)  Tiedemann 
has  described  a stapes  found  in  a newly  born  infant,  which  presented  neither 
branches  nor  opening.  It  resembled  a small  pyramid,  the  base  of  which  represented 
the  plane  surface,  and  from  whence  a piece  of  bone  arose,  slightly  depressed,  which 
was  articulated  with  the  long-  branch  of  the  incus  by  a rounded  process.  He  has  also 
seen  in  an  adult  the  two  branches  of  the  stapes  completely  united  by  a layer  of  bone, 
so  that  there  is  a slight  depression,  but  no  opening  between  them  ( Sur  quelques 
variations  dans  la  forme  de  l’etricr  chez  l’homme  ; in  the  Journ.  complém.  des  sc. 
méd.,  vol.  viii.  p.  83.  F.  T. 

(4)  Roderer,  loc.  cit.— Meckel,  Handbuch  der  pathologischen  Anatomie , vol.  i.  p. 

(5)  Mondini,  Anat.  surdinati;  in  the  Comm.  Bonon.,  vol.  viii.— Meckel,  loc.  cit. 

vol.  i.  p.  403.  ’ ’ 

(6)  Mondini,  loc.  cit. 

Vol.  III. 


19 


142 


DESCRIPTIVE  ANATOMY. 


C.  AUDITORY  NERVE. 

Sometimes  in  deaf  and  dumb  people  the  auditory  nerve  is  smaller(l) 
by  half  than  it  is  generally. (2) 

§ 1955.  The  accidental  or  consecutive  deviations  of  formation  result 
from  an  external  lesion,  which  is  purely  mechanical,  or  an  alteration  in 
texture.  Sometimes  in  hydrocephalus  the  two  external  bones  of  the 
ear  are  pushed  outward  and  detached  from  the  stapes,  and  sometimes 
even  this  is  unconnected  with  the  fenestra  ovalis.(3) 

§ 1956.  The  alterations  of  texture  in  the  organ  of  hearing  are  prin- 
cipally inflammation  and  its  consequences,  among  which  we  must  first 
mention  adhesion  and  suppuration,  which  frequently  affect  the  ex- 
ternal and  the  internal  ear.  The  buccal  orifice  of  the  Eustachian 
tube  is  frequently  obliterated  after  scarlatina,  or  the  tympanum 
and  the  bones  are  destroyed  by  ulceration.  The  entire  or  partial  de- 
struction of  the  membrane  of  the  tympanum  and  very  probably  also 
the  anomalies  in  the  tumors  of  the  labyrinth,  which  are  thickened, (4) 
solidified,  and  changed  into  a hard  body  (5)  after  long  affections  of  the 
internal  ear, (6)  belong  to  this  class. 

The  new  formations  developed  in  the  organ  of  hearing  are  : 

1st.  Accidental  ossification , by  which  the  bones  of  the  ear  adhere  to 
each  other,  and  obstruct  the  fenestra  rotunda, (7)  in  which  case  we  also 
find  the  bones,  particularly  the  stapes,  twice  as  large  as  they  are  gene- 
rally : the  stapes  also  is  fused  with  the  fenestra  ovalis,(8)  and  forms 
osseous  concretions(9)  in  the  membrane  of  the  tympanum. (10) 

(1)  Haighton,  Mem.  of  the  med.  society, x ol.  iii.  p.  1. 

(2)  This  fact  has  been  observed  several  times,  among1 2 3 4 * 6 7 8 9 10  others  by  Sylvius,  Hoffman, 
and  Arenda.  Itard  also  has  seen  it:  but  he  thinks  that  the  wasting  of  the  auditory 
nerve  is  more  frequently  the  effect  than  the  cause  of  deafness  (toc.  cit.,  vol.  i.  p.  392.) 

F.  T. 

(3)  Blumenbach,  Geschichte  der  Knochen,  p.  140. 

(4)  Haighton,  toc.  cit. — Cline,  in  Saunders,  toc.  cit.,  p.  88. 

(5  ) Seeon  this  subject  an  important  memoir  on  the  physiological  relations,  by  G. 
F.  St.  Hilaire,  Sur  la  nature,  la  formation  et  les  usages  des  pierres  qu'on  trouve 
dans  les  cellules  auditives  des  poissons  ; in  the  Mém.  du  Muséum,  1824. 

(6)  Itard  has  seen  one  case  ( loc . cit.,  vol.  i,  p.  395)  where  the  fluid  of  the  labyrinth 
was  deficient. 

(7)  Cotugno,  loc.  cit.,  § 72,  p.  61. 

(8)  Valsalva,  De  mire  humanâ , cap.  ii.  § x. 

(9)  Cassebohm,  vol.  iii.,  p.  33. — Loesecke,  Ohs.  anal.,  p.  25. — Koehler,  Beschrei- 
bung der  Loderischen  Präparate,  p.  148. 

(10)  Kibes  (loc.  cit.,  p.  654)  has  found  the  membrane  of  the  fenestra  rotunda  ossified 
in  a man  completely  deaf,  and  destroyed  in  several  subjects,  some  of  whom  had  not 
completely  lost  the  power  of  hearing.  This  latter  circumstance  deserves  to  be  re- 
marked, since  complete  deafness  does  not  result  from  injuries  of  the  membrane  of 
the  tympanum,  which  is  so  analogous  to  that  of  the  fenestra  rotunda.  According 
to  Pinel’s  observations,  it  would  seem  that  deafness  depends  on  an  alteration  in  the 
texture  of  the  mucous  membrane  of  the  internal  ear  rather  than  on  any  other  cause, 
although  he  seems  to  attribute  it  to  the  diminution  of  the  fluid  in  the  labyrinth, 
which  in  this  case  is  only  a consequence  of  inflammation.  (Recherches  sur  tes 
causes  de  la  surdité  chez  les  viellards  ; in  the  Archiv,  gén.  de  méd.,  vol.  vi.,  p.  247.) 


OF  THE  EYE. 


143 


2d.  The  formation  of  accidental  cartilages  and  fibro-cartilages  some- 
times observed  under  the  form  of  tumors  which  adhere  to  the  auditory 
nerve.(l) 

Among  the  entirely  abnormal  formations  we  must  arrange  the 
fungous  tumors  and  the  polypi , which  are  developed  principally  in  the 
mucous  membrane  of  the  auditory  passage. 


CHAPTER  II. 


ORGAN  OP  SIGHT. 

§ 1957.  The  organ  of  sight  ( oculus)(2 ) occupies  the  upper  part  of 
the  front  of  the  face,  and  is  situated  on  the  right  and  left,  on  the  sides 
and  above  the  root  of  the  nose  in  the  orbit  and  circumference  of  this 
cavity.  We  distinguish  the  eye  or  the  globeof  the  eye  ( bulhus  oculi) 
with  the  muscles  which  move  it  and  the  parts  which  protect  it. 


ARTICLE  FIRST. 

PARTS  WHICH  PROTECT  THE  EYE. 

§ 1958.  The  parts  which  protect  the  eye(3)  comprise  two  folds  of 
skin,  called  the  eyelids , very  thick  hairs,  called  the  eyebroivs , and  the 
lachrymal  passages. 


(1)  Sandifort,  Obs.  anat.  pathol.,  book  i.  c.  9. 

(2)  Fabricius  d’Aquapendente,  De  visione,  voce  et  auditu , Venice,  1606. — V.  F. 
Plemp,  Ophthalmographia , s.  tractatio  de  oculo,  Louvain,  1648. — G.  Briggs,  Oph- 
thalmographia, seu  oculi  ejusque  partium  descriptio  anatomica,  London,  1685. — J. 
Taylor,  Nouveau  traité  d’anatomie  du  globe  de  l'œil , avec  l’usage  de  ses  différentes 
parties , et  de  celles  qui  lui  sont  contiguës , Paris,  1738. — A.  Bertrandi,  Diss.  II.  de 
hepate  et  oculo , Turin,  1748'. — J.  G.  Zinn,  Descriptio  anatomica  oculi  liumani , Got- 
tingen, 1753. — G.  Porterfield,  Treatise  on  the  eyes , the  manner  and  phenomena  of 
vision , F.dinburgb,  1759. — M.  Horrebow,  De  oculo  humano  ejusque  morbis , Copen- 
hagen, 1792. — A.  Monro,  Miscellaneous  observations  on  the  structure  and  the  func- 
tion of  the  eyes  ; in  his  Treatise  on  the  brain,  the  eye , and  the  ear,  Edinburgh,  1797. 
— S.  T.  Sœmmerring,  in  Demours,  Traité  des  maladies  des  yeux,  vol.  iv. — J.  G. 
G.  Voit,  Oculi  humani  anaiomia  et  pathologia,  Nuremberg,  1810. — C.  H.  T.  Schre- 
ger,  Versuch  einer  vergleichenden  Anatomie  des  Auges,  Leipsic,  1818. — D.  G.  Sœm- 
merring, De  oculorum  humani  animaliumque  sectione  horizontali,  Gottingen,  1818. 
— J.  A.  Hegar,  Diss.  de  oculi  partibus  quibusdam,  Gottingen,  1818. — C.  F.  Simon- 
son,  Anatomico-physiologicus  tractatus  de  oculo,  Copenhagen,  1820. 

(3)  Rosenmuller,  Organorum  lacrymalium  partiumque  oculi  externarum  descriptio, 
Leipsic,  1797. 


144 


DESCRIPTIVE  ANATOMY. 


I.  EYELIDS. 

§ 1959  The  eyelids  (palpebrœ)  are  perpendicular  folds  situated 
before  the  anterior  orifice  of  the  orbit,  which  they  close  more  or  less 
perfectly.  They  are  distinguished  into  upper  and  lower.  They  blend 
together  in  the  great  or  internal  angle,  and  the  small  or  external  angle 
of  the  eye  ( cantlii  oculi , intermis  et  cxiernus ),  and  are  separated  from 
each  other  their  entire  breadth  by  a transverse  fissure  ( fissura  palpe- 
brarum). 

The  superior  is  much  greater  than  the  inferior  ; a flat  ligament 
formed  of  transverse  fibres  several  lines  long,  leaves  the  great  angle  of 
the  eye  and  goes  inward  between  the  fibres  of  the  internal  portion  of 
the  orbicularis  palpebrarum  muscle  ; its  internal  extremity  is  broader 
than  the  external,  and  is  attached  to  the  upper  part  of  the  nasal  pro- 
cess of  the  superior  maxillary  bone.  This  is  the  palpebral  ligament 
( lig . palpebrarum). 

The  eyelids  are  composed  of  two  layers  of  skin,  one  external  and  the 
other  internal,  of  cartilage  and  muscular  fibres.  They  rarely  or  never 
contain  fat. 

The  exterior  layer  of  skin  makes  a part  of  the  external  cutaneous 
system.  It  differs  from  the  rest  of  the  skin  only  in  being  very  thin  and 
destitute  of  hair. 

It  is  continuous  on  the  edge  of  the  eyelids,  which  is  nearly  a line 
broad,  with  the  internal  layer  which  belongs  to  the  internal  cutaneous 
system,  that  is,  to  the  mucous  membranes.  This  layer  is  also  thin, 
reddish,  and  moist. 

It  is  termed  the  conjunctiva.  It  lines  the  whole  extent  of  the  inner 
face  of  the  eyelids,  is  reflected  on  itself  in  the  parts  where  these  movable 
folds  are  attached  to  the  rest  of  the  skin,  and  is  called  the  tunica  ad- 
nata, is  fitted  to  the  anterior  part  of  the  sclerotica , from  which  it  may 
always  be  easily  separated,  and  which  it  covers  to  the  circumference 
of  the  transparent  cornea.  At  least  it  is  not  possible  strictly  to  demon- 
strate that  it  extends  also  on  the  anterior  face  of  this  last  membrane, 
for  if  in  certain  morbid  affections  a layer  rises  on  the  anterior  face  of 
of  the  cornea,  this  circumstance  authorizes  us  to  think,  but  does  not 
prove,  that  this  layer  in  question  is  a prolongation  of  the  conjunctiva. 
Admitting  that  this  passes  really  on  the  cornea,  and  that  it  blends  with 
the  external  pellicle  of  this  membrane  without  any  marks  of  separa- 
tion, it  does  not  follow  that  it  possesses  in  this  place  the  characters  of  a 
serous  membrane,(l)  for  the  anterior  face  of  the  transparent  cornea 
belongs  rather  to  the  class  of  the  mucous  membranes. (2)  Walther  has 
already  demonstrated(3)  that  it  is  wrong  to  exclude  the  conjunctiva 

(1)  P.  P.  Walther,  Abhandlungen  aus  dem  Gebiete  der  pralclischcn  Med.,  Land- 
shut,  1810,  p.  413. 

(2)  Wardrop,  Morbid  anatomy  of  the  eye,  Edinburgh,  1818,  p 14. 

(3)  Loc.  cit.,  p.  414. 


OF  THE  EYE. 


145 


entirely  from  among  the  last  membranes.  The  adhesions(l)  between 
its  two  opposite  faces  which  have  been  brought  forward  to  sepa- 
rate it  from  the  other  mucous  membranes,  and  which  have  been  used 
to  a certain  extent  to  class  it  among  the  serous  membranes,  are  rare 
and  accidental,  and  supervene  probably  after  suppuration,  in  which 
case  even  the  mucous  membranes  contract  adhesions. 

A.  EYELASHES. 

§ 1960.  The  anterior  part  of  the  edges  of  the  eyelids  presents  three 
or  four  irregular  ranges  of  short,  straight  and  arched  hairs,  which  gra- 
dually become  larger  from  the  two  angles  of  the  eye  to  the  centre,  and 
which  are  termed  the  eyelashes  (cilia). (2)  Those  of  the  upper  lid  are 
more  numerous  and  stronger  than  those  of  the  lower.  The  former 
are  arched  from  above  downward,  the  latter  from  below  upward. 
When  the  lids  close  they  intercross  and  form  from  their  curve  a broad 
ridge. 

B.  MEIBOMIAN  GLANDS. 

& 

§ 1961.  Farther  back  and  nearer  the  posterior  limit  of  the  edge  of 
the  eyelids,  at  about  its  centre,  is  a series  of  openings  regularly  arranged, 
which  are  also  larger  in  the  upper  than  in  the  lower  eyelid,  and 
which  do  not  occupy  the  entire  breadth  of  these  movable  lids.  These 
openings  lead  to  the  glands  of  JMeibomius,  or  the  sebaceous  glands  of 
the  eyelids  (Gl.  JWeibomiance , s.  'palpebrarum  sebaceœ),  small,  very 
elongated,  narrow,  tortuous  bursæ,  which  terminate  in  sacs  generally 
single,  but  sometimes  divided  at  their  base  into  several  compartments, 
which  are  situated  perpendicularly  below  the  conjunctiva,  between  it 
and  the  tarsaL  cartilages.  These  glands  are  filled  with  a thick,  yel- 
lowish -viscous  substance,  called  lema,  which  accumulates  around  the 
eyelashes  during  sleep,  and  which  is  easily  distinguished  by  its  color 
from  the  red  conjunctiva. 


C.  PALPEBRAL  CARTILAGES. 

§ 1962.  Each  eyelid  contains  between  the  two  layers  of  skin  and 
near  its  loose  edge  an  oblong  cartilage,  called  the  tarsus , which  de- 
termines its  form.  These  cartilages  extend  much  farther  from  without 
inward  than  from  above  downward,  and  they  are  very  thin  from  before 
backward.  They  are  much  thicker  at  their  loose  and  straight  edge 
than  on  their  convex  portion,  which  looks  to  the  base  of  the  eyelids  ; 

(1)  A.  Schmidt,  in  the  Ophthalmologische  Bibliothek.,  vol.  iii.,  part  1,  p.  18. 

(2)  H.  Meibom,  De  vasis  palpebrarum  novis  Epist.,  Helmstadt,  1666. 


146 


DESCRIPTIVE  ANATOMY. 


they  extend  on  the  inside  only  to  the  lachrymal  puncta,  and  terminate 
on  the  outside  also  a little  before  the  commissure  of  the  two  eyelids. 
Their  convex  edge  and  their  internal  and  external  extremity  becomes 
at  the  two  angles  of  the  eye  a very  dense  cellular  tissue,  which  is 
called  the  tarsal  ligament  ( lig . tarsi , internum  et  externum ) ; this  unites 
them  to  the  external  and  internal  edge  of  the  anterior  opening  of  the 
orbit. 


D.  MUSCLES  OP  THE  EYELIDS. 

§ 1963.  The  eyelids  have  two  muscles  which  act  in  opposite  di- 
rections, the  orbicularis  'palpebrarum  and  the  levator  palpebrce  supe- 
riors muscles.  The  first  is  common  to  the  two  ; the  second  be- 
longs to  the  upper  eyelid  only.  The  lower  eyelid  has  no  special 
muscle. 


A.  ORBICULARIS  PALPEBRARUM  MUSCLE. 

§ 1964.  The  orbicularis  palpebrarum  muscle,  naso-palpébral , Ch. 
(JVT.  sphincter  palpebrarum,  s.  nculi ),  is  thin,  membranous  and  circular, 
although  a little  elongated.  It  occupies  the  upper  and  anterior  part 
of  the  face  and  the  lower  and  anterior  part  of  the  skull.  Consequently 
it  is  not  by  any  means  confined  solely  in  the  eyelids. 

Its  internal  part  is  the  slightest  but  the  thickest.  After  leaving  this 
point  it  extends  considerably  upward,  downward  and  outward. 

It  is  attached  above  and  below  to  the  palpebral  ligament,  so  that  it 
may  be  said  to  leave  the  inner  angle  of  the  eye  and  to  return  to  it. 

Besides  this  origin,  several  other  fasciculi  pass  before  and  behind 
the  palpebral  ligament,  whence  it  follows  that  a portion  of  this  muscle 
is  formed  by  uninterrupted  circular  fibres. 

The  orbicularis  muscle  arises  above  by  short  tendinous  fibres  from 
the  upper  extremity  of  the  nasal  process  of  the  superior  maxillary 
bone,  from  the  os  unguis,  and  the  lower  and  anterior  part  of  the  nasal 
and  orbitar  portions  of  the  frontal  bone. 

It  arises  below  by  similar  fibres  from  the  lower  part  of  the  inner 
edge,  and  from  the  inner  part  of  the  lower  edge  of  the  orbit,  which  are 
formed  by  the  ascending  process  and  by  the  body  of  the  superior  max- 
illary bone. 

Its  fibres  separate  especially  in  its  lower  part,  and  fasciculi  are  de- 
tached from  its  outer  part,  some  of  which  go  the  cellular  substance 
and  others  enter  the  zygomaticus  minor  and  the  levator  labii  superioris 
muscles. 

The  internal  part  of  this  muscle  which  is  contained  in  the  eyelids, 
where  it  is  situated  directly  below  the  external  cutaneous  layer,  is 
much  less  extensive  than  the  external.  Its  fibres  are  straighter, 
thinner  and  paler  than  those  of  the  latter,  with  which  it  is  always  un- 


OF  THE  EVE. 


147 


interruptedly  continuous,  although  it  has  been  considered  a special 
muscle,  called  the  ciliaris  muscle. 

B.  LEVATOR  PALPEBRJE  SUPERIORIS  MUSCLE. 

§ 1965.  The  levator  palpebrcz  superioris  muscle,  orbito-palpébral , 
Ch.,  is  very  long,  thin  and  triangular.  It  arises  by  a short  tendon  at 
the  base  of  the  orbit  from  the  periosteum  which  lines  the  upper  part 
of  the  optic  foramen,  and  blends  in  this  place  with  the  tendons  of  the 
rectus  internus  and  rectus  superior  muscles.  It  gradually  becomes 
broader  and  thinner,  advances  directly  under  the  orbitar  plate,  covering 
first  the  inner  and  then  the  whole  of  the  rectus  superior  muscle.  It 
finally  becomes  a very  thin  tendinous  expansion,  often  scarcety  per- 
ceptible, part  of  which  is  attached  to  the  upper  edge  of  the  superior 
palpebral  cartilage,  while  the  other  passes  between  the  orbicularis 
palpebrarum  muscle  and  this  cartilage,  and  extends  to  its  lower  edge 
where  it  is  inserted. 

It  raises  the  upper  eyelid. 

E.  THIRD  EYELID  AND  CARUNCULA  LACHRYMAL  IS. 

§ 1966.  Beside  the  upper  and  lower  eyelids  there  is  also  in  the 
great  angle  of  the  eye  a third  which  is  much  smaller  and  imperfect. 

The  two  palpebral  commissures  differ  in  form.  The  external  is 
more  pointed  than  the  internal.  The  latter  resembles  a small  and 
narrow  prolongation  of  the  palpebral  fissure  towards  the  nose,  the 
separation  of  which  with  the  rest  of  the  fissure  is  marked  very  evi- 
dently by  the  lachrymal  puncta,  and  which  terminates  inward  in  a 
rounded  edge. 

The  third  eyelid  is  found  in  this  space. 

It  has  the  form  of  a triangle,  the  summit  of  which  looks  inward  and 
the  loose  edge  outward  ; this  last  is  semicircular.  It  is  formed  by  a 
fold  of  the  conjunctiva  by  a small  palpebral  cartilage  situated  near  its 
loose  edge,  and  by  a considerable  number  of  sebaceous  glands  united 
in  a rounded  or  slightly  triangular  mass,  between  which  are  small, 
straight  and  very  fine  hairs  analogous  to  the  eyelashes. 

The  sebaceous  glands  are  situated  entirely  inward,  and  project  par- 
ticularly on  its  anterior  face. 

They  are  called  the  caruncula  lachrymalis.  The  external  and  loose 
part  of  the  third  eyelid  which  passes  much  farther  forward  than  the 
caruncula,  has  been  termed  the  semilunar  fold  ( plica  semi-lunaris) . 

This  part  then  really  possesses  all  the  constituent  parts  of  an  eyelid. 
It  differs  from  the  other  eyelids  by  its  smallness  and  in  the  deficiency 
of  an  external  layer  of  skin  and  of  muscular  fibres.  It  is  in  fact  a 
rudiment  of  the  third  eyelid  which  exists  in  most  vertebrated  animals. 
In  fact  the  perpendicular  eyelid  of  these  last  differs  from  it  only  by  its 


148 


DESCRIPTIVE  ANATOMY. 


greater  size.  When  wc  descend  in  the  animal  scale  we  see  that  its 
development  is  always  in  an  inverse  ratio  with  that  of  the  horizontal 
eyelids,  and  that  finally  it  entirely  replaces  them. 

II.  EYEBROWS. 

§ 1967.  The  eyebrows  ( supercilia ) are  short,  strong,  compact  hairs, 
which  gradually  increase  in  size  from  within  outward,  and  which  are 
arranged  in  several  superimposed  striæ.  These  hairs  form  a little 
above  the  upper  eyelid  an  arch,  the  convexity  of  which  looks  upward. 
The  two  arches  they  describe  blend  more  or  less  at  their  inner  part. 

We  may  consider  this  part  of  the  face  as  the  commencement  of  the 
upper  eyelid. 

The  eyebrows  are  moved  each  by  a special  muscle,  the  corrugator 
supcrcilii. 

The  corrugator  supercilii  muscle  ( fronto  sourcilier , Ch.)  is  thick 
and  large.  It  covers  the  inner  part  of  the  upper  edge  of  the  orbit.  It 
is  covered  at  its  origin  by  the  upper  internal  part  of  the  orbicularis  pal- 
pebrarum muscle,  and  by  the  internal  and  inferior  part  of  the  frontalis 
muscle  ; it  arises  by  very  short  tendinous  fibres  from  the  frontal  bone, 
below  the  inner  part  of  the  supraciliary  ridge.  Its  fibres  are  oblique. 
Its  direction  is  outward,  and  it  gradually  becomes  thinner.  It  is  so 
blended,  particularly  in  its  external  part,  with  the  upper  portion  of  the 
orbicularis  palpebrarum  muscle,  which  entirely  covers  it,  and  which 
may  be  considered  as  a deeper  layer  of  this  latter  muscle. 

It  wrinkles  the  eyebrows,  and  the  skin  of  the  forehead  perpendicu- 
larly. 

III.  LACHRYMAL  PASSAGES. 

§ 1968.  The  lachrymal  organs  or  passages  ( organa  lachrymalia , s. 
vice  lachrymales),  form  a special  apparatus,  the  function  of  which  is  to 
secrete  and  excrete  a transparent  liquid  termed  the  tears  (lachrymce).(l) 

This  apparatus  includes  the  lachrymal  gland  and  its  excretory  ducts, 
the  lachrymal  puncta,  and  the  lachrymal  passages , the  lachrymal  sac , 
and  the  nasal  canal.  We  may  annex  to  a certain  extent  the  con- 
junctiva, as  it  is  uninterruptedly  continuous  with  the  excretory  pas- 
sages, the  gland,  and  the  lachrymal  puncta,  and  as,  strictly  speak- 
ing, it  is  only  a considerable  dilatation  of  the  excretory  portion  of  the 
lachrymal  organ. 

A.  LACHRYMAL  GLAND. 

§ 1969.  Only  one  lachrymal  gland  is  commonly  admitted  :(2)  there 
are,  however,  two,  generally  arranged  so  that  one  is  superior,  the  other 

(1)  Berzelius,  Djurkcmi,  vol.  ii.  p.  219-221. 

(2)  N.  Stcnon,  De  glandulis  ocutorum  novisque  corum  vasis  observalwncs  ana- 
tomicœquibus  ver  ilacry  mur  um juntes  detegunlur  ; in  the  Obs.  anat.,  Leyden,  1Ü62. — 


OF  THE  EYE. 


149 


inferior.  Both  belong  to  the  list  of  conglomerate  glands.  They  are 
situated  behind  the  upper  eyelid,  directly  below  the  orbitar  plate. 

The  superior  lachrymal  gland  ( Gl . lachrymalis  superior , s.  innomi- 
nata  Galeni),  is  much  larger  than  the  other.  It  occupies  the  lachry- 
mal depression  of  the  frontal  bone.  It  is  triangular,  and  flattened  from 
above  downward.  The  inferior  (Gl.  congregalœ  JWonroi) ( 1 ) touches 
at  its  posterior  extremity,  the  anterior  part  of  the  preceding,  and 
extends  to  the  external  part  of  the  upper  edge  of  the  cartilage  of  the 
upper  eyelid:  Its  lobules  are  smaller  and  more  remote  from  each  other, 
than  those  of  the  upper. 

Six  or  seven  very  small  canals  arise  from  these  two  glands,  and  go 
from  behind  forward,  from  without  inward,  and  from  above  downward, 
and  open  at  the  side  of  each  other  from  without  inward,  on  the  inner 
face  of  the  upper  eyelid,  near  the  external  angle  of  the  eye. 

B.  LACHRYMAL  PUNCTA  AND  LACHRYMAL  PASSAGES. 

§ 1970.  The  upper  and  the  lower  eyelids  present  each,  at  the  part 
where  the  inner  angle  commences,  and  where  the  orifices  of  the 
Meibomian  glands  terminate,  an  opening,  the  direction  of  which  is 
rather  more  backward,  and  which  may  easily  be  distinguished  from 
those  of  the  palpebral  glands  and  the  lids,  as  its  diameter  is  much 
larger,  and  as  it  is  supported  by  a conical  prominence.  These  two 
openings  are  termed  the  lachrymal  puncta  (P.  1.  superius  et  inferius). 
The  direction  of  the  upper  is  downward,  and  that  of  the  lower  is  up- 
ward. The  latter  is  most  generally  larger  than  the  other. 

These  puncta  are  the  orifices  of  the  lachnjmal  passages  ( canaliculi 
lachrymales,  s.  cornua  limacum ),  which  extend  to  the  lachrymal  sac. 

The  lachrymal  passages  proceed  directly  on  the  edges  of  the  eyelids, 
covered  posteriorly  by  the  internal  cutaneous  laj-er  of  these  lids,  and 
anteriorly  by  the  orbicularis  muscle,  with  which  they  are  so  intimately 
connected,  that  they  are  detached  from  its  fibres  with  great  difficulty. 

The  superior  first  ascends  a little  outward,  in  which  direction  also 
the  inferior  descends.  In  this  part  of  their  course  they  are  very  narrow. 
Then  after  slightly  projecting,  the  superior  goes  inward  and  downward, 
and  the  inferior  upward,  and  both  converge  very  much.  Arrived  at 
the  inner  angle  of  the  eye,  they  pass  under  the  palpebral  ligament, 
and  open  into  the  anterior  and  external  part  of  the  lachrymal  sac,  one 
directly  above  the  other,  but  by  two  distinct  orifices.  They  form  within 
this  cavity  a small  rounded  prominence. 

A whitish  and  smooth  mucous  membrane  forms  their  parietes. 

A.  Monro,  Gntlie  lachrymal  glands  and  duels;  iii  the  Anatomical  and  physiological 
observations , Edinburgh,  173S,  p.  770.  tab.  ii. — J.  J.  Beaux,  Physiologic  de  la  glande 
lachrymale , Paris,  1321. 

(1)  Loc.  cil.,  p.  77. 


VOL.  III. 


20 


150 


DESCRIPTIVE  ANATOMY. 


C.  LACHRYMAL  SAC. 

§ 1971.  The  lachrymal  sac  (saccus  lachrymalis)  differs  much  in  its 
breadth,  direction,  and  structure,  from  the  lachrymal  passages. 

It  is  infinitely  broader  than  they,  but  it  contracts  a little  from  above 
downward. 

It  is  covered  anteriorly  by  the  inner  part  of  the  orbicularis  palpe- 
brarum muscle,  and  is  situated  above  in  the  lachrymal  groove,  along 
which  it  extends  upward  into  the  lachrymal  passages  by  a small  cul-de- 
sac,  and  downward  into  the  nasal  canal.  It  descends  first  from  within 
outward  and  from  behind  forward,  then,  on  arriving  at  the  nasal  canal 
its  direction  is  from  before  backward.  In  its  course  its  diameter  gradu- 
ally diminishes.  It  opens  into  the  anterior  part  of  the  lower  meatus  of 
the  nasal  fossæ,  by  an  opening  which  is  oblique  from  above  downward 
and  from  within  outward,  and  which  is  provided  with  a small  valve. 

It  is  formed  of  three  superimposed  membranes. 

The  external  is  whitish,  and  is  evidently  fibrous,  and  also  serves  as 
a periosteum  to  the  bones  which  receive  the  lachrymal  sac;  but  it  is 
also  very  apparent  on  the  anterior  side  of  the  upper  part  of  the  sac 
which  lodges  the  lachrymal  groove. 

The  middle  is  thin  and  cellular  : it  corresponds  to  the  cellular  tunic 
of  the  mucous  membranes.  The  internal  is  thick,  rough,  spungy, 
verrucous,  and  of  a deep  red.  It  always  secretes  an  abundant  mucus, 
which  oozes  through  the  rounded  and  oblong  orifices  of  small  glands 
arranged  very  compactly. 

This  internal  membrane  is  evidently  the  continuation  of  that  of  the 
nasal  fossæ,  while  that  which  forms  the  lachrymal  passages  is  con- 
tinuous with  the  conjunctiva,  so  that  it  establishes  the  limit  between 
the  eye  and  the  nose.(l) 

(l)  Horner  has  discovered  a new  muscle  of  the  eye,  the  following-  description  of  it 
is  extracted  from  his  Treatise  on  General  and  Special  Anatomy , vol.  ii.  p.  408. 

“The  tensor  tarsi  is  a small  muscle  on  the  orbital  face  of  the  lachrymal  sac.  It  arises 
from  the  posterior  superior  part  of  the  os  unguis,  just  in  advance  of  the  vertical 
suture  between  the  os  planum  and  the' os  unguis.  Having  advanced  three  lines,  it 
bifurcates  ; one  bifurcation  is  inserted  along  the  upper  lachrymal  duct,  and  termi- 
nates at  its  punctum,  or  near  it  ; and  the  lower  bifurcation  has  the  same  relation  to 
the  lower  lachrymal  duct.  The  base  of  the  caruncula  lachrymalis  is  placed  in  the 
angle  of  the  bifurcation.  The  superior  and  the  inferior  margins  of  the  muscle  touch 
the  corresponding  fibres  of  the  orbicularis  palpebrarum,  where  the  latter  is  con- 
nected with  the  margin  of  the  internal  canthus  of  the  eye,  but  may  be  readily  dis- 
tinguished by  their  horizontal  course.  The  nasal  face  of  this  muscle  adheres  very 
closely  to  that  portion  of  the  sac  which  it  covers,  and  also  to  the  lachrymal  ducts. 
The  lachrymal  sac  rises  about  a line  above  its  superior  margin,  and  extends  in  the 
orbit  four  lines  below  its  inferior  margin.  The  orbital  face  of  the  muscle  is  covered 
by  a lamina  of  cellular  membrane,  and  between  this  lamina  and  the  ball  of  the  eye 
are  placed  the  valvula  semilunaris,  and  a considerable  quantity  of  adipose  matter. 

As  the  bifurcated  extremities  of  the  muscle  follow  the  course  of  the  ducts,  they 
are  covered  by  the  tunica  conjunctiva.  When  this  muscle  is  examined  from  be- 
hind, the  eyelids  being  in  situ,  it  becomes  obvious  that  it  is  concave  on  its  orbital 
surface,  and  consequently  convex  on  the  nasal  ; that  the  muscle  is  an  oblong  body, 
half  an  inch  in  length,  and  about  three  lines  wide,  bifurcated  at  one  end  ; and  that  it 


Of  THE  EYE 


151 


ARTICLE  SECOND. 


GLOBE  OF  THE  EYE. 

§ 1972.  The  globe  of  Ike  eye  ( bulbus  oculi),(  1)  often  termed  simply 
the  eye,  is  formed  like  an  almost  regular  globe.  In  the  adult  its 
diameter  is  about  an  inch  : its  length,  however,  exceeds  its  breadth  and 
its  height.  It  occupies  the  anterior  part  of  the  cavity  of  the  orbit,  but 
passes  a little  before  it.  It  is  surrounded  in  every  part  by  an  abundance 
of  fat,  and  also  by  the  muscles  which  move  it,  and  which  contribute 
with  the  optic  nerve,  and  numerous  blood-vessels,  to  retain  it  in  place. 

It  is  formed  by  several  superimposed  membranes  and  the  humors 
contained  by  them.  In  respect  to  the  form  and  the  texture  of  the 
membranes,  and  that  of  the  nature  of  the  humors,  we  may  divide  it 
into  two  parts,  a posterior  and  an  anterior,  the  first  of  which  is  more 
extensive  than  the  other. 

arises  much  deeper  from  the  orbit  than  any  acknowledged  origin  of  the  orbicularis. 
The  superior  fork,  however,  has  a few  of  its  fibres  blended  with  the  ciliaris. 

In  regard  to  the  use  of  this  muscle.  Its  attachment  to  the  posterior  face  of  the  sac 
is  such,  that  it  draws  the  orbital  parietes  of  the  sac  away  from  the  nasal,  and  dilates 
the  sac,  from  the  nasal  face  of  the  latter  being  fixed  to  the  hones.  As  this  muscle 
has  a cylindrical  concavity  on  its  orbital  side,  it  is  evident  that  when  it  contracts  the 
fibres  become  straight,  or  nearly  so,  like  the  fibres  of  the  diaphragm,  and  the  cavity 
of  the  sac  is  enlarged  after  the  same  manner  as  the  cavity  of  the  thorax.  A tendency 
to  a vacuum  being  thus  produced  by  it,  the  valves  or  folds  of  the  internal  membrane 
of  the  sac,  permit  the  vacuum  to  be  filled  more  readily  through  the  puncta  than 
from  the  nose;  and  the  puncta  being  continually  bathed  in  the  tears  of  the  lacus 
lachrymalis,  both  in  the  waking  and  in  the  sleeping  state,  the  tears  are  constantly 
propelled  through  them  by  atmospheric  pressure.  The  evacuation  of  the  sac  is  no 
doubt  accomplished  by  its  own  elasticity,  and  by  the  contraction  of  the  orbicularis  ; 
probably  in  a chief  degree  by  the  latter,  because  in  persons  who  have  epiphora,  or  a 
tendency  to  obstruction  in  the  nasal  duct,  the  accumulation  of  tears  and  matter 
principally  take  place  at  night,  when  the  action  of  the  orbicularis  is  suspended  by 
sleep.  For  these  reasons  we  should  argue,  that  this  little  muscle  is  active  all  the 
time,  both  night  and  day.  To  Dr.  Physick  I am  indebted  for  suggesting  another 
use  for  this  muscle  ; that  of  keeping  the  lids  in  contact  with  the  ball  of  the  eye.  Some 
persons  possess  unusual  voluntary  power  of  this  muscle,  of  which  I have  seen  two 
examples  ; one  in  a lady  ; another  in  a gentleman,  a student  of  medicine.  In  each 
instance  the  individual  could  shorten  so  much  the  internal  angle  of  the  eyelids,  as 
to  conceal  it,  along  with  the  puncta,  in  the  internal  canthus  of  the  orbit.” 

Trasmondi,  on  the  contrary,  thinks  that  it  acts  on  the  lachrymal  sac  and  passages, 
that  it  compresses  the  caruncula  lachrymalis  so  as  to  favor  the  excretion  of  the 
humor  formed  by  its  crypts,  and  that  it  relaxes  or  also  tenses  the  membrane,  so  as  to 
increase  or  diminish  the  base  of  the  lachrymal  sac,  and  to  force  the  tears  into  the 
nasal  canal.  ( Notice  sur  l a découverte  de  deux  nerfs  de  l’œil  humain  ; in  the  Mé- 
langes de  chirurgie  étrangère , Geneva,  1824,  p.  415).  Gery  {Ibid.  p.  453)  does  not 
agree  with  his  fellow-countryman,  and  thinks  with  Horner,  that  this  muscle  serves 
to  adapt  the  lids  to  the  globe  of  the  eye,  and  to  direct  the  tears  into  the  lachrymal 
sac.  F.  T. 

(1)  C.  A.  Rudolpbi,  Diss.  de  oculi  quibusdam  partibus,  Gripswald,  1801.— -Id. 
lieber  einige  Theile  des  Auges  in  his  Anatomisch-physiologische  Untersuchungen , 
vol.  i.  p.  1-30. — Dœllingcr,  Illustratif  ichnographica  oculi  humani,  VVurtzburg, 
1817. — Edwards,  Sur  la  structure  de  l'œil:  in  the  Bulletin  de  la  soc.  philom.,  1814, 
p.  21. — E.  Home  and  F.  Bauer,  Observations  microscopiques  sur  la  structure  de  V oeil  ; 
in  Phil,  trans .,  1822,  p.  76,  and  in  Archiv,  génér.  de  méd.,  vol.  ii.  p.  151. 


152 


DESCRIPTIVE  ANATOMY. 


The  most  external  membrane  is  the  cornea , the  posterior  part  of 
which  is  the  opaque  cornea  or  the  sclerotica , and  the  anterior,  the 
transparent  cornea.  Next  comes  the  middle  membrane,  the  choroid , 
the  anterior  part  of  which  is  termed  the  iris,  and  below  this  is  a 
third,  the  retina,  which  is  a prolongation  or  expansion  of  the  optic 
nerve. 

I.  MEMBRANES  OF  THE  EYE. 

A.  EXTERNAL  MEMBRANES  OF  THE  EYE. 

§ 1973.  The  external  membranes  of  the  globe  of  the  eye  are  much 
firmer  and  thicker  than  the  others.  Its  form  is  determined  principally 
by  them. 

A.  SCLEROTICA. 

§ 1974.  The  sclerotica,  the  opaque  cornea,  or  the  albugineous  mem- 
brane of  the  eye  ( tunica  sclerotica,  s.  albuginea,  s.  cornea  opaca),  covers 
the  posterior  part  of  the  eye,  and  occupies  about  five  sixths  of  its  cir- 
cumference. It  presents  posteriorly,  a little  nearer  its  inner  side  than 
its  centre,  a round  foramen,  or  at  least  it  is  much  thinner  there  than  in 
its  other  parts,  and  there  presents  numerous  small  cribriform  openings, 
through  which  the  fasciculi  of  the  optic  nerve  communicate  with  the 
retina.  It  is  terminated  anteriorly  by  a broad  rounded  opening  which 
recieves  the  transparent  cornea. 

As  it  belongs  to  the  class  of  fibrous  membranes  it  is  white,  brilliant, 
fibrous,  very  elastic  and  solid.  We  may  forcibly  divide  it  into  several 
layers  : but  these  are  united  by  intermediate  filaments. 

The  two  faces  are  smooth.  Numerous  blood-vessels,  the  trunks  of 
the  twigs  distributed  to  the  inner  part  of  the  eye,  intimately  adhere  to 
the  external  ; some  of  these  vessels  perforate  it  posteriorly,  others  more 
anteriorly  at  about  its  centre.  They  all  proceed  within  its  substance 
a greater  or  less  distance,  which  is  proportional  to  their  own  volume. 

Smaller  openings  in  its  posterior  part  give  passage  to  the  ciliary 
nerves,  which  penetrate  from  without  inward  between  it  and  the 
choroid  membrane. 

The  sclerotica  is  not  equally  thick  in  every  part.  It  generally 
diminishes  much  from  behind  forward.  Posteriorly  it  is  about  a line 
thick,  and  about  one  half  of  a line  at  the  edge  of  the  transparent 
cornea. 

The  membrane  is  thinner  in  the  points  which  correspond  to  the 
attachment  of  the  tendons  of  the  recti  muscles  of  the  eye,  than  between 
these  insertions. 

In  the  place  where  the  optic  nerve  communicates  with  the  globe  of 
the  eye,  it  unites  very  intimately  with  the  envelop  given  to  this  nerve 
by  the  dura-mater.  Although  it  is  eight  or  ten  times  thicker,  and  also 


or  THE  EVE 


153 


firmer  than  this  envelop,  we  may  however  consider  them  as  identical, 
since  they  do  not  differ  essentially  in  regard  to  texture, 

§ 1975.  Among  the  superimposed  layers  of  the  sclerotica,  one  may 
be  detached  more  or  less  easily  from  the  others,  and  with  greater 
facility  in  the  early  periods  of  life,  than  in  the  adult.  This  very  thin 
layer  is  a prolongation,  not  of  the  pia-mater  as  has  been  supposed 
since  Zinn’s  time,(  1 ) but  of  the  envelop  sent  by  the  arachnoid  mem- 
brane to  the  optic  nerve,  and  with  which  it  is  evidently  continuous.  It 
forms  a small  bursa  projecting  inward,  around  the  cribriform  plate, 
through  which  the  optic  nerve  enters  the  eye,  and  is  reflected  from  the 
circumference  of  this  layer  on  the  inner  face  of  the  sclerotica,  with 
which  it  unites  intimately,  proceeding  with  it  to  its  anterior  edge. 

There  is  then  between  this  layer  and  the  sclerotica,  exactly  the 
same  relation  as  between  the  dura-mater  and  the  arachnoid  membrane 
within  the  skull  and  the  vertebral  column,  or,  emplojring  a more  gene- 
ral comparison,  as  between  the  hard  substances,  as  the  cartilages  and 
the  fibrous  organs,  covered  with  serous  membranes  and  these  mem- 
branes. 

The  inner  face  of  this  internal  layer  of  the  sclerotica,  is  rather  inti- 
mately united  to  the  choroid  membrane  by  a loose  cellular  tissue,  and 
also  by  the  nerves  and  vessels  which  pass  through  the  external  cap- 
sule of  the  eye.  We  may,  however,  especially  some  days  after  death, 
separate  and  remove  the  sclerotica,  without  injuring  the  choroid  mem- 
brane. ' 

B . TRANSPARENT  CORNEA. 

§ 1976,  The  transparent  cornea  ( tunica  cornea , s.  cornea  pellu- 
cida)( 2)  which  surrounds  the  anterior  part  of  the  eye,  differs  from  the 
sclerotica  in  its  texture  so  much,  that  it  is  impossible  to  apply  the  same 
term  to  these  two  membranes. 

It  represents  a segment  of  a sphere  which  is  a little  smaller  than 
that  of  which  the  sclerotica  is  the  figure,  so  that  it  is  more  convex  and 
projects  slightly  on  the  surface  of  the  latter. 

It  is  always  a little  thicker  than  the  sclerotica,  and  its  thickness  is 
generally  uniform,  except  at  its  circumference,  where  it  gradually  be- 
comes much  thinner,  but  only  in  a slight  extent.  Sometimes,  how- 
ever, it  is  a little  thicker  in  the  centre  than  on  the  edge.  Its  posterior- 
face  always  describes  a concavity  which  corresponds  exactly  to  the 
convexity  of  its  anterior  face. 

The  conjunctiva  extends  towards  the  upper  edge  and  the  lower  edge 
of  its  external  face  for  about  half  a line,  so  that  this  external  face  is 
not  perfectly  round,  but  slightly  elliptical,  The  upper  face,  on  the 

(1)  Zinn,  loc.  cit.,  p.  11 

(2)  B.  D.  Manchart,  Corneæ  oculi  tunicæ  examen  analoviico-physiologicum , Tu- 
bingen, 1743. — Hoffbauer,  Diss.  de  cornea  ejusque  morbis,  Berlin,  1820. — M.  J. 
Chelius,  l’eber  die  durchsichtige  Hornhaut  des  Augest  Carlaruhe,  1818. 


154 


DESCRIPTIVE  ANATOMY. 


contrary,  is  entirely  round.  It  terminates  by  a circular  depression  or 
groove  which  receives  a prominent  edge,  situated  on  the  limit  between 
the  ciliary  ligament  and  the  iris. 

It  always  becomes  much  thinner  and  is  serrated  at  its  point  of  union 
with  the  sclerotica. 

The  two  membranes  are  united  in  three  different  ways. 

Sometimes  the  anterior  face  gradually  diminishes,  so  that  the  trans- 
parent cornea  is  partly  covered  by  the  sclerotica. 

Sometimes  the  two  faces  gradually  become  thinner,  and  the  cornea 
is  inserted  in  a channel  grooved  on  the  anterior  edge  of  the  sclerotica. 

Finally  sometimes  the  internal  face  insensibly  disappears,  and  the 
cornea  rests  a little  on  the  anterior  edge  of  the  sclerotica. 

The  first  is  the  most  common  and  the  last  the  rarest  arrangement. 

§ 1977.  The  transparent  cornea  is  formed  of  several  layers  having 
between  them  a limpid  fluid  which  are  separated  more  easily  than 
those  of  the  sclerotica,  and  which  are  united  by  a loose  cellular  tissue. 

This  fluid  transudes  after  death.  Its  evaporation  causes  in  part  the 
opacity  and  collapse  of  the  cornea,  which  then  occur. 

The  posterior  face  of  the  cornea  is  covered  by  a thin,  pellucid,  homo- 
geneous and  slightly  extensible  membrane,  which  tears  evenly  when 
forcibly  extended  and  is  easily  detached  from  it  by  a slight  maceration 
or  by  boiling.(l)  This  membrane  is  attached  to  the  edge  of  the  cornea, 
and  does  not  proceed  at  least  sensibly  on  the  iris.  It  has  been  termed 
the  membrane  of  the  aqueous  humor  (mem.  humoris  aquei ) I his  term 
is  inappropriate,  as  it  docs  not  seem  to  secrete  the  aqueous  humor.*  (2) 

B.  CHOROID  MEMBRANE  AND  IRIS. 

§ 1978.  Directly  below  the  external  tunic  of  the  globe  of  the  eye  is 
another  membrane  of  about  the  same  extent  and  also  composed  of  two 
halves  differing  in  their  organization.  The  posterior  is  termed  the 
choroid  membrane,  and.  the  anterior,  which  is  much  smaller,  the  iris. 

(1)  B.  Duddell,  Treatise  on  the  diseases  of  the  horny  coat  in  the  eye , London,  1729. 
— J.  Descemet,  An  sola  lens  crystallina  cataractœ  sedes , Paris,  1758. — Id.  in  the 
Mem.  des  sav.  étrangers , book  i. — Demours,  Lettre  à M.  Petit , Paris,  1767. — The 
details  of  the  quarrel  between  Descemet  and  Demours,  in  regard  to  the  discovery  of 
this  membrane,  are  given  in  the  Journ.  de  med .,  1769,  1770,  1771. 

* Professor  Schlemm  of  Berlin,  asserts  that  the  cornea  is  well  supplied  with 
nerves  : “ They  arise  from  the  ciliary  nerves  which  divide  behind  the  ciliary  liga- 
ment into  a superficial  and  a deep-seated  order  of  filaments.  The  latter  are  larger 
and  more  numerous,  and  are  distributed  to  the  iris  ; the  superficial  however  enter 
the  sclerotica  on  a level  with  the  ciliary  ligament,  from  whence  they  extend  forward 
to  enter  the  groove  of  the  edge  of  the  cornea  which  is  united  with  the  corresponding 
border  of  the  sclerotica,  and  traverse  the  posterior  part  of  the  cornea  until  they 
become  lost  by  their  extreme  tensity  upon  that  membrane.”  (Am.  Journ.  of  the 
Med.  Sciences,  Nov.,  1830,  p.  211.) 

(2)  S.  Sawrey  in  1807  claimed  the  discovery  of  this  membrane,  which  had  been 

vaguely  imagined  by  Duddell,  and  which  in  fact  had  been  discovered  by  Demours 
or  Descemet.  (An  account  of  a newly  discovered  membrane  in  (he  human  eye,  Lon- 
don, 1807.)  F.  T. 


OF  THE  EYE, 


155 


A.  CHOROID  MEMBRANE. 

§ 1979.  The  choroid  membrane  (tunica  vasculosa,  s.  choroidea)(  1) 
corresponds  to  the  sclerotica.  It  extends  from  the  anterior  edge  of  this 
membrane  to  the  entrance  of  the  optic  nerve  for  which  it  presents  a 
rounded  opening  and  to  which  it  is  directly  united,  particularly  along 
the  course  of  the  nerves  and  vessels,  in  its  whole  extent  by  rather  a 
loose  cellular  tissue.  The  union  between  the  two  membranes  is  only 
interrupted  here  and  there  by  the  ciliary  nerves  and  the  long  ciliary 
arteries,  which  proceed  between  them  from  behiird  forward. 

The  inner  face  of  the  choroid  membrane  is  not  attached  to  the  re- 
tina, although  they  are  in  direct  contact. 

§ 1980.  Near  the  anterior  extremity  of  the  choroid  membrane  the 
mucous  tissue  becomes  much  thicker  in  the  outer  face  of  the  mem- 
brane, and  forms  a whitish  ring  about  one  line  broad,  called  the  ciliary 
ligament,  the  commissure  of  the  choroid  membrane , Ch.  (L.  ciliare,  or- 
biculus  ciliaris,  circulas  ciliaris,  plexus  ciliaris).  This  ring  attaches 
the  choroid  membrane  to  the  sclerotica  more  firmly  than  hi  the  rest  of 
its  extent  ; but  it  is  united  to  the  sclerotica  much  less  intimately  than 
to  the  choroid  membrane,  which  is  thinner  in  the  part  corresponding  to 
it,  so  that  the  latter  can  be  easily  detached  from  the  opaque  cornea, 
while  this  is  not  the  case  with  the  ciliary  ligament,  which  may  conse- 
quently be  considered  as  forming  part  of  it. 

The  internal  circumference  of  the  ciliary  ligament  is  bounded  by 
a narrow  but  very  evident  white  projection,  which  fils  exactly  into 
a groove  on  the  circumference  of  the  inner  face  of  the  transparent 
cornea. 

Before  this  ring  is  the  iris,  which  is  intimately  united  with  it. 

B.  CILIARY  BODY. 

§ 1981.  The  inner  face  of  the  choroid  membrane  is  singularly 
changed  in  this  place,  where  it  forms  the  ciliary  body  ( corona  ciliaris, 
s.  orbiculus  ciliaris,  corpus  ciliare,  tunica  ciliaris). (2 ) In  fact  on 
leaving  the  external  edge  of  the  ciliary  ligament  it  forms,  inward  and 
for  the  breadth  of  about  a line  and  a half,  numerous  small  folds,  whence 
come  a great  number  of  slightly  prominent  rays  which  go  from  with- 
out inward.  Another  smaller  and  more  internal  circle  then  succeeds, 
formed  by  more  distinct  folds,  the  inner  edge  of  which  is  convex  and 

(1)  Ruysch,  Ep.  an  at.  xiii. — L.  Heister,  Diss.de  tunica  choroidcâ , in  the  Ease, 
diss.  med.,  Leyden,  1745. — B.  S.  Albinus,  Dc  tunica  Ruyschianâ  et  choroidcâ  oculi  ; 
in  the  Ann.  acad.,  1.  vii.,  cap.  iv. 

(2)  J.  G.  Zinn,  De  ligament  is  ciliaribus  progrefifnma,  Gottingen,  ] 753. — Doellinger, 
tlur  les  procès  ciliares  dans  l’œil  dc  l’homme;  in  the  J\ov.  actanat.  cut.,  voL  ix., 
p.  274. 


156 


DESCRIPTIVE  ANATOMY. 


which  become  more  prominent  from  without  inward,  and  terminate  in 
a rounded  edge.  These  folds,  which  are  termed  ciliary  processes 
(processus  ciliaris),  are  fewer  in  number  although  very  numerous,  as 
there  are  about  seventy.  They  are  however  much  more  remote  from 
each  other  than  the  external.  Their  anterior  extremity  is  loose.  They 
arc  attached  to  the  large  circumference  of  the  crystaline  capsule  by 
the  anterior  part  of  their  adherent  edge.  The  posterior  part  of  all  this 
region  of  the  choroid  membrane  adheres  very  intimately  to  the  ex- 
ternal face  of  the  ciliary  ligament,  for  its  folds  are  received  into  the 
depressions  of  this  latter,  the  form  of  which  corresponds  exactly  to 
theirs,  so  that  in  this  part  the  inner  face  of  the  choroid  membrane  is 
firmly  united  to  the  subjacent  parts,  and  when  we  attempt  to  detach 
it  in  the  recent  state  the  ciliary  ligament  is  generally  torn. 

§ 1982.  The  choroid  membrane  is  soft  and  thin,  but  its  tissue  is 
firm  and  solid.  On  removing  the  coat  of  the  pigment  it  appears 
whitish  and  slightly  transparent.  It  is  almost  entirely  formed  by 
blood-vessels  which  are  very  distinct  on  its  two  faces,  especially  on 
the  external. 

Some  of  these  vessels  are  arteries  and  others  veins,(l)  but  the  latter 
are  much  more  numerous. 

§ 1983.  The  arteries  of  the  choroid  membrane,  termed  the  ciliary 
arteries  (A.  ciliares),  are  principally  of  two  kinds. 

The  long  ciliary  arteries  (A.  ciliares  longa)  are  longer  and  more 
superficial  than  the  others  ; there  are  generally  but  two,  an  external 
and  superior  and  an  internal  and  inferior.  These  two  arteries  are 
situated  more  or  less  nearly  opposite  each  other.  After  passing 
through  the  sclerotica  at  its  posterior  part  they  are  situated  on  the 
anterior  part  of  the  choroid  membrane,  proceed  directly  from  behind 
forward  without  sending  off  any  very  large  branch,  and  are  distri- 
buted in  the  iris.  Hence  they  do  not  really  belong  to  the  choroid 
membrane. 

The  short  or  posterior  ciliary  arteries,  uvéales , Ch.  (A.  ciliares  breves , 
s.  postenores),  are  much  smaller  but  more  numerous  than  the  long. 
There  are  usually  twenty  or  more  of  them  of  different  sizes.  They 
perforate  the  sclerotica  more  posteriorly  and  internally  than  the  pre- 
ceding, nearer  the  optic  nerve,  and  soon  enter  the  choroid  membrane. 
They  there  divide  into  twigs  which  are  given  off  at  acute  angles, 
frequently  anastomose  together,  especially  in  the  anterior  part  of  the 
choroid  membrane,  and  form  forward,  behind  the  external  edge  of  the 
ciliary  body,  a circle  composed  of  a very  complex  network. 

The  twigs  they  produce  in  dividing  are  parallel,  and  proceed  very 
closely  from  behind  forward.  At  the  posterior  part  of  the  choroid 
membrane  they  are  situated  on  its  outer  face,  but  towards  the  centre 
of  the  globe  of  the  eye  they  pass  through  it  and  go  to  its  internal  face, 

(1)  J.  E.  Hebenstreit,  De  rosis  sanguiferis  oculi,  Leipsic,  1742. — J.  G.  Zinn,  Di 
casts  subtilioribus  oculi  et  coehlcce  auris  internee , Gottingen,  1753. 


OF  THE  EVE, 


157 


where  consequently  they  are  more  distinctly  perceptible  than  in  the 
external. 

§ 1984.  The  veins  of  the  choroid  membrane  are  easily  distinguished 
from  the  arteries  by  their  course  and  their  larger  size. 

Their  branches  are  very  compact,  radiate  from  before  backward  and 
from  without  inward,  form  large  arches,  and  divide  into  twelve  or  four- 
teen small  twigs  which  pass  through  the  sclerotica  at  about  the  centre 
of  the  globe  of  the  eye,  proceed  a few  lines  from  before  backward  in 
this  membrane,  and  reunite  in  four  or  five  larger  trunks  which  pass 
out  of  the  eye  at  its  posterior  part  and  enter  the  ophthalmic  veins. 
Four  of  these  trunks  are  much  larger  than  the  rest,  some  of  which 
proceeding  also  from  before  backward,  receive  the  twigs  coming  from 
the  iris. 

These  veins  have  been  termed  from  their  numerous  curves  the  vasa 
vorticosa.  They  are  more  superficial  than  the  arteries,  and  are  also 
more  external  at  the  anterior  part  of  the  choroid  membrane  and  form 
its  external  layer. 

Besides  these  veins  there  are  others,  the  long  or  anterior  ciliary 
veins  (r.  ciliares  longœ,  s.  anteriores ),  which  accompany  the  long 
ciliary  arteries,  return  from  the  iris,  and  receive  no  considerable  rami- 
fications from  the  choroid  membrane.(l) 

§ 1985.  The  blood-vessels  and  the  mucous  tissue  which  supports 
them  are  the  only  organic  elements  visible  in  the  choroid  membrane. 
Those  fibres  which  are  directed  from  before  backward,  and  are  ad- 
mitted by  several  anatomists  to  exist,  have  never  been  seen  by  us,  and 
even  the  ciliary  body  seems  only  a very  complex  tissue  of  vessels. 

§ 1986.  The  internal  face  of  the  choroid  membrane  does  notap- 
pears  perfectly  smooth  to  the  naked  eye,  but  presents,  particularly  if 
the  eye  be  injected,  numerous  small  floating  flocculæ  which  give  it  a 
downy  appearance  ; this  is  much  more  evident  if  we  use  the  micro- 
scope. These  flocculæ  are  very  well  developed  in  the  ciliary  body. 
They  are  mostly  formed  by  a very  compact  tissue  of  vessels,  particu- 
larly in  the  posterior  region  of  the  choroid  membrane,  the  inner  face  of 
which  is  almost  entirely  covered  by  them,  while  they  leave  it  much 
looser  anteriorly. 

§ 1 987.  The  internal  face  of  the  choroid  membrane  cannot  be  con- 
sidered as  a special  membrane  in  man,  as  we  cannot  divide  it  into  two 
layers.  Ruysch  first  asserted  this  opinion,  while  his  son  termed  this 
coat  the  tunica  Ruyschiana.  It  is  also  incorrect  to  admit  as  the  villo- 
glandular  tunic  {2)  or  the  supra-choroid  membrane  ( membruna  supra- 
choroidca){3),  another  membrane  situated  on  the  outside  of  the  choroid, 
which  would  be  the  second  middle  tunic  of  the  eye,  or  even  the  third, 

(1)  See  the  plate  of  the  vessels  of  the  choroid  membrane,  in  S corn  inerring,  lieber 
das  feinste  Gefassnelz  der  Aderhaut  im  Augäpfel, -1818. 

(2)  B.  A.  Stier,  De  tunicâ  quadam  oculi  novissime  delectà , Halte,  1759. 

(3)  Montain,  in  the  Journal  de  mcd.,  vol.  lvii. — Bull,  de  la  soc.  mid.  d’Emul. , 
1807,  p.  330. 

Vol  111 


21 


156 


DESCRIPTIVE  ANATOMY. 


by  admitting  the  tunica  Ruyschiana,  and  which  has  been  regarded  as 
belonging  to  the  class  of  serous  membranes.(l) 

Finally  it  is  still  more  incorrect  to  represent  the  choroid  coat  as 
formed  by  live  superimposed  layers, (2)  of  which  the  second,  third,  and 
fourth  form  the  proper  choroid  membrane,  and  the  other  two  the  two 
membranes  mentioned 

C,  IRIS. 

§ 1988.  The  im( 3)  is  a circular  membrane  perforated  in  its  centre 
with  a rounded  and  nearly  concentric  opening,  termed  the  pupil. 
This  opening  is  a little  narrower  on  its  inner  side,  which  looks  towards 
the  nose,  than  in  the  rest  of  its  course, (4)  and  its  external  edge  is  at- 
tached to  the  anterior  edge  of  the  choroid  membrane,  viz.  to  the  ciliary 
ligament.  Finally,  it  is  entirely  loose  in  the  chamber  of  the  eye,  where 
it  forms  a transverse  septum  extended  from  above  downward  and  from 
light  to  left,  which  divides  this  chamber  into  two  compartments,  an 
anterior  and  a posterior , communicating  by  the  opening  of  the  pupil. 

The  iris  forms  the  posterior  wall  of  the  anterior  chamber  of  the  eye, 
and  the  transparent  cornea  forms  its  anterior  wall.  It  constitutes,  on 
the  contrary,  the  anterior  wall  of  the  posterior  chamber,  the  posterior 
wall  of  which  is  formed  by  the  anterior  face  of  the  cryslaline  lens, 
and  the  anterior  edge  of  the  ciliary  body. 

The  posterior  wall  of  the  iris  is  also  termed  the  uvea. 

In  man  it  is  straight  and  not  convex  anteriorly,  as  has  been  as- 
serted.^) It  is  nearer  the  anterior  face  of  the  crystaline  membrane 
than  the  posterior  face  of  the  transparent  cornea.(6)  The  space  on 
its  external  face  where  it  is  greatest,  between  it  and  the  cryslaline 
membrane,  is  not  even  half  a line,  but  in  the  centre  it  is  only  a quarter 
of  a line.  Its  centre  is  about  a line  distant  from  the  transparent  cornea, 
but  its  outer  edge  is  much  nearer  this  membrane. 

Its  extent  from  without  inward  varies  extremely  It  is  not  only  often 
morbidly  dilated  to  such  an  extent  that  the  pupil  almost  entirely  dis- 
appears, and  sometimes  contracts  so  much  as  to  be  invisible  or  nearly 
so,  but  also  in  the  normal  state  it  dilates  and  contracts  rapidly  under 
the  influence  of  certain  external  and  internal  causes. (7)  By  carefully 

(1)  Docllingcr,  loc.  cit.,  p.  G. 

(21  Hovius,  De  circular l humorum  motu,  Leyden,  17  LG,  p.  29. 

(3)  Maunoir,  Mémoire  sur  l'organisation  de  l’iris , et  V opération  de  la  pupille  arti- 
ficielle, Paris,  1812. 

(4)  Winslow,  Observations  sur  la  mécanique  des  muscles  obliques  de  l’œil , sur 
l'iris,  &c.  ; in  the  Mém.  de  Paris,  1721,  p.  4G3. — Littleton,  Sur  les  causes  d’où 
dépend  la  largeur  de  la  pupille  ; in  Bradley,  Med.  and  phvs.  Journal,  vol.  xxxvi., 

p.  89. 

(5)  Petit,  Mém.  sur  les  yeux  gelés,  dans  lequel  on  détermine  la  grandeur  des 
chambres  qui  renferment  l’humeur  aquesc  ; in  the  Mém.  do  Paris,  1725,  p.  54. 

(G)  Ibid.,  1728,  p.  295  and  408. 

(7)  J.  G.  Zinn,  De  motu  uvcœ  ; in  tue  Cumin.  GolL,  vol.  i. — F.  Fontana,  Dei  molt 
dcll'iride , Lucca,  1765, — J F Blumenbach,  De  oculis  leucaethiopum  cl  molli 


or  THE  EYE 


1 59 


examining  all  the  circumstances  which  belong  to  these  two  pheno- 
mena we  conclude  that  the  active  state  of  the  iris  js  that  of  dilatation, 
the  passive  that  of  contraction 

§ 19S9.  This  membrane  is  much  thicker  in  its  larger  and  external 
than  in  its  internal  part,  where  it  seems  to  be  divided  obliquely  from 
without  inward  and  from  before  backward,  and  terminates  there  in  a 
thin  edge.  The  most  internal  part  excepted,  the  iris  is  three  or  four 
times  thicker  than  the  choroid  membrane. 

Its  external  and  internal  edges  are  more  deeply  colored  than  the 
intermediate  parts.  The  darkest  part  of  the  membrane  is  a small 
portion  of  the  inner  surface  situated  a little  on  the  outer  side  of  the 
inner  edge.  This  dark  place  and  the  portion  of  the  iris  between  it  and 
the  pupil  is  called  the  small  or  the  internal  circle  ( annulus  minor , s. 
internus) . The  rest  of  the  membrane  is  termed  the  great  or  the.  ex- 
ternal circle  ( annulus  major,  s.  externus). 

The  whole  of  the  anterior  face  of  the  iris  is  entirely  colored.  The 
posterior  is  colored  only  in  the  portion  corresponding  to  the  small 
circle  : all  the  rest  is  whitish,  but  covered  with  a dark  mucus  (§  1997), 
The  anterior  face  is  the  seat  of  the  peculiar  color  of  the  eyes.  It  is 
every  where  covered  by  very  minute  and  differently  colored  flocculæ, 
which  with  the  streaks  of  pigment  abovementioned  on  the  posterior 
face  are  the  grounds  of  the  different  color  of  the  eyes, 

§ 1990.  We  observe  both  on  the  anterior  and  the  posterior  face  of 
the  iris  circular  fibres  which  are  slightly  undulatory,  and  longitudinal 
fibres  which  radiate  from  without  inward.  The  first  are  particularly 
evident  near  the  outer  and  inner  edge.  The  others  are  more  distinct 
on  the  anterior  face  ; they  are  larger  and  more  perceptible  in  the  great 
than  in  the  small  circle 

Some  of  these  fibres  are  whitish  and  alternate  with  others  less  ma- 
nifestly  gray.  The  first  divide  frequently  at  acute  angles  into  a con- 
sidererable  number  of  small  branches,  which  anastomose  on  the  outer 
circumference  of  the  small  circle,  giving  rise  to  arches  which  are  convex 
forward,  and  thus  form  a complex  crown  from  which  smaller  and  closer 
longitudinal  striæ  emanate  ; these  radiate  in  the  internal  circle  to  the 
edge  of  the  pupil, 

§ 1991,  The  iris  is  soft  and  spungy. 

It  i3  mostly  composed  of  nerves  and  vessels  united  by  mucous  tissue, 
and  very  probably  also  of  fibres,  the  seat  of  the  contraction  and  dilata- 
tion mentioned  above  (§  1988). 


iridis,  Gottingen,  1785. — F.  llildcbrandt,  De  motu  iridis,  Brunswick,  1786. — Doem- 
ting,  Ueber  die  Ursache  der  Bewegung  der  Regenbogenhaut  ; in  Reil,  Archiv.  Jur 
Physiologie , vol,  v. — Oaldani,  Intorno  di  movimenti  dcWiride  ; in  the  Mem.  della 
soc.  ital.,  vol.  xiv.,  pt.  2,  p.  101-114. — C.  A.  F.  Kluge,  Diss.  de  iridis  motu,  Erford, 
1S06.— S.  S.  Guttentag-,  De  iridis  motu,  Breslau,  181 5. — Littleton,  On  the  couses 
which  influence  the  sise  oj  the  pupil  ; in  the  Land.  mcd.  and  phys.  journal,  vol.  Ivi  , 
1816  p.  89,  265, — E H Weber  Traci  ulus  dr  motu  iridis,  Lcipsp  • 1821, 


160 


DESCRIPTIVE  ANATOMY. 


§ 1992.  The  nerves  of  the  iris  (JV',  ciliares)(  1)  arise  from  the  first 
branch  of  the  fifth  pair,  from  the  sixth  pair  and  the  great  sympathetic 
nerve,  are  about  twenty  in  number,  and  perforate  the  sclerotica  a little 
behind  the  centre  of  the  great  diameter  of  the  eye,  pass  some  lines  even 
in  the  substance  of  this  membrane,  are  then  situated  between  it  and 
the  outer  face  of  the  choroid  membrane,  adhere  but  slightly  to  these  two 
coats,  proceed  from  behind  forward  without  giving  off  any  branch,  and 
arrive  at  the  external  edge  of  the  ciliary  ligament.,  directly  behind  which 
they  generally  divide  at  an  acute  angle  into  two  branches.  These 
branches  go  forward  on  the  anterior  face  of  the  chorokTmembrane  un- 
der the  ciliary  ligament  and  arrive  at  the  anterior  face  of  the  iris, 
where  they  form  the  whitish  and  radiating  filaments  there  observed  ; 
in  the  course  of  . these  are  rounded  filaments  which  are  perhaps  gan- 
glions. 

The  ciliary  nerves  are  unusually  large  in  proportion  to  the  iris,  and 
hence  this  membrane  is  one  of  the  parts  of  the  body,  if  not  the  very 
part,  which  possesses  the  most  nerves. 

§ 1993.  The  vessels  of  the  iris  arise  principally  from  the  long  or 
anterior  ciliary  vessels. 

E-ach  of  the  two  long  ciliary  arteries  divides  below  the  ciliary  liga- 
ment into  two  branches,  which  go  to  meet  the  two  corresponding 
branches  of  the  other  arterial  trunk,  and  which  by  anastomosing  with 
them  form  on  the  external  edge  of  the  iris  a crown  slightly  convex 
forward,  from  which  numerous  twigs  arise  ; the  latter  radiate  towards 
the  inner  edge  of  the  membrane  and  still  bifurcate,  communicating  here 
and  there  by  transverse  ramuscules.  They  anastomose  together  on 
the  outer  edge,  of  the  internal  ring  so  as  to  form  at  the  opening  of  the 
pupil  a more  or  less  concentric  circle  ; from  this,  new  radiating  twigs 
arise  and  go  to  the  small  circumference,  but  several  of  them  however 
come  directly  from  the  rays  of  the  great  external  arterial  circle. 

Besides  the  arterial  twigs,  the  iris  also  contains  many  little  veins 
which  enter  some  into  the  long  ciliary  veins  and  others  into  the  vasa 
vorticosa.  As  they  cannot  be  filled  except  by  injecting  them  through 
the  arteries,  or  as  when  injected  through  the  venous  trunks,  they  are 
filled  less  perfectly  than  the  arteries,  the  veins  seem  fewer  and  form 
but  small  arches. (2) 

These  vessels  are  most  apparent  on  the  anterior  face  of  the  iris,  to 
which  they  seem  but  loosely  attached. 

They  certainly  carry  red  blood,  since  the  membrane  [bleeds  when 
wounded,  and  their  reddish  color  is  very  evident  in  the  eyes  of  albinos, 
where  the  pigment  continues  colorless  from  a primitive  deviation  of 
formation.  (3) 

§ 1994.  Even  in  the  most  perfect  injections,  the  iris  still  seems  to  be 
formed  of  more  or  less  evident  yellowish  white  fibres,  which  as  we 

(1)  Tiedemann,  Diss.  dc  ganglio  ophihalmico  el  nenis  ciliaribus  animalium,'  Land- 
shut,  1815. 

(2)  Zinn,  loe.  cit.,  p.  <J4. 

(3)  Monro,  Ucber  den  Bau  der  Fische,  Lcipsic,  1787,  r>-  74, 


OF  THE  EYE 


161 


have  already  stated;  seem  to  be  the  seat  of  the  motions  executed  by 
this  membrane. 

Several  anatomists,  as  Drelincourt,(l)  Ruysch,(2)  and  Monro, (3) 
formally  adopt  this  opinion,  or  are,  like  Zinn, (4)  very  much  inclined 
to  it. 

They  assert  that  some  of  the  fibres  are  radiated  and  others  circular  : 
the  first  extend  from  the  external  to  the  internal  circle,  where  Ruysch 
thinks  that  they  are  even  attached  by  small  tendons  : the  circular  form 
most  of  the  internal  circle  of  the  iris. (5)  In  contracting,  the  longitu- 
dinal fibres  dilate  the  pupil,  while  the  circular  contract  it. 

Beside  the  circular  fibres  which  are  admitted  by  Monro  and  Ruysch, 
we  have  sometimes  observed  on  the  anterior  face  of  the  iris,  towards 
its  outer  edge,  some  very  evident  circular  fasciculi,  corresponding  to 
those  discovered  in  the  same  place  in  the  eye  of  the  ox  by  Monro  ;(6) 
but  neither  the  anatomy,  nor  the  observation  of  the  vital  phenomena  of 
the  iris,  seem  to  us  to  justify  the  admission  of  radiating  longitudinal 
fibres. 

§ 1996.  The  iris  in  man  can  be  divided,  but  not  naturally,  into  two 
layers,  an  anterior  or  the  proper  iris,  and  a posterior  or  the  uvea,  and 
these  cannot  be  separated  except  in  small  portions.  It  is  also  uncer- 
tain whether  its  anterior  face  be  lined  by  a prolongation  of  the  mem- 
brane of  Demours  ; at  least  it  is  here  also  much  thinner  than  on  the 
posterior  face  of  the  transparent  cornea,  and  its  nature  is  different. 

§ 1 997.  Opinions  vary  in  regard  to  the  manner  in  which  the  iris 
and  choroid  membrane  are  united.  Some  assert  that  the  iris  is  a pro- 
longation of  the  latter  ; others  think  that  it  should  be  regarded  as  a 
distinct  membrane. 

The  arguments  in  favor  of  the  second  opinion  are  : 

1st.  The  greater  thickness  of  the  iris. 

2d.  Its  numerous  nerves,  while  the  choroid  membrane  has  none. 

3d.  The  fewer  vessels  which  carry  blood  to  it,  which  differ  in  their 
origin  and  arrangement  from  those  of  the  choroid  membrane. 

4th.  The  difference  between  the  two  membranes  in  respect  to  their 
vital  phenomena,  since  the  iris  is  highly  contractile,  while  the  choroid 
membrane  possesses  no  contractility. 

We  may  also  add  that  the  great  edge  of  the  iris  is  easily  detached 
after  a maceration,  which  does  not  continue  long  enough  to  destroy 
the  continuity  of  the  tissue  either  of  this  or  of  the  choroid  membrane 

(1)  Prœlud.  anat.  Opp.  omit.,  p.  195. 

(2)  Respons.  ad  epist.  anat.  xiii-,  Thcs.  anat,  ii,,  p.  13-15. 

(3)  Loc.  at.,  p.  110-115. 

(4)  Loc.  cit.,  p.  91,|95. 

(5)  Monro  (loc.  cit.,  tab,  3). 

(6)  Loc.  cit.,  tab.  2. 


162 


OESCRirTIVE  ANATOMY 


D.  PIGMENT, 

§ 1997.  The  two  faces  of  the  choroid  membrane  and  the  posterior 
face  of  the  iris  or  the  uvea,  in  the  normal  state,  are  covered  with  a 
brownish  colored  substance,  termed  the  pigment  ( pigmentum  ni- 
grum).(])  In  some  parts’,  particularly  on  the  posterior  face  of  the 
iris,  this  pigment  can  be  detached  in  a greater  or  less  extent  as  a fine 
and  coherent  membrane.  In  some  places,  particularly  on  the  inner 
face  of  the  ciliary  body,  especially  between  the  processes,  and  the  pos- 
terior face  of  the  iris,  and  generally  in  the  internal  regions,  it  is  more 
abundant,  deeper  in  color,  and  more  attached  to  the  adjacent  parts. 
There  is  less  on  the  external  than  on  the  internal  face  of  the  choroid 
membrane,  although  that  which  exists  there  does  not  differ  essentially 
from  that  found  in  other  parts.  There  is  none  on  the  posterior  part  of 
the  inner  face  of  the  choroid  membrane  around  the  opening  which 
gives  passage  to  the  optic  nerve,  so  that  the  choroid  coat  is  white  in 
this  place. 

The  pigment  is  composed  of  a peculiar  mucous  substance  and  of 
another  coloring  substance,  the  first  of  which  connects  all  the  mole- 
cules together,  so  that  they  have  the  form  of  a membrane.  In  regard 
to  mechanical  structure,  this  coloring  substance  is  composed  of  glo- 
bules. These  globules  are  not  perfectly  black,  but  only  present  occa- 
sionally small  points  of  a deeper  tint.  Their  form  is  irregularly  round 
They  arc  smaller  in  the  ciliary  processes,  but  are  arranged  in  several 
superimposed  layers  more  uniformly  black.  In  regard  to  their  che- 
mical composition,  they  contain  a considerable  quantity  of  iron  and  also 
of  carbon,  which  forms  almost  half  of  them,  so  that  of  all  parts  of  the 
body  they  contain  the  most  of  this  elementary  substance. (2)  The 
iron  is  the  cause  of  their  heaviness  but  not  the  source  of  their  color, 
since  the  quantity  of  this  metal  in  the  reto  mucosum  of  the  skin 
of  the  negro  is  small,  and  even  leas  than  in  that  of  the  Caucasian 
race.(3) 

The  pigment  is  essentially  so  similar  to  the  retc  mucosum,  that  we 
may  admit  they  arc  the  same,  whence  it  follows  that  the  pigment  is 
not  a secreted  fluid  but  a solid  tissue,  an  organic  element  possessing  a 
special  form. 

(1)  Morulini,  De  oculi  pigmenta  ; in  the  Comm.  Donon.,  vol.  vii.,  p.  29. — Elsaesser, 
De  pigmento  oculi  nigra,  Tubingen,  1800. — L.  Gmelin,  IJiss,  sistens  indagalionem 
chimicam  pigmenti  nigri  oculorvm  taurinorum  cl  vilulinurum , adnexis  quibusdam 
in  id  animadversionibus  physiologicis,  Gottingen,  1812.— F,  Monclini,  Sul  nero  pig- 
mento  dell'  occhio  ; in  the  Opuscoli  scicntijiclii  di  Bologna , 1818,  l'asc,  vii-,  p 15-27. 
— Berzelius,  Djurlcemi,  ii.,  n 201 

(2)  Berzelius,  in  the  Mea.  chir.  trano.,  vol.  iii.,  p.  255. — Coli,  in Mondini  jun.,  loc. 
cit.,  p.  17. 

(3)  Coli,  loc.  cit.,  p.  26. 


or  THE  EYE 


163 


C.  KETINa. 

§ 1998.  The  third  distinct  membrane  of  the  eye  is  the  retina. { 1) 
It  is  the  expansion  of  the  optic  nerve,  the  anterior  extremity  of  which 
contracts  much  in  passing  through  the  sclerotica,  but  more  gradually 
and  more  insensibly  at  its  inner  than  at  its  outer  part,  so  that  the  nerve 
describes  an  arch  much  larger  outward  than  inward. 

Before  the  anterior  extremity  of  the  optic  nerve  the  sclerotica  pre- 
sents a surface  with  numerous  foramina,  through  which  the  fasciculi 
of  the  nerves  pass.  Beyond  this  cribiform  plate  the  extremity  of  the 
nerve  forms  a small  mammillary  prominence,  from  which  the  expan- 
sion of  thç  retina  arises  ; this  terminates  forward  at  the  posterior  ex- 
tremity of\he  ciliary  body  by  a straight  edge  more  or  less  evidently 
enlarged,  which  is  unconnected  with  the  crystalline  capsule. (2) 

§ 1999.  The  retina  is  white,  thin,  homogeneous,  and  destitute  of 
fibres,  equally  thick  in  every  part,  excepting  one  small  point  of  its 
extent  posteriorly.  It  is  composed,  in  a measure,  of  two  layers,  an 
external,  which  is  medullary,  and  an  internal,  formed  by  cellular  tissue 
and  vessels.  The  latter  separates  the  medullary  layer  from  the  vit- 
reous body.  We  cannot  however  insulate  the  two  layers  from  each 
other  so  as  to  obtain  one  alone  in  the  form  of  a connected  and  coherent 
whole,  although  the  internal  appears  in  this  form  when  putrefaction 
has  destroyed  the  medullary  layer.  Hence  we  cannot  consider  the 
retina  except  as  formed  by  the  union  of  two  special  and  distinct  mem- 
branes ; but  We  really  find  on  its  external  face  a very  thin  mem- 
brane^) very  analogous  to  the  serous  membranes,  which  seems  to  us 

(1)  J.  H.  Moeller,  De  tunica  nerved  el  nervo  optico , Halle,  1749.-— B.  S.  Albums, 
De  tunica  quam  vacant  rctinam  ; in  the  Annot.  acad.,  book  iii.,  cap.  xvi.,  Ann.  1756. 

(2)  Several  old  anatomists,  particularly  Winslow,  Cassebohm,  Ferrein,  Lieutaud, 
and  Haller,  whose  arguments  have  been  collected  by  Zinn  ( loc . cit.,  p.  114),  and 
Monro  among  the  moderns  (toc.  cit.,  p.  96),  have  asserted  that  the  retina  passes 
below  the  ciliary  body,  and  that  it  extends  io  the  great  edge  of  the  crystaline  cap- 
sule, to  which  it  is  attached.  But  careful  dissections  have  led  us  to  embrace  the 
contrary  opinion,  which  has  been  supported  by  Morgagni,  Zinn,  and  some  of  their 
predecessors.  Monro  says  that  we  can  prove  that  the  retina  extends  to  the  crys- 
taline humor  : 1st,  by  resting  the  eye  on  the  transparent  cornea,  and  there  making 
a transverse  section  which  includes  all  the  membranes  with  the  vitreous  body  ; 2d, 
by  raising  the  ciliary  body  and  carefully  removing  the  pigment  with  a pair  of 
forceps.  But  in  following  these  two  processes  we  have  always  recognized  that  the 
retina  terminates  evidently  at  the  posterior  extremity  of  the  ciliary  body,  arid  we 
have  even  found  that  the  layer  still  partially  covered  by  the  pigment,  which  extends 
from  the  hyaloid  membrane  to  the  crystaline  capsule,  was  more  transparent  than 
the  retina.  The  eyes  of  the  fetus  are  better  than  those  of  the  adult  to  demonstrate 
that  Monro’s  opinion  is  false,  because  in  them  the  retina  is  more  opaque,  and  the 
external  wall  of  the  canal  of  Petit  is  thinner. 

(3)  Jacob,  Newly  discovered  membrane  in  the  eye;  in  Thomson,  Annals  of  philo- 
sophy, July,  1818,  p.  74;  Phil,  trans.,  1819,  p.  30Ö;  Juurn.  compl.  des  sc.  méd.,  vol. 
xi.,  p.  187. — Jacobson,  Mémoire  sur  une  humeur  peu  connue  de  l’œil,  et  sur  les  ma- 
ladies auxquelles  donnent  quelquefois  lieu  les  changemens  survenus  dans  sa  sécré- 
tion ; in  the  Act.  soc.  reg.  med.  Hafn.,  vol.  vi.  ; and  Bull,  de  la  soc.  méd.  d’ Emu/., 
September,  1822. — G.  Mirault,  Sur  une  hydrophile  puiiiculiirc  au  globe  de  l’œil  ; 
in  the  Archvo.  gén.  de  méd.,  vol.  jj.,  p.  46. 


164 


DESCmi’TIVJi  ANATOMY. 


to  be  the  seat  of  the  ossifications  sometimes  occurring  between  the 
choroid  membrane  and  the  retina. 

§ 2000.  The  retina  is  extended  on  the  vitreous  body,  and  forms 
there  no  fold,  except  in  a small  extent  of  its  posterior  part,  at  some  dis- 
tance from  the  entrance  of  the  optic  nerve,  and  on  its  outer  side. 

There  in  fact  the  membrane  presents,  a fold  which  is  directed 
inward,  a yellow  spot , and  a round  place,  where  it  is  extremely 
thin.(l) 

The  direction  of  this  fold  is  transverse  from  within  outward.  It 
commences  at  some  distance  from,  or  directly  at  the  side  of  the  entrance 
of  the  optic  nerve  by  a small  point,  and  is  terminated  by  a blunt  extre- 
mity. It  is  generally  from  a line  and  a half  to  two  lines  long.  It  is 
commonly  single,  but  sometimes  also  it  is  double.  In  some  subjects  it 
is  deficient.(2)  Home  asserts  even  that  it  is  never  natural,  and  that 
its  formation  depends  on  the  more  intimate  union  in  this  place  between 
the  retina  and  the  hyaloid  membrane.  But  the  error  of  the  English 
anatomist  is  proved  by  the  facts  that  the  fold  is  observed  even  when 
the  connections  between  the  two  membranes  are  unaltered,  and  that 
it  is  much  more  evident  in  youth  than  subsequently. 

The  retina  presents  at  the  same  place  a yellowish  spot  of  the  same 
size,  which  is  darker  in  the  centre  than  on  the  edges.  It  is  generally 
one  line  high,  and  from  one  and  a half  to  two  lines  broad.  But  it 
has  not  the  same  extent  and  degree  of  color  in  every  part,  although 
these  two  peculiarities  are  not  necessarily  connected  with  the  sense  of 
vision. 

The  retina  is  much  thinner  in  this  place  than  in  the  rest  of  its  extent, 
particularly  in  the  centre  of  the  yellow  spot,  where  some  admit  the 
existence  of  a foramen,  while  others,  and  according  to  our  dissections 
more  correctly,  think  that  there  is  a place  entirely  destitute  of  medul 
lary  substance,  of  an  oval  form  and  surrounded  with  smooth  and  dis- 
tinct edges. 

This  thin  place  becomes  very  apparent  only  when  the  vitreous  hu- 
mor is  compressed  to  push  the  fold  outward  and  to  efface  it. 


(1)  Ruzzi,  in  the  Opusc.  suite  scienze  e sullc  aril,  Milan,  vol.  v.,  1784,  and  vol.  vii. 
— Scemmcrring',  Dc  foraminc  centrait  limbo  luleo  cincto  retinœ  humancc  ; in  the 
Comm.  soc.  Gott.,  vol.  xiii.,  1795  -1798. — P.  Michaelis,  Buber  einen  gelben  Fleck  und 
ein  Loch  in  der  Ncrvenhaul  des  menschlichen  Auges  ; in  the  Journal  der  Erfin- 
dungen, part  xv.,  p.  1-17,  1796,  and  cah.  xvii.,  p.  133. — J.  C.  Reil,  Die  Falle , der 
gelbe  Fleck  und  die  durchsichtge  Stelle  in  der  Retzhaut  des  Auges  ; in  Ihc  Archiv. 
Für  die  Physiologie,  vol.  ii.,  p.  468-797.- — E.  Horne,  An  account  of  the  orifice  in  the 
retina  of  the  human  eye  ; in  the  Phil.  Irans.,  1798,  p.  ii. — Exposé  des  résultats  de 
plusieurs  recherches  sur  la  lache  jaune,  le  pli  cl  le  Irou  central  de  la  rétine,  d’après 
deux  mémoires  communiqués  par  Marc  et  Léveille  ; in  the  Mémoires  de  la  soc.  méd. 
d’Em.,  vol.  i.,  1802,  p.  364-397. — J.  M.  Wantzel,  Heber  die  Home’schcn  Entdeckun- 
gen, das  Loch,  die  Falte  und  den  gelben  Fleck  im  Mittelpunkt  der  Retzhaut 
betreffende  ; in  Rosenmuller  and  Isenllamin,  Beiträgen  Jur  die  Zergliederung- 
sfeunst,  Leipsic,  1800,  vol.  i.,  partii-,  p.  204. 

(2)  Reil,  loc.  cit.,  p.  470. 


OF  THE  EYE. 


165 


n humors  or  the  eye. 


a-  VITREOUS  IIUMOR. 

§ 2001  The  posterior  part  of  the  eye  is  occupied  by  the  vitreous 
humor  or  body  ( humor  vitreus , s,  corpus  vilreurn),  which  corresponds 
in  its  situation  to  the  choroid  membrane  and  the  retina.(l) 

This  humor  is  perfectly  transparent,  thin,  and  formed  almost  entirely 
of  water,  which  contains  a small  quantity  of  the  hydrochlorates  and 
the  lactates,  with  still  less  of  albumen  and  soda.  (2)  It  is  contained  in 
a special,  very  thin,  delicate,  transparent  membrane,  which  every 
where  surrounds  it,  and  which  is  termed  the  hyaloid  membrane  ( tunica 
hyaloidea).  This  membrane  sends  internally  numerous  prolongations 
in  the  spaces  of  which  the  liquid  is  contained  as  in  so  many  cellules. 
The  union  of  the  membrane  and  of  the  liquid  which  forms  it,  is  pro- 
perly speaking,  the  vitreous  body. 

This  body  presents  on  its  anterior  face  a slight  cavity  which  is  con- 
nected with  the  crystaline  capsule,  the  posterior  part  of  which  is 
situated  there,  and  adheres  to  it  so  intimately  in  the  normal  state  that 
it  cannot  be  detached  from  it,  at  least  when  the  eye  is  perfectly  fresh, 
without  tearing  the  hyaloid  membrane. 

2002.  Eetween  the  great  edge  of  the  crystaline  capsule  and  the 
anterior  part  of  the  hyaloid  membrane,  a little  behind  the  anterior  edge 
of  this  latter,  is  a thin  layer,  termed  the  ciliary  layer  ( lamina  ciliaris. 
zonula  Zinnii),  which  is  extended  like  a bridge  on  the  most  anterior 
part  of  the  vitreous  body,  in  connection  with  which  it  circumscribes  a 
triangular  space,  the  base  of  which  is  formed  by  the  posterior  part 
of  the  circumference  of  the  crystaline  capsule,  while  the  two  branches 
are  constituted,  one  by  the  layer,  and  the  other,  by  the  most  anterior 
pait  of  the  vitreous  body. 

This  empty  space  surrounds  ihe  crystaline  pmd  the  vitreous  body 
It  is  termed  the  canal  of  Petit  ( canalis , s.  circulas  Petiti)  It  is  easily- 
demonstrated  by  inflating  it  with  air. 


(1)  P.  IVlartegiam  (Nota  obs.de  oculo  humano , Naples,  1814,  p.  19)  admits  be- 

tween the  vitreous  body  and  the  retina  an  empty  space,  in  the  centre  of  which  is  the 
central  artery  of  the  retina,  termed  by  him  the  area  Martcgiani,  in  honor  of  his 
father.  J.  Cloquet  seems  to  admit  the  existence  of  this  deviation,  for  he  says  (De  la 
squelettopée , Paris,  1S19,  p.  72,)  that  the  hyaloid  membrane  is  reflected  on  itself  on 
a level  with  the  enhance  of  the  optic  nerve  into  the  eye,  to  form  a canal  which  passes 
from  behind  forward  directly  through  the  vitreous  body.  He  proposes  to  call  this 
passage  the  hyaloid  canal,  and  asserts  that  it  always  exists  in  man.  P.  T. 

(2)  According  to  Berzelius  (Animal  fiuids  ; in  the  Med.  chir.  Irans.,  vol.  iii.,  p. 
253),  one  hundred  parts  of  the  vitreous  humor  contains  98,40  of  water,  0,16  of  albu- 
men, 1,42  of  the  hydrochlorates  and  lactates,  0,02  of  soda  and  an  animal  matter 
completely  soluble  in  water. 


VOL.  III. 


22 


166 


DESCRIPTIVE  ANATOMY. 


The  ciliary  layer  presents  numerous  fissures,  the  direction  of  which 
is  from  before  backward  and  «from  within  outward,  because  it  corres- 
ponds exactly  to  the  inner  face  of  the  ciliary  body,  which  is  intimately 
united  with  it,  and  the  folds  of  which  are  situated  in  its  depressions. 
Its  external  face  seems  blackish  after  the  ciliary  body  is  removed,  be- 
cause the  pigment  remains  attached  to  it  there.  When  the  canal  of 
Petit  is  inflated,  it  is  raised,  its  grooves  become  more  superficial,  and  its 
external  face  seems  formed  of  rounded  or  triangular  eminences  which 
project  but  slightly  and  are  near  each  other. 

This  layer  is  thicker  than  the  hyaloid  membrane  ; still  as  it  is  united 
with  this  latter,  and  as  the  posterior  edge  of  the  layer  is  continuous 
with  it,  we  have  reason  to  say  that  the  hyaloid  membrane  is  divided 
at  its  anterior  part  into  two  layers,  of  which  the  external  gives  rise  to 
the  ciliary  layer,  while  the  internal  is  adapted  to  the  posterior  face  of 
the  crystaline  capsule. 

Ribes(l)  asserts  that  canals  exist  between  the  ciliary  layer  and  the 
ciliary  body,  which  canals  conduct  the  aqueous  humor  in  the  cham- 
bers of  the  eye,  and  take  it  up  again  from  these  two  cavities.  He 
supports  his  opinion  by  the  dilatation  of  these  pretended  canals  in  an 
eye  affected  with  hydrophthalmia,  and  the  escape  of  the  vitreous  hu- 
mor, when  the  eye  is  suspended  by  the  optic  nerve,  after  removing  the 
transparent  cornea.  But  these  facts  do  not  demonstrate  it  sufficiently. 
The  first  phenomenon  depends  probably  on  the  general  accumulation 
of  serum  in  the  eye,  as  there  is  also  a considerable  collection  of 
serum  between  the  crystaline  lens  and  the  vitreous  body.  We  have 
every  reason  to  think  that  the  second  depended  on  the  pressure  of  the 
vitreous  body  on  a part  which  ought  to  yield  more  easily  after  cutting 
the  transparent  cornea. 


III.  CRYSTALINE  LENS. 

§ 2003.  The  crystaline  lens  ( lens  crislallina)(2)  is  a soft,  rounded 
body,  perfectly  transparent  in  the  normal  state,  the  breadth  and  height 
of  which  are  almost  double  its  thickness,  and  the  posterior  face  of 
which  is  much  more  convex  than  the  anterior  ; at  least  an  inverse 
relation  between  its  two  faces  rarely  exists,  and  they  are  more  fre- 
quently similar.  The  posterior  face  is  generally  a segment  of  a sphere 
about  from  six  to  nine  lines  in  diameter,  while  the  anterior  is  a segment 
of  a sphere  about  five  lines  in  diameter. 


(1)  Mém.  de  la  soc.  mtd.  d’émul.,  vol.  viii.,  p.  622-624. 

(21  A.  F.  Walter,  De  lente  cristallina  oculi  humani,  Leipsic,  1712. — Petit,  Mémoire 
sur  le  cristallin  de  l'œil  de  l'homme , des  animaux  à quatre  pieds , des  oiseaux  et  des 
poissons  ; in  the  Mém.  de  Paris , 1730,  p.  4-33. — S.  G.  Sättig,  De  lentis  crystallines 
structura  fibrosâ,  Halle,  1794. — B.  F.  Bacrcns,  Diss.  sistens  lentis  crystallina : mono- 
graphiam,  1819.— Leiblcin,  Bemerkungen  über  das  System  der  Krystallinsc  bey 
Saughthieren  und  Vögeln,  Wurzburg.  1821. 


OF  THE  EYE 


167 


The  thickness  and  the  convexity  of  the  crystaline  lens  are  not  al- 
ways in  the  same  proportion,  as  there  is  no  constant  relation  between 
these  two  qualities  and  the  breadth  and  height  of  the  lens. 

The  crystaline  lenses  of  the  two  eyes  in  the  same  man  sometimes 
differ  very  much  in  form 

This  body  is  situated  before  the  vitreous  body,  the  concave  anterior 
face  of  which  receives  its  posterior  face,  below  the  ciliary  body,  the  in- 
ternal face  of  which  is  partly  attached  to  its  great  edge,  It  is  situated 
behind  the  iris,  with  which  it  is  not  connected. 

It  however  is  not  loose.  A thin  but  solid  membrane  which  is  trans- 
parent and  much  thicker  than  that  of  the  vitreous  body  exactly  en- 
velops it  in  every  pavt.(l)  This  membrane,  termed  the  crystaline 
capsule  ( capsula  cristallina),  is  the  medium  of  connection  between  the 
crystaline  lens  and  the  adjacent  parts. 

The  crystaline  lens  is  loose  in  its  capsule.  It  is  at  most  attached 
only  by  extremely  minute  vessels,  which  are  detached  from  this  mem- 
brane and  enter  its  substance. 

Between  it  and  the  capsular  membrane  is  a transparent  and  very 
thin  fluid,  termed  the  humor  of  Morgagni  (liquor  Morgagnii)  .(2) 

§ 2004.  The  crystaline  lens  is  formed  of  two  substances,  one  ex- 
ternal and  soft,  the  other  internal  and  harder.  These  two  substances 
blend  together  imperceptibly.  The  first  is  termed  the  cortical  layer , 
and  the  second  the  nucleus.  The  cortical  substance  can  be  easily 
separated  from  the  nucleus  by  crushing  it  between  the  fingers. 

A special  process  is  necessary  to  demonstrate  this  texture  : but 
when  the  most  complex  means  are  emploj'ed,  the  crystaline  lens  is 
proved  to  be  much  more  complicated  than  it  seems  at  first  view,  and 
it  may  constantly  be  reduced  into  a certain  number  of  parts. (3) 

In  fact  by  maceration  and  by  the  action  of  acids  this  body  is  divided 
in  its  whole  extent  from  before  backward  into  several  triangular  seg- 
ments, the  summits  of  which  are  turned  inward  and  the  bases  outward, 
and  which  unite  in  the  centre  of  the  lens.  Besides  each  segment  also 
divides  into  numerous  small  laminæ,  which  are  situated  one  above  an- 
other from  without  inward,  and  which  cover  each  other  like  the  coats 
of  an  onion. 

These  layers  are  reflected  from  before  backward  on  the  outer  edge 
of  the  crystaline  lens,  in  the  centre  of  which  they  accordingly  termi- 
nate by  two  points,  an  anterior  and  a posterior. 

(1)  Petit,  De  la  capsule  du  cristallin  ; in  the  Mém.  de  Paris , 1730,  p.  622-643. 

(2)  Graefe,  Ueber  die  Bestimmung  der  Morgagnischen  Feuchtigkeit  der  Lin- 
senkapsel und  des  Faltenkranzes  ; in  Reil,  Archiv,  für  die  Physiologie,  vol.  ix.,  p, 
225-236,  and  in  Abhandlungen  der  Erlanger  Soc.,  vol.  i.,  p.  309-396. 

(3)  A.  Leeuwenhoek,  De  formatione  humoris  crystalline  in  variis  animalibus,  de 
substantia  fibrosa  quæ  in  oculo  apparct,  &c.  ; in  the  Arc.  nat.  detect.,  Delft,  1695,  p. 
70. — Morgagni,  in  the  Epist.  anat.,  A.  30,  31,  32,  33.— Sättig-,  De  lentis  crystallina: 
structura  fibrosa,  Halle,  1793. — Young,  in  the  Phil.  Irans.,  1793. — Monro,  On  the 
structure  of  the  body  of  the  crystaline  lens,  and  whether  the  fibres  which  enter  into 
its  composition  are  muscular  ; loc.  cit.,  p.  85. 


168 


DESCRIPTIVE  ANATOMY. 


Their  anterior  half  is  often  detached  from  i he  posterior,  and  the 
whole  crystalinc  lens  seems  more  or  less  evidently  divided  into  an 
anterior  and  a posterior  half  by  a fissure  which  extends  from  the  cir- 
cumference to  the  centre. 

The  layers  which  compose  the  crystalinc  lens  are  united  by  fibres 
which  extend  from  one  to  another.  They  are  likewise  composed  of 
fibres,  the  direction  of  which  is  parallel  to  their  proper  longitudinal 
diameter.  These  fibres  consequently  commence  at  the  centre  of  the 
crystaline  lens.  Thus  the  tissue  of  the  crystalinc  lens  is  lamellar  and 
fibrous.(l) 

Between  these  layers  is  a diaphanous  humor,  more  abundant  on  the 
outside  than  on  the  inside,  which  seems  like  that  existing  between  the 
lens  and  its  capsule. 

The  segments  of  the  crystaline  lens  in  respect  to  their  thickness 
and  their  lamellar  texture,  are  more  distinct  on  its  outer  than  on  its 
inner  side.  The  fibrous  texture  is  more  evident  in  the  inner  part. 

§ 2005.  The  crystalinc  lens  almost  entirely  dissolves  in  water,  ex 
cepting  a small  quantity  of  a transparent  and  insoluble  membranous 
substance.  Berzelius  has  found  in  it  of  one  hundred  parts:  of  water, 
58.0  ; of  a peculiar  substance,  35.9  ; of  hydrochlorates,  lactates,  and 
animal  matter,  all  soluble  in  alcohol,  2.4  ; of  animal  matter,  soluble 
only  in  water,  with  some  phosphates,  1.3;  of  insoluble  membranous 
residue,  2.4. (2) 

It  is  particularly  worthy  of  notice  that,  excepting  the  color,  the  pe- 
culiar substance  which  is  coagulated  by  heat  is  perfectly  similar  in 
chemical  composition  to  the  coloring  matter  of  the  blood.  It  contains 
a little  iron,  while  there  is  much  carbon  and  iron  in  the  pigment.  The 
blood  then  seems  to  be  decomposed,  as  the  aqueous  and  vitreous  hu- 
mors contain  only  the  water  which  contributed  to  form  it.  Hence  why 
these  two  humors  do  not  coagulate. 

§ 2006.  The  crystaline  ccupsulc  receives  blood  from  the  central  artery 
of  the  retina  and  the -vessels  of  the  ciliary  body. (3) 

The  central  artery  of  the  retina  is  distributed  in  great  part  by  its 
anterior  branches  on  the  posterior  face  of  the  capsule,  for  its  last  rami- 
fications on  arriving  at  the  anterior  edge  of  the  vitreous  body  are  re- 
flected from  without  inward,  and  converge  towards  the  centre  of  this 
face  ; but  there  are  also  several  small  ones  which  pass  on  the  ex- 
ternal edge  of  the  capsule  and  go  on  its  anterior  face. 

The  arteries  which  arise  from  the  anterior  edge  of  the  ciliary  body 
go  exclusively  on  the  anterior  face  of  the  crystaline  capsule,  and  anas 

(1)  Berzelius  supposes,  but  wrongly,  that  it  also  includes  a membrane  divided  into 

several  compartments  by  internal  septa,  like  those  of  the  vitreous  body  ( Djurkemi , 
vol.  ii.,  p.  212).  Finally,  he  observes,  and  justly,  that  this  body  cannot  be  referred 
to  the  class  of  fibrous  organs,  as  has  been  done  to  a certain  extent  by  Mayer  ( lieber 
Histologie,  p.  13),  and  by  Heusingcr  unrestrictedly  {Histologie,  part  i,;  p,  42),  since  it 
is  entirely  soluble  in  water.  F.  T. 

(2)  Loc.  cil.,  p.  254. 

(3)  J.  G Walter,  De  venir  oçxtfi  cl  artériel  centraii  rclince,  Berlin,  1T78. 


OF  THE  EVE 


1G9 


tomose  there  with  the  ramifications  of  the  central  artery  of  the  retina. 
In  the  fetus  they  send  off  from  behind  forward  numerous  ramuscules, 
which  are  distributed  on  the  posterior  face  of  the  pupillary  membrane. 

The  vessels  of  the  crystaline  capsule  and  those  of  the  pupillary 
membrane  always  correspond  remarkably  in  regard  to  their  arrange- 
ment and  developmental ) 

Finally  the  arteries  of  the  capsule,  especially  those  which  arise  from 
the  central  artery  of  the  retina,  send  several  very  minute  twigs  to  the 
lens  which  are  distributed  between  its  laminæ,  so  that  the  latter  are 
not  nourished,  at  least  entirely,  by  absorbing  the  liquid  which  sur- 
rounds them. 

Veins  have  not  yet  been  strictly  demonstrated  in  the  crystaline  cap- 
sule, although  they  are  known  to  proceed  on  its  posterior  face.  The 
latter  empty  into  the  veins  of  the  choroid  membrane,  with  which  they 
open  on  the  external  face  of  the  ciliary  lamina. (2) 

Farther,  in  the  normal  state  there  is  no  red  blood  in  the  crystaline 
lens  or  in  the  vitreous  body. 

We  have  not  as  yet  discovered  nerves  in  the  crystaline  lens  nor  in 
its  capsule, 

B.  AQUEOUS  HUMOR. 

§ 2007.  The  aqueous  humor  of  the  eye  ( humor  aqueus)  is  a per- 
fectly clear  and  transparent  fluid  which  fills  the  two  chambers.  It  is 
composed  almost  entirely  of  water, (3)  and  is  formed  very  rapidly. 


ARTICLE  THIRD 

MUSCLES  OF  THE  EVE. 

§ 2008.  The  eye  is  moved  by  six  muscles. (4)  Five  of  them  arise 

from  the  floor  of  the  orbit  ; the  sixth  comes  from  the  lower  part  of  its 
anterior  circumference.  They  surround  the  sclerotica,  to  which  they 
are  attached  and  blend  with  it. (5) 

(1)  Hunter,  in  the  Med.  commentaries , London,  1762,  p.  63,  note. 

(2)  Walter,  loc.  cit.,  p.  28,  29. 

(3)  Berzelius  ( Djurkemi,  vol.  ii.,  p,  208)  has  found,  in  one  hundred  parte,  98.10  of 
water;  some  marks  of  albumen;  1.16  of  hydrochlorates  and  lactates;  and  0.75  oi 
animal  substance,  soluble  only  in  water. 

(4)  C.  Bell,  Recherches  sur  les  mouvemens  de  l’œil  et  sur  les  usages  des  muscles 
et  des  nerfs  renfermes  dans  l’orbite  ; in  the  Archiv,  sén,  de  méd.,  vol  vi , n 250 
and  445. 

(5)  The  aponeuroses  which  terminate  them  have  been  considered,  but  wrongly,  as 
a special  membrane  between  the  conjunctiva  and  sclerotica.  (É.  Home  and  P 
Smith,  Philos ; irons.,  1795,  no,  i.,  p.  1Î,  and  no.  xii.,  p,  262.) 


170 


DESCRIPTIVE  ANATOMY 


They  are  divided  according  to  their  direction  into  straight  and 
oblique.  The  first  are  four  in  number  There  are  two  oblique  mus- 
cles. 


I STRAIGHT  MUSCLES. 

§ 2009.  The  straight  muscles  of  the  eye  (M.  recti  Irnlbi  oculi ) are 
the  superior , the  internal,  the  external,  and  the  inferior  ; but  beside 
these  names,  founded  on  the  changes  they  cause  in  the  situation  of  the 
globe  of  the  eye  when  they  contract,  they  have  received  others  also, 
drawn  from  the  expression  they  give  to  the  countenance,  and  from 
the  state  of  the  mind  which  their  action  designates. 

Their  common  character,  is  that  they  all  arise  from  the  floor  of  the 
orbit  by  a short  and  thin  tendon,  and  are  attached  to  the  anterior  part 
of  the  circumference  of  the  sclerotica  by  another  thin  but  broad  tendon. 

I.  RECTUS  SUPERIOR. 

§ 2010.  The  recites  superior  muscle  (M.  rectus  oculi  superior,  s, 
attollens,  s.  superbus),  arises  from  the  periosteum  of  the  orbit,  between 
the  optic  foramen  and  the  upper  sphenoidal  fissure,  between  the  upper 
part  of  the  optic  foramen  and  the  sheath  of  the  optic  nerve,  directly 
below  the  levator  palpebræ  superioris  muscle.  It  goes  forward,  rest- 
ing on  the  upper  part  of  the  globe  of  the  eye,  becomes  broader  and 
thicker  from  behind  forward,  and  is  attached  by  a broad  but  thin 
tendon,  to  the  sclerotica  alone,  two  lines  above  the  transparent  cornea. 

It  is  the  second  in  size  among  the  straight  muscles  of  the  eye.  It 
is  a little  shorter  but  much  thinner  than  the  following  muscle. 

It  raises  the  eye. 

II.  COMMON  TENDON  OF  THE  OTHER  THREE  STRAIGHT  MUSCLES  OF  THE  EVE. 

§ 201 1 . The  other  three  straight  muscles  of  the  eye  arise  partly  by  a 
common  tendon,  or  from  a ligament  which  extends  from  the  inner  ex- 
tremity of  the  sphenoidal  fissure,  to  two  or  three  lines  before  this  point 

III.  RECTUS  EXTERNUS. 

§ 2012.  The  rectus  externus  muscle  (M.  oculi  rectus  externus,  s.  ab 
duccns,  s.  indignatorius ) arises  by  two  heads.  The  lower,  the  larger, 
comes  from  the  external  face  of  the  common  tendon,  where  it  adheres 
very  intimately  to  the  tendon  of  the  rectus  inferior  muscle.  The  up- 
per is  much  smaller,  and  is  blended  with  the  tendon  of  the  rectus 
superior  muscle,  arises  from  the  portion  of  the  sphenoid  bone  comprised 
between  the  optic  foramen  and  the  commencement  of  the  sphenoidal 
fissure.  Hence,  the  muscle  proceeds  along  the  centre  of  the  external 


OF  THE  EYE, 


171 


wall  of  the  orbit,  situated  on  the  periosteum,  and  is  attached  by  a thin 
tendon  to  the  outer  part  of  the  edge  of  the  sclerotica,  some  lines  from 
the  edge  of  the  transparent  cornea.  It  is  broader  at  its  centre  than  in 
the  rest  of  its  course,  and  is  much  flatter  and  thinner  from  without  in- 
ward than  from  above  downward. 

It  is  the  largest,  and  particularly  the  thickest  of  the  straight  muscles 
of  the  eye  : it  is  a little  shorter,  but  infinitely  thicker  than  the  obliquus 
superior  muscle. 

It  carries  the  eye  outward,  and  acts  when  looking  to  the  outside. 

IV.  RECTUS  INFERIOR. 

2013.  The  rectus  inferior  or  the  depressor  oculi  muscle  (J\I.  rectus 
oculi  inferior , s.  deprimens,  s.  Iiumilis),  unites  with  the  lower  head  of 
the  rectus  externus  and  rectus  internus  muscles,  arises  from  the  com- 
mon tendon,  and  never  comes  from  the  sheath  of  theoptic  nerve. 
It  goes  from  before  backward,  and  from  above  downward  under  the 
optic  nerve,  and  is  attached  to  the  sclerotica. 

It  is  the  third  in  size  of  the  recti  muscles  of  the  eye,  but  it  is  thinner 
and  shorter  than  the  rectus  internus  muscle. 

It  depresses  the  eye. 

V.  RECTUS  INTERNUS. 

§ 2014.  The  rectus  internus  muscle  (JMT.  rectus  oculi  internus , s.  ad- 
ducens , s.  amatorius , s.  bibitorius)  arises  by  two  heads.  The  inferior 
or  external  comes  from  the  upper  and  internal  part  of  the  common 
tendon.  The  superior  or  internal  is  the  larger,  and  arises  from  the 
inner  part  of  the  sheath  of  the  optic  nerve.  This  latter  blends  with 
the  origins  of  the  rectus  superior  and  the  levator  palpebræ  superioris 
muscles.  Thence  the  muscle  goes  inward  and  forward,  along  the 
inner  wall  of  the  orbit,  from  which  it  is  separated  by  a layer  of  fat.  Its 
short  and  thin  tendon  is  attached  to  the  inner  part  of  the  circumference 
of  the  sclerotica. 

It  is  the  shortest  of  the  four  recti  muscles,  but  it  is  thicker  than  the 
superior  and  inferior. 

It  draws  the  eye  inward. 

II.  OBLIQ.UE  MUSCLES. 

' § 2015.  The  oblique  muscles  of  the  eye  (JVf.  obliqui  bulbi  oculi)  are 

distinguished  into  superior  and  inferior.  They  turn  the  globe  of  the 
eye  on  its  longitudinal  axis  in  opposite  directions. 

I.  OBLIQUUS  SUPERIOR. 

§ 2016.  The  obliquus  superior  muscle,  grand  oblique , Ch.  (JVf, 
oculi  obliquus  superior , s,  longus , s.  irochharis , pafhetims),  arises  from 


172 


DESCRIPTIVE  ANATOMY. 


the  posterior  part  of  ihc  inner  face  of  the  internal  wall  of  the  orbit, 
belorc  the  optic  foramen,  and  also  arises  from  the  sheath  of  the  optic 
nerve  by  a thin  and  short  tendon  Thence  it  goes  upward  and  forward 
along  the  upper  edge  of  the  internal  wall  of  the  orbit,  and  becomes 
near  its  anterior  extremity,  a long  rounded  tendon. 

This  tendon  immediately  enters  into  a small  cartilaginous  layei 
about  two  lines  long  and  broad,  which  is  reflected  on  itself,  and  thus 
represents  a semicanal,  open  upward,  forward,  and  backward,  and  forms 
a pulley,  the  anterior  edge  of  which  becomes  a pointed  prominence, 
while  the  upper  edges  arc  attached  by  ligamentous  fibres  to  the  upper 
part  of  the  internal  wall  of  the  orbit. 

The  tendon  is  kept  in  this  pully  by  a loose  and  movable  cellular 
tissue  Its  direction  changes,  so  that  on  emerging  it  descends  horn 
before  backward,  and  from  within  outward.  It  then  becomes  broader, 
and  is  attached  to  the  inner  and  upper  part  of  the  sclerotica,  on  the 
inside  of  the  tendon  of  the  rectus  superior  muscle  w flieh  partially 
covers  it. 

This  muscle  is  the  longest  and  thinnest  muscle  of  the  eye. 

It  draws  the  eye  forward,  inward,  and  upward 

Sometimes,  but  rarely,  it  is  more  or  less  perfectly  double. 

II.  OBLIQUUS  INFEKÏOK. 

2017.  The  obliquus  inferior  muscle,  petti  oblique , Ch  (M.  oculi 
obliquus  inferior ),  the  shortest  muscle  of  the  eye,  differs  from  the  other 
muscles  in  its  origin  and  direction.  It  arises  by  a short  tendon  from 
the  inner  extremity  of  the  lower  edge  of  the  orbit,  goes  upward  and 
outward,  then  becomes  a short  and  broad  tendon,  which  ascends  below 
the  anterior  part  of  the  rectus  extemus  muscle,  and  between  the 
muscle  and  the  globe  of  the  eye,  and  is  attached  to  the  sclerotica,  some 
distance  behind  the  tendons  of  the  recti  muscles,  between  that  of  the 
extemus  and  that  of  the  superior. 

It  rotates  the  eye  on  its  axis,  first  outward,  then  downward,  and 
finally  inward.  It  also  draws  the  eye  a little  forward. 

A It  T I V LE  FOURT II. 

FUNCTIONS  OF  THE  EYE. 

§2018.  The  eye  represents  ah  optical  instrumental)  composed  of 
several  transparent  substances  situated  successively  horn  without  in- 
ti) G.  G.  Ploucqùct,  Dits,  sislens  momenta  quudam  physiologica  circa  visum, 
Tubingen,  1797. — J.  Campbell,  iu  Thomson,  Annals  of  philosophy,  vol.  x.  p.  1 7—29.— 
Dunglison,  ibid.,  no.  GO.  p.  432.— T.  Young,  Of  the  mechanism  of  the  eye;  in  the 
Phil.  Irans.,  1801,  p.  81. — E.  Hall,  iu  the  Journal  of  sciences  and  the  arts , no.  x.  p. 
249-257.— A.  Horn,  The  scat  of  vision  determined , London,  1815. — M.  T.  Muhlibach, 
InmdsUio  de  visûs  sensu,  Vienna,  1816..— J.  Purkinje,  Beytrage  sur  Kenntniss  des 
lichens  in  siihjehtircr  Hinsicht,  Prague;  1810  Troxler,  in  Himly,  Ophthal  Bibi, 


ÖF  THE  EVE. 


173 


ward,  which  differ  in  density,  although  in  all,  this  is  greater  than  that 
of  the  atmosphere.  The  rays  of  light  which  enter  it  gradually  con- 
verge on- passing  through  it,  so  as  to  form  but  one  fasciculus,  which 
paints  the  image  of  the  object  at  the  bottom  of  the  eye  on  the  retina. 
The  impression  upon  this  membrane  extends  to  the  brain  along  the 
optic  nerve,  and  there  produces' the  sensation  of  sight. 

The  transparency  of  the  centres  which  form  the  eye,  the  sensibility 
of  the  retina,  and  the  conducting  power  in  the  optic  nerve,  are  then 
the  principal  conditions  necessary  to  sight.  The  opacity  of  one  or 
several  of  the  centres  which  concur  to  form  the  eye,  the  paralysis  of 
the  retina  and  of  the  optic  nerve,  the  alterations  in  the  texture  of  all  these 
parts,  the  abnormal  productions  which  are  developed  within  or  around 
them,  consequently  alter  or  destroy  the  sense  of  vision.  The  globular 
form  of  the  eye  favors  the  refraction  of  rays  of  light.  Hence,  why  the 
general  form  of  the  eye  and  of  its  different  parts  very  much  influence 
the  distance  at  which  objects  are  seen  clearly.  When  the  eye  is  very 
convex,  the  rays  of  light  are  forcibly  refracted,  and  we  cannot  discern 
objects  which  are  near  (myopia).  When  the  eye  is  flattened  the  re- 
fraction is.  less,  and  only- distant  objects  are  seen  clearly  ( presbytia , 
presbyopia).  Hence,  why  myopia  belongs  only  to  youth  and  infancy, 
and  presbytia  to  old  age.  The  eye  possesses  also  the  power  of  modify- 
ing its  form,  the  relations  of  its  constituent  parts,  its  situation,  and  its 
direction,  either  to  obtain  a distinct  view  of  objects  situated  at  different 
distances,  in  a ray  of  a certain  breadth,  or  to  see  without  moving  the 
head  or  body,  those  which  occupy  the  different  points  of  a portion  of  a 
surrounding  sphere.  This  last  effect  is  produced  by  the  action  of  the 
six  muscles  of  the  eye.  The  other  depends  on  the  contraction  of  the 
muscles,  partly  on  the  modifications  in  the  secretion  and  excretion  of 
the  humors  of  the  eye,  partly  on  the  action  of  tjie  ciliary  body,  since 
these  three  causes  united  change  the  curve  of  the  transparent  cornea 
and  the  crystaline  lens,  as  also  the  situation  of  this  latter  in  regard  to  the 
cornea  and  the  base  of  the  eye.(l)  The  dark  color  of  the  pigment 
tempers  the  violence  of  the  impression  which  the  light  would  other- 
wise cause  on  the  retina,  which  is  extremely  sensible, (2)  for  this  black 

vol.  i.  p.  21—99. — Meyer,  Das  Auge,  ein  Hohlspiegel  ; in  Deutsches  Archiv  fur  die 
Physiologic,  vol.  v.  p.  54. — M.  G.  Plagge,  Neue  physikalische  Ansicht  des  Sehens: 
ibid.,  vol.  v.  p.  97. — Id.  Neuer  Bcy  trag  zàr  Lehre  von  Sehen:  ibid.,  vol.  vii.  p.  213. — 
E.  E.  Rœdenbeck,  Quœdam  ad  Iheoriam  visus  pertinentia,  Berlin,  1822. 

(1)  Simonoff  has  concluded  from  calculations,  that  it  is  not  necessary  to  suppose 

the  crystaline  lens  displaced,  and  that  the  clearness  of  vision  of  objects  situated  lrom 
two  hundred  and  fifty  millimetres  to  any  distance,  however  great,  depends  only  on 
their  apparent  diameters,  and  on  the  transparency  of  the  air  between.  ( Réfutation 
de  lapretendue  nécessité  mathématique  du  déplacement  du  cristallin  pour  conserver 
constante  la  distance  focale  de  l'œil:  in  the  Journ.  de  physiol,  experirn.,  vol.  iv.  p. 
260.)  F.  T. 

(2)  The  sensibility  of  the  retina  is  extreme  only  in  regard  to  light.  Magendie  has 

determined  that  but  a slight  sensation  is  produced  when  this  membrane  is  touched 
by  a needle,  and  that  even  on  scraping  it,  the  pain  is  but  slight,  and  not  to  be  com- 
pared with  that  caused  by  pricking  the  surface  of  the  eye.  (De  l'influence  de  La 
cinquième  paire  sur  la  nutrition  cl  les  fondions  de  l’œil:  in  the  Journ.  dephys.  expér., 
vol.  iv.  p.  176.)  This  physiologist  lias  also  determined  that  the  section  of  the  two 
nerves  ot  the  fifth  pair  causes  the  loss  of  sight.  F.  T. 

Vol.  Ill  23 


174 


DKSCRIPTJVE  ANATOMS. 


layer  absorbs  a part  of  toe  rays  of  light.  This  is  the  real  function  of 
the  pigment,  since  vision  is  weak  and  imperfect  when  it  has  not  its 
usual  color.  The  iris  also  serves  to  moderate  the  intensity  of  the  light 
which  enters  the  eye,  since  this  membrane  dilates,  and  thus  con- 
tracts the  pupil,  when  the  light  is  very  vivid,  or  when  we  look  at  an 
object  near,  while  it  contracts  and  thus  enlarges  the  pupil,  when  the 
light  is  weak,  or  when  we  look  at  rather  a distant  object. 


ARTICLE  FIFTH. 

DIFFERENCES  IN  THE  EYE  DEPENDING  ON  DEVELOPMENT. 

§ 2019.  The  eye  differs  considerably  at  different  periods  of  life, (1) 
in  respect  to  the  existence,  proportional  volume,  and  form  of  the 
whole  eye  or  of  its  parts. 

The  eye  appears  very  early.  It  is  visible  at  the  fourth  week  of 
pregnancy  as  a black  spot. 

But  at  this  period  the  globe  of  the  eye  is  still  exposed,  for  the  eye- 
lids do  not  exist.  They  begin  to  appear  during  the  tenth  week,  in 
the  form  of  narrow  bursæ,  which  gradually  enlarge.  After  about  the 
twelfth  week  their  edges  touch,  and  they  remain  closed  as  in  sleep 
until  birth. 

The  lachrymal  puncta,  and  generally  all  the  lachrymal  apparatus, 
as  also  the  Meibomian  glands,  are  proportionally  more  developed 
during  the  early  periods  of  life  than  subsequently. 

The  eye  is  proportionally  larger  in  the  early  periods  of  life  than  af- 
terward. The  two  external  membranes,  the  sclerotica,  especially 
its  posterior  part,  and  the  transparent  cornea,  are  proportionally 
thicker.  This  character  belongs  especially  to  the  cornea,  which  is  twice 
as  thick  as  it  is  in  the  adult,  from  a considerable  quantity  of  reddish  se- 
rum existing  between  its  layers,  in  the  full  grown  fetus,  so  that  its  an- 
terior face  is  nearly  plane,  and  the  posterior  touches  the  iris.  It  is  also 
less  transparent  than  subsequently.  In  old  age  it  becomes  planer, 
harder,  denser,  and  more  solid  : we  also  see  developed,  in  old  men,  a 
nebulum,  which  extends  from  the  edge  to  the  centre  ( geronlonoxon , s, 
arcus  senilis),  which  undoubtedly  depends  on  the  slowness  with  which 
the  substance  is  renewed,  whence  the  fluids  have  more  tendency  to 
coagulate  ; this  resembles  those  ossifications  which  supervene  in  old 
age  in  other  parts  of  the  body. 

The  choroid  membrane  also  is  proportionally  thicker,  and  the  black 
pigment  which  covers.it  has  a deeper  tint. 

The  pigment  begins  to  appear  very  early  at-  the  fifth  month  of  preg- 
nancy. But  before  birth  it  is  less  colored  than  in  the  adult  : it  adheres 
less  to  the  choroid  membrane  and  the  iris  : it  does  not  exist  on  the  outer 
face  of  the  first  of  these  two  membranes,  so  that  the  intensity  of  its 

(1)  J.  G.  Brendel,  De  fabric  a oculiin  f&bihus  abortivis  observala,  Gottingen,  1752. 


OF  THE  EVE. 


175 


color  and  even  its  quantity  seems  to  depend  on  the  action  of  the  light. 
In  subjects  al  an  advanced  age,  its  color  changes  like  the  hair,  and  it  is 
lighter,  but  the  cornea  and  crystaline  lens  loose  their  transparency  in 
the  same  proportion.  The  deeper  color  of  the  pigment  in  youth, 
depends  partly  on  the  fact,  that  the  globules  are  nearer  each  other, 
partly  also  on  their  being  blacker  at  this  period.  They  are  also 
softer  in  young  people,  and  hence  they  lose  their  form,  and  are  de- 
tached from  each  other  by  drying.  In  the  full  grown  fetus,  the  white 
cellular  tissue  existing  between  the  vessels  of  the  choroid  membrane, 
contains  no  iron,  while  there  is  much  in  that  , colored  black  found  in  the 
same  place  in  the  adult. (1) 

The  iris  is  one  of  the  parts  of  the  ej'e  which  varies  the  most  at 
different  periods  ; the  greatest  change  is  the  closing  of  the  pupil  by 
the  pupillary  membrane  ( membrana  pvpillaris ),  or  the  membrane  of 
Wachendorff,  in  honor  of  its  discoverer. (2) 

The  external  edge  of  this  membrane  arises  from  the  inner  edge  of 
the  iris.  It  fills  the  whole  pupil,  so  as  to  separate  completely  the  pos- 
terior from  the  anterior  chamber.  It  is  a very  tense,  rather  solid,  but 
very  delicate,  thin,  and  transparent  membrane,  so  that  when  its  blood- 
vessels are  injected,  they  cannot  be  perceived  until  the  eye  is  hardened 
by  immersion  in  alcohol.  It  is  composed  of  two  layers,  the  anterior  of 
which  is  a continuation  of  the  serous  membrane  which  lines  the  an- 
terior face  of  the  iris  ; and  the  posterior  is  very  vascular,  and  is  con- 
tinuous -with  the  posterior  face  of  the  his.  We  have  never  known  it 
to  be  covered  posteriorly  with  a fibrous  mucus,  as  Haller  and  Wachen- 
dorff  assert. 

Some  of  its  arteries  arise  : 

1st.  From  those  which  form  the  inner  circle  of  the  iris  : they  radi- 
ate from  this  circle  towards  the  centre  of  the  pupillary  membrane, 
where  anastomosing  with  the  adjacent  vessels,  and  not  with  those  op- 
posite, they  terminate  and  leave  a small  space  in  the  centre  of  the 
membrane.  They  also  anastomose  with  each  other  frequently  in  their 
course. 

2d.  Other  branches  arise  directly  from  the  long  ciliary  arteries,  pass 
on  the  iris,  and  go  directly  to  the  pupillary  membrane,  where  they 
anastomose  with  the  preceding. 

3d.  Others  still  smaller  arise  from  the  vessels  of  the  anterior  face 
and  from  the  greater  edge  of  the  crystaline  lens,  and  are  distributed 
principally  on  the  posterior  face  of  the  pupillary  membrane. 

(1)  Coli,  in  Mondini,  loc.  cit.,  p.  17. 

(2)  E.  J.  Wachendorff,  in  Comm.  J\or.,  1740.  Hebd.  18.  p.  137. — Haller,  De  nova 
tunica  pupillam  fœtus  clauder.ti  ; in  the  Act.  Upsdl.,  1742,  and  Op.  min.,  vol.  i.  p. 
329.— J.  G.  Rœderer,  Defœtu  perfecta , Strasburg-,  1750,  § xxvi.— B.  S.  Albinus,  De 
membrana  pupillam  Inf  antis  nuper  natiprœcludente  : in  Anrot.,  acad.  1.  i.  cap.  vii. 
— Vicq-d’Azyr,  Sur  la  membrane  pupillaire  du  fœtus  : in  Hist,  de  la  soc.  roy.  de  méd., 
ann.  1777  and  1778,  p.  257. — J.  F.  Blumenbach,  De  oçulis  leucœthiopum  et  motu 
iridis,  Gottingen,  1786. — H.  A.  Wrisberg,  De  membrana  fœtus  pupillari:  in  Non. 
comm.  Gott.,  vol.  ii.  and  in  Syllog.  comm.  I. — Edwards,  Sur  la  structure  de  l'œil  .-  in  the 
Bull,  delà  soc.  philomatique,  1814,  p.  21. — J.  Cloquet,  Mémoire  sur  la  membrane 
pupillaire  et  sur  la  formation  du  petit  cercle  artériel  de  Viris,  Paris,  1818.— Portai, 
Sur  la  membrane  pupillaire  : in  Mémoires  du  Museum,  vol;  iv.  p.  457. 


176 


DESCRIPTIVE  ANATOMY. 


Veins  have  not  been  demonstrated  with  certainty  on  the  posterior 
face  of  the  pupillary  membrane. 

The  pupillary  membrane  passes  through  several  periods  of  develop- 
ment. Its  primitive  form  is  not  known,  nor  the  manner  in  which  it  is 
produced,  nor  the  period  of  its  first  appearance. 

According  to  Wrisberg  it  is  not  perceived  distinctly  before  the  third 
month  of  pregnancy.  It  is  gelatinous  and  destitute  of  vessels  until  the 
fifth  month,  but  at  this  period  it  becomes  • firmer  and  vessels  are  de- 
veloped in  it.  Perhaps,  however,  in  the  early  periods  of  life  it  is 
greater  in  proportion  to  the  rest  of  the  iris,  for  the  development  of  the 
latter  membrane  begins  at  its  external  edge. 

It  is  most  evident  at  the  seventh  month  of  pregnancy.  It  begins  to 
disappear  at  the  eighth  month  from  the  centre  to  the  edge,  that  is,  from 
the  portion  which  has  no  vessels.  In  the  full-grown  fetus  the  only 
vestiges  of  this  membrane  are  some  small  loose  flocculæ  attached  to 
the  edge  of  the  pupil. 

It  generalty  disappears  much  sooner  in  animals  bom  with  the  faculty 
of  seeing  than  in  those  born  blind  ; it  continues  in  these  latter  also  as 
long  as  the  eyelids  remain  closed.(l)  The  vessels  are  not  destroyed 
with  it.  They  contract  from  the  centre  toward  the  circumference  ; 
their  arches  diminish,  and  they  are  finally  adapted  to  the  inner  edge  of 
the  ins,  where  they  form  the  small  arterial  circle,  which  does  not  exist 
so  long  as  the  pupillary  membrane  continues. (2) 

Although  this  membrane  perfectly  separates  the  two  chambers,  each 
cavity  constantly  incloses  an  aqueous  humor,  which  does  not  exist  in 
the  posterior  alone  as  Edwards(3)  and  Ribes(4)  assert.  We  have 
demonstrated  this  perfectly, (5)  and  Cloquet  after  us. (6) 

A very  curious  periodical  difference  of  the  iris  is  a want  of  continuity 
of  its  circle,  which  is  observed  during  the  early  periods  of  pregnancy, 
and  which  is  very  sensible  at  its  inner  part  until  about  the  seventh  week. 

The  retina  is  much  thicker  in  the  early  periods  of  life  than  after- 
ward. This  thickness  does  not  depend  on  the  greater  development  of 
its  inner  layer  ; and  so  far  from  the  medullary  layer  being  propor- 
tionally thinner  at  this  period,  so  far  from  possessing  at  that  time  less 
medullary  matter,  as  has  been  assorted, (7)  this  substance  on  the  con- 
trary is  more  abundant,  and  hence  the  increase  of  thickness  presented 

(1)  Meckel,  lieber  die  Dauer  der  pupülar  Membran  ; in  the  Deutsches  Archiv, 
für  die  Physiologie , vol.  i.,  p.  430  ; vol.  ii..  p.  136. 

(2) .  In  demonstrating-  this  fact  J.  Cloquet  has  verified  a conjecture  of  Blumen- 
bach : E jusque  (memijranœ  puvillaris)  vasorum  elliplici  arcus  scnsim  scnsimquc 
reirahuntur,  tuneque,  ni  graviter  fall.or,  annulum  iridis  inlcriorcm  cjjiciunt,  cujus 
ccrte  ante  eum  terminum  nullum  in  Jcetuum  oculis  vestigium  reperire  potui.  (Inst, 
physiol.,  1787,  p.  208.) 

SLoc.  cit. 

Loc.  cit. 

(5)  Loc.  cit. 

(6)  Loc.  cit. 

(7)  Brandis,  Pathologic , Hamburgh,  1808,  p.  241. 


OF  THE  ETE. 


177 


by  the  membrane.  In  old  men  the  retina  becomes  extremely  thin,  but 
also  more  firm  and  resisting. 

We  already  perceive  its  fold  in  the  sixth  month  of  pregnancy,  and 
even  in  the  full-grown  fetus  it  is  greater  than  in  the  adult.  The  thin 
place  is  visible,  but  the  yellow  tint  does  not  appear  till  some  time  after 
birth.  It  gradually  becomes  more  intense,  but  turns  paler  as  age  ad- 
vances. It  would  seem  that  the  fold  diminished  regularly  and  finally  dis- 
appeared entirely.  The  less  marked  development  in  this  region  in  old 
men  is  about  in  a direct  ratio  with  the  loss  of  transparency  which  gra- 
dually takes  place  in  the  cornea.  The  aqueous  humor  is  turbid  in 
the  fetus.  It  becomes  perfectly  transparent  during  the  first  few  weeks 
after  birth. 

The  crystaline  lens  also  is  much  more  convex  in  the  fetus  and  in 
infancy  than  in  the  adult.  At  first  it  projects  through  the  pupil,  and 
thus  pushes  the  iris  before  it,  so  that  it  is  separated  from  the  transpa- 
rent cornea  only  by  this  membrane,  being  situated  in  its  special  groove. 
In  this  respect  and  in  the  absence  of  the  eyelids,  the  eye  of  the  fetus 
resembles  that  of  fishes. 

This  arrangement,  added  to  the  great  thickness  of  the  transparent 
cornea,  causes  the  chambers  to  be  smaller  and  the  aqueous  humor  less 
abundant  than  in  the  adult.  All  the  humors,  however,  excepting  the 
aqueous,  are  more  abundant  in  youth  than  subsequently,  whence  it 
follows  that  the  whole  eye,  and  particularly  the  cornea,  projects  more, 
while  as  age  advances,  the  eye  slightly  collapses  and  the  transparent 
cornea  particularly  flattens. 

As  age  advances  the  crystaline  lens  assumes  more  consistence,  and 
also  becomes  yellowish  on  tearing  the  centre,  so  that  this  tint  is  found 
generally  in  persons  in  advanced  life.  The  same  is  true  of  the  humor 
of  Morgagni.  At  the  same  time  this  humor  and  that  which  fills  the 
two  chambers  are  slightly  turbid,  which  is  sometimes  the  case  also 
with  the  vitreous  humor. 


ARTICLE  SIXTH. 

EYE  IN  THE  ABNORMAL  STATE. 


§ 2020.  The  situation  of  the  eye  exposing  it  to  the  action  of  all 
external  causes  of  injury,  and  its  extreme  sensibility  rendering  it  liable 
to  be  diseased  from  the  influence  of  these  causes,  or  to  participate  in 
the  affections  of  other  parts  of  the  body,  and  finally  its  very  complex 
structure,  singularly  multiply  the  number  of  the  anomalies  it  may  pre- 
sent ; these  anomalies  are  more  easily  perceived  even  during  life  than  in 


178 


DESORITTIVE  ANATOMY. 


most  other  organs,  on  account  of  its  situation  and  the  transparency  of 
its  parts.(l) 


I.  DEVIATIONS  OF  FORMATION. 


§ 2021.  Here,  as  in  other  organs  of  the  body,  the  primitive  devia- 
tions of  formation  are  the  most  remarkable  in  respect  to  the  conse- 
quences deduced  from  them  in  regard  to  the  general  theory  of  organi- 
zation. 


A.  PRIMITIVE  DEVIATIONS  OF  FORMATION. 

§ 2022.  I.  The  primitive  deviations  of  formation  in  respect  to  quan- 
tity consist  essentially  in  too  slight  an  action  of  the  formative  power. 
They  are  : 

1st.  Deviations  in  formation  from  defect  in  development.  Here  we 
may  mention  : 

a.  The  absence  of  the  eye  or  of  some  of  its  parts.  Here,  as  in  the 
other  organs,  the  conditions  are  not  always  exactly  the  same.  In  one 
case  observed  by  Malacarne,(2)  the  optic  beds  and  nerves,  the  common 
and  the  superior  motor  nerves,  the  globe  of  the  eye,  its  muscles,  the 
caruncula  lachrymalis,  and  the  optic  foramina,  were  all  deficient.  The 
globe  of  the  eye  was  replaced  by  a hard  mass.  The  lachrymal  appa- 
ratus and  the  eyelids  were  perfectly  developed. 

In  another  case(3)  the  globe  of  the  eye  and  the  optic  nerve  as  far 
as  its  bed  and  the  optic  foramen  were  deficient,  but  the  accessory 
nerves  and  the  lachrymal  gland  were  present. 

b.  Smallness  of  the  organ. 

(1)  Beside  the  treatises  on  the  diseases  of  the  eyes,  among'  which  we  may  mention 
particularly  those  of  Maître  Jean,  Taylor,  Janin,  Rowley,  Beer,  Scarpa,  Schmidt, 
and  Himly,  beside  also  the  works  already  mentioned,  because  their  authors  have 
examined  it  both  in  the  state  of  health  and  that  of  disease,  we  shall  mention,  on  the 
pathological  anatomy  of  this  organ,  the  following:  J.  C.  Sybel,  Diss.  de  quibusdam 
materiœ  et  formas  oculi  aberrationibus  a statu  normali , Halle,  1798. — J.  Wardrop, 
Essays  on  the  morbid  anatomy  of  the  human  eye , London,  1818. — Farre,  A treatise 
on  some  'practical  points  relating  to  the  diseases  of  the  eye , by  the  late  Conningham 
Saunders,  to  which  are  added , &c.,  London,  1816. — Demours,  Traité  des  maladies 
des  yeux,  Paris,  1818. — Helling,  Praktisches  Handbuch  der  Augenkrankheiten,  Ber- 
lin, 1721. — Baratta,  Osservazioni  pratiche  suite  principali  malatti  e degli  occhi , 
Milan,  1821. — L.  M.  Mejra,  Tratado  tcorico  y practico  sobre  las  infermidades  de  los 
ojos,  Orea,  1820. — B.  Travers,  Synopsis  of  the  diseases  of  the  eye,  London,  1820. — 
J.  Vetch,  A practical  treatise  on  the  diseases  of  the  eye,  London,  1820. — Consult  also, 
on  the  pathological  anatomy  of  the  lachrymal  organ,  J.  A.  Schmidt,  Ueber  die 
Krankheiten  des  Thranenorgans,  Vienna,  1803. — C.  H.  Tode,  Des  maladies  de  la 
glpnde  lacrymale  ; in  the  Mélanges  de  chirurgie  étrangère,  Geneva,  1824,  p.  391. 

(2)  ’Isistemi,  Padua,  1803. 

(3)  Weidele,  in  Himly,  Ophthalmolog.  Bibliothek.,  vol.  iii.,  p.  2,  p.  170. 


OF  THE  EYE, 


179 


c.  The  abnormal  continuance  of  parts  primarily  existing,  particu- 
larly of  the  pupillary  membrane.(l) 

d.  The  adhesion  of  the  two  eyes.  It  is  rather  a general  law  in  this 
case  that  the  eye  formed  by  the  fusion  of  the  two  in  one  is  situated 
directly  on  the  median  line,  and  is  symmetrical  in  its  structure. 

2d.  Deviations  in  formation  or  in  regard  to  quantity  in  an  opposite 
sense  when  the  body  and  head  are  normal,  are  very  rare,  and  perhaps 
have  never  been  observed. 

II.  The  deviations  of  formation  in  respect  to  quality  are  also  rare. 
They  affect  most  frequently  the  form  of  the  iris  and  that  of  the  pupil, 
which  then  is  usually  less  round  and  most  commonly  perpendicular, 
rarely  horizontal.  This  anomaly,  often  peculiar  to  certain  families, 
and  hereditary,  is  always  curious  as  an  analogy  with  animals. (2) 
The  iris  is  rarely  enlarged  so  much  outward  that  the  pupil  does  not 
correspond  to  the  axis  of  the  eye,  being  carried  much  more  inward. (3) 

The  transparent  cornea  is  sometimes  conical  ( staplujloma  conoides ), 
and  at  the  same  time  it  is  more  or  less  thin.  This  state  is  its  greatest 
degree  of  convexity,  whence  this  includes  also  the  greatest  degree  of 
myopia. 

Sometimes  the  cornea  presents  an  opposite  arrangement,  being  not 
sufficiently  convex  or  entirely  plane. 

B.  ACCIDENTAL  DEVIATIONS  OF  FORMATION. 

§ 2023.  The  accidental  deviations  of  formation  are  more  common 
than  the  preceding  and  very  various,  but  they  depend  most  generally 
on  a previous  alteration  in  the  chemical  composition,  and  the  texture 
of  the  parts  is  then  more  or  less  changed.  The  principal  deviations  of 
this  kind  are  : 

1st.  Absence.  Here  we  may  mention  the  loss  of  the  eyelashes  and 
eyebrows,  caused  by  the  destruction  of  their  bulbs,  by  inflammations 
and  ulcerations  of  the  eyelids. 

2d.  Alterations  in  size. 

a.  Smallness.  In  blindness,  the  whole  eye  or  at  least  some  of  its 
parts,  particularly  the  optic  nerve  and  the  retina,  are  often  wasted. 

We  have  found  several  times  in  subjects  who  have  been  blind  for  a 
long  time,  that  the  retina  was  unusually  thin  and  destitute  of  medul- 
lary substance  in  séveral  parts  of  its  extent,  this  substance  existing 
at  intervals. 

When  the  power  of  vision  is  more  or  less  diminished,  the  yellow  spot 
also  returns  to  the  degree  of  color  it  presented  before  the  eye  was 
exposed  to  the  light,  for  in  this  case  its  tint  is  more  or  less  enfeebled. 

(1)  See  our  Randbuch  der  pathologischen  Anatomie , vol.  i.,  p.  396. 

(2)  See  our  Handbuch  der  pathologischen  Anatomie , vol.  ii.,  p.  158. 

(3)  Demours,  tab.  lxiv.,  fig.  1.  , 


löO 


DEâCltlPTIVE  ANATOMT. 


At  tho  samo  time  the  fold  is  more  ov  less  effaced.(l)  Sometimes  in 
subjects  affected  with  amaurosis  the  retina  presents  in  this  place  black 
spots  ;(2)  but  only  the  diseased  eye  undergoes  this  change  ; the  fold 
and  the  spot  are  on  the  contrary  sometimes  more  sensible  in  that  of 
the -healthy  side  ;(3)  the  optic  nerve  is  even  sometimes  larger  than  in 
the  normal  state. (4) 

The  optic  nerve  is  generally  thinner  and  gray  like  horn. 

The  transparent  cornea  sometimes  becomes  much  flatter  after  dis- 
eases of  long  duration  and  excessive  evacuations. 

The  crystaline  lens,  left  in  the  eye  after  separating  it  from  its  cap- 
sule partially  or  wholly,  disappears  very  rapidly.  At  the  end  of  a few 
years  there  is  hardly  a piece  as  large  as  a pin-head.(5) 

b.  Enlargement.  The  eye  sometimes  enlarges  so  mttch  from  dropsy 
( hydrophtlialmus ),  that  it  projects  on  the  outside  of  the  orbit.  This 
dropsy  is  situated  primitively  in  the  vitreous  body  ; but  it  extends  to 
every  part,  so  that  in  some  subjects  we  find  considerable  serum  be- 
tween the  ciystaline  lens  and  the  vitreous  body. (6)  Scarpa  states 
that  dropsy  of  the  posterior  part  of  the  eye  is  usually  attended  with  an 
increased  secretion  out  of  the  vitreous  body,  as  we  have  found  several 
times  on  the  inside  of  the  choroid  membrane  and  of  the  retina  a great 
quantity  of  limpid  serum,  in  which  is  a cord  directed  from  before  back- 
ward, formed  by  the  morbid  alteration  of  the  vitreous  body  and  re- 
tina.(7)  In  this  case  probably  the  serum  came  from  the  serous  mem- 
brane discovered,  by  Jacob. 

A partial  enlargement  of  the  eye,  often  met  with,  forms  staphy- 
loma,(8)  a greater  or  less  thickening  of  the  transparent  cornea,  which 
causes  the  falling  of  this  membrane,  attended  with  its  opacity,  and 
depends  on  a previous  inflammation  situated  in  it.  In  this  case  the 
cornea  generally  adheres  to  the  iris.  The  increase  with  the  thinness 
of  the  sclerotica,  which  is  much  rarer  and  is  also  termed  staphyloma , 
appears  under  the  form  of  bluish  elevations,  the  color  of  which  depends 
on  the  varicose  state  of  the  vessels  of  the  choroid  membrane.  It  su- 
pervenes principally  on  the  circumference  of  the  transparent  cornea 
after  arthritic  ophthalmia,  but  is  observed  more  rarely  at  the  posterior 
part  of  the  sclerotica.(9) 

The  lachrymal  sac  is  more  or  less  distended  after  inflammation  of 
the  lachrymal  passages. 

3d.  Solutions  of  continuity. 

(1)  Michaelis,  loc.  cit.,  p.  8. — Reil,  loc.  cit.,  p.  472. — Lcveillé,  in  Wenzel,  De  penit. 
struct,  cereb.,  p.  167. 

(2)  Wenzci,  in  Michaelis,  loc.  cit .,  p.  9. 

(3)  Michaelis,  loc.  cit.,  p.  3. 

(4)  Wenzel,  De  pen.  struct,  ccrcb.,  no.  xi. 

(5)  Scarpa,  Malattic  degli  occhi,  Pavia,  1801,  p.  183. 

(61  Ribes,  loc.  cit. 

(7)  Malattic  degli  occhi,  p,  230. 

(8)  J-  L.  Friedrich,  Diss.  dc  stdphylomate,  lierlin,  1821. 

(9)  Loc.  cit.,  tab.  ii.,  fig.  10.— Poraours,  loc.  cit.,  tab.  lxiv.,  fig.  3. 


OF  THE  EYE. 


181 


a.  Abnormal  union.  This  anomaly  is  rather  common,  and  always 
results  from  inflammation. 

When  the  conjunctiva  has  been  violently  inflamed  and  neglected, 
the  eyelids  join  either  to  the  anterior  face  of  the  eye  ( symblepharon ),  or 
with  each  other  ( ancyloblepharon ).  Sometimes  these  two  kinds  of 
adhesion  take  place  simultaneously.  The  parts  fused  are  sometimes 
nearer  each  other,  and  are  often  united  by  a greater  or  less  number 
of  accidental  membranes  which  vary  in  length.  Sometimes  they 
adhere  at  birth. 

After  inflammations  of  the  iris,  the  pupil  adheres  ( synizesis ),  or  the 
anterior  face  of  the  iris  imites  to  the  posterior  face  of  the  transparent 
cornea,  or  finally  the  posterior  to  the  anterior  face  of  the  crystaline 
capsule  (synechia),  by  an  effusion  of  albumen  which  coagulates,  and 
which  is  sometimes  distinct  from  the  other  parts  in  the  form  of  a 
membrane. 

The  obliteration  of  the  ducts  of  the  lachrymal  gland  is  caused  by 
external  lesions  on  the  outside  of  the  .eye.  It  depends  on  inflammation 
and  ulceration,  like  the  contractions  of  the  excretory  channels  of  the 
lachrymal  humor. 

The  shrinking  (myosis)  and  the  immobility  of  the  pupil,  observed 
after  inflammations  of  the  eye,  very  probably  result  from  an  effusion 
of  albumen  into  its  substance. 

b.  Abnormal  separation.  The  parts  of  the  eye  rarely  present  this 
anomaly  except  from  external  injuries.  We  however  must  arrange 
here  the  detachment  of  the  crystaline  lens  observed  after  violent  ce- 
phalagia  and  the  fall  of  this  lens  into  the  anterior  chamber  across  the 
pupil,  which  results  from  the  percussion  or  commotion  of  the  eye.(l) 

Ulcers  produce  especially  in  the  transparent  cornea,  sometimes  also 
in  the  iris,  solutions  of  continuity,  which,  when  situated  in  the  first  of 
these  two  membranes,  cause  the  effusion  of  the  aqueous  humor  and 
the  falling  of  the  iris.  The  iris  is  frequently  detached  in  a greater  or 
less  extent  from  the  sclerotica  by  a powerful  shock  : two  pupils  might 
then  be  said  to  exist.  We  must  refer  also  to  this  head  the  abnormal 
enlargement  of  the  openings,  for  instance,  the  pupil  (mydriasis). 

Ruptures  and  other  lesions  of  one  or  more  excretory  passages  of  the 
lachrymal  gland  form  the  lachrymal  tumor  (dacryops),  the  accumula- 
tion of  tears  between  the  conjunctiva  and  the  globe  of  the  eye,  or  a too 
great  effusion  of  this  fluid. 

Suppuration  of  the  lachrymal' sac  frequently  destroys  a portion  of 
it  and  its  communication  with  the  exterior,  and  thus  produces  fistula 
lachrymalis. 

4th.  Deviations  in  situation.  These  anomalies  extend  to  the  whole 
eye,  or  affect  some  of  its  constituent  parts  only.  The  globe  of  the 
eye  may  be  pushed  out  of  the  orbit  by  tumors  in  its  cavity  ( exoph- 
thalmia'),  and  may  fall  forward  from  the  injury  or  the  paralysis  of  its 

(1)  Fribault,  Observai  ion  sur  un  cristallin  qui  a passé  par  le  pupille  dans  la 
chambre  antérieure  de  l'œil  ; in  the  Journ.  de  méd..  vol.  lix  , p.  72. 

Vol  111  24 


182 


DESCRIPTIVE  ANATOMY 


muscles  ( ophthalmo ptosis ),  which  changes  more  or  less  the  situation 
of  the  eyelids,  and  causes  them  to  turn  over  outward. 

The  direction  of  the  eyelids  alone  is  frequently  changed,  which  may 
take  place  in  two  different  modes,  according  as  they  are  turned  out- 
ward ( ectropium ) or  inward  ( entropium ).  The  latter  effect  is  pro- 
duced particularly  by  the  destruction  of  the  internal  layer  of  the  skin 
of  the  lid  and  the  cartilage,  after  inflammation  of  the  eyelids,  by  a drop- 
sical state  of  these  parts,  sometimes  by  the  paralysis  of  the  levator 
palpebræ  muscle.  This  paralysis  however  is  never  sufficient  to  cause 
it  alone,  it  producing  only  the  fall  of  the  upper  eyelid  ( blepharoplosis ). 
The  first  state  is  caused  principally  by  wounds  in  the  skin  with  loss 
of  substance,  sometimes  also  by  the  development  of  tumors  and  ex 
crcscences  on  its  inner  face. 

When  the  fid  is  turned  inward,  the  eyelashes  naturally  ’touch  the 
globe  of  the  eye.  Hence  it  is  called  trichiasis , in  which  only  some 
lashes  participate,  which  occurs  after  inflammations  of  the  eyelids,  and 
arises  from  the  inner  part  of  the  edge  of  the  eyelids  being  destroyed  by 
ulcerations. 

The  prolapsus  of  the  iris  occurs  in  wounds  of  the  transparent  cornea, 
and  when  this  latter  membrane  presents  several  openings  through 
which  the  iiis  protrudes,  a kind  of  staphyloma  occurs  which  is  termed 
the  hunch  of  grapes.  At  first  the  protruded  portion  of  the  iris  is  ex- 
posed, soft,  thin,  and  very  vascular  ; it  gradually  becomes  solid,  the 
circulation  stops,  and  it  is  covered  by  a thin,  grayish  white  membrane, 
which  Beer  regards  as  the  regenerated  conjunctiva  ;(1)  but  it  is  more 
correct  to  consider  it  a new  production  formed  by  the  exudation  of  the 
lymph  from  the  iris. 

The  protrusion  of  the  membrane  of  the  aqueous  humor,  admitted  by 
most  writers,  is  a prolapsus  of  the  vitreous  body,  as  Scarpa  has  per- 
fectly demonstrated. (2) 

II.  ALTERATIONS  IN  COMPOSITION  AND  TEXTURE. 

§ 2024.  Almost  all  the  alterations  of  composition  and  texture  in  the 
eye,  as  in  other  parts  of  the  body,  depend  on  inflammation,  to  which 
this  organ  is  very  much  exposed.  Several  of  them  however  are  de- 
veloped, and  we  cannot  consider  them  as  resulting  exactly  from  pre- 
vious inflammation. 

Alterations  in  texture  are  very  rarely  congenital.  We  must,  how- 
ever, regard  as  such  the  anomalies  in  the  color  of  the  eye,  which  may 
be  referred  ; 1st,  to  a want  of  color  in  the  pigment  ( léucœthiopia ) ; 2d, 
to  the  different  colors  of  the  iris  in  the  two  eyes,  or  even  in  its  different 

(1)  Augcnkrankheitcn,  vol.  ii. , p.  63. 

(2)  Lou.  cit.,  p.  170, 


OF  THE  EYE. 


183 


parts  in  the  same  eye  ; 3d,  to  a want  of  transparency.  Farar  also(l) 
has  observed,  in  three  children  of  the -same  family,  that  the  cornea  at 
the  moment  of  birth  was  clouded  by  a nebulosity,  which  afterwards 
gradually  disappeared  from  the  outside  towards  the  centre. 

The  new  formations  which  must  always,  or  at  least  in  most  cases, 
be  considered  as  consequences  of  inflammation,  are  principally  the  fol- 
lowing : 

1st.  In  the  eyelids. 

a.  Grando , a rounded  tumor,  which  varies  in  hardness  and  is  de- 
veloped on  or  a little  below  the  lower  edge.  It  is  a purulent  cyst,  a 
stye  ( hordeolum ),  not  entirely  destroyed  by  suppuration,  and  which  is 
filled  with  coagulated  albumen. 

b.  Sarcoma  of  the  eyelid,  which  is  red  and  at  first  soft,  afterwards 
harder,  and  which  is  developed  on  the  inner  face  of  the  eyelids,  parti- 
cularly in  lymphatic  subjects. 

Here  we  may  mention  the  encantliis , a tumor  situated  in  the  carun 
cula  lachrymahs  and  the  third  eyelid. 

2d.  In  the  conjunctiva.  The  film  is  a greater  or  less  elevation  which 
is  developed  between  the  anterior  face  of  the  sclerotica  and  the  con- 
junctiva which  covers  it.  The  pterygium( 2)  commonly  arises  in  the 
inner  angle  of  the  eye,  where  it  extends  outward  to  the  anterior  face 
of  the  transparent  cornea,  and  beyond  the  centre  of  this  latter.  We 
rarely  find  a second  or  even  a third  in  the  external  angle  of  the  eye  or 
in  another  region.  It  is  more  or  less  vascular,  and  its  base  always 
looks  toward  the  circumference  and  its  summit  towards  the  centre  of 
the  eye,  undoubtedly  because  the  connection  of  the  conjunctiva  with 
the  subjacent  membrane  is  less  intimate  in  the  first  place  than  in  the 
second,  where  in  fact  it  blends  with  the  transparent  cornea. 

The  pannus  differs  from  the  pterygium  as  it  is  the  substance  of  the 
conjunctiva,  and  sometimes  also  that  of  the  transparent  cornea,  which 
thickens.  The  tumor  termed  pinguecula  is  generally  developed  in  the 
external  angle  of  the  eye,  or  at  least  on  the  outside  of  the  cornea.  It 
is  seldom  larger  than  a bean,  and  it  is  formed  by  the  conjunctiva  and 
the  subjacent  cellular  tissue. 

3d.  In  the  transparent  cornea( 3)  the  principal  results  of  inflamma- 
tion are  maculae  and  nebulae,  ( obscuratio , albugo,  s.  leucoma ),  which 
sometimes  arise  only  from  simple  exsudations  in  the  tissue  of  the 
cornea,  sometimes  also  are  cicatrices  of  ulcers  of  this  membrane,  and 
vary  in  their  extent  and  their  degree  of  opacity.  In  the  first  case,  the 
surface  of  the  cornea  does  not  differ  at  the  spot  where  the  point  is,  from 


(1)  Med.  communie.,  vol.  ii.,  p.  463. 

(2)  Beer  ( loc . cit.,  vol.  ii.,  p.  638)  does  not  consider  the  pterygium  as  resulting'  from 
an  inflammation.  We  may  however  mention  in  support  of  this  not  only  his  own 
opinion  that  the  tumor  usually  appears  when  caustics  are  applied  (p.  640),  but  also 
Larrey’s  observations,  who  remarked  that  it  frequently  was  a consequent  of  the 
Egyptian  ophthalmia. 

(3)  G.  Mirault,  Mémoire  sur  la  kératite  ou  inflammation  de  la  cornée  transpa- 
rente ; in  the  Arch.  gén.  de  méd .,  vol  iii.,  p.  5. 


184 


DESCRIPTIVE  ANATOMY 


other  parts  ; in  the  second  it  is  deep.  The  cicatrix  is  always  hard, 
like  the  spot  produced  by  an  old  exsudation.  Farther  we  observe  no 
other  alteration  of  texture  in  the  place  where  it  is  situated.(l) 

4th.  In  the  iris  the  pupil  is  effaced  ( atresia  pupilloe)  by  an  opaque 
false  membrane,  which  causes  at  the  same  time  the  adhesion  of  the 
posterior  face  of  the  iris  to  the  crystaline  ( synechia ) capsule.  Then 
the  production  of  pus  or  of  a puriform  fluid  on  the  surface  of  the  iris, 
whence  a puriform  congestion  is  formed  in  the  chamber  of  the  eye, 
which  is  termed  hypopon.  Scarpa  thinks  that  it  is  real  pus  which 
forms  here,  since  we  do  not  find  in  the  iris  an  abscess  the  rupture  of 
which  could  produce  this  purulent  humor. (2)  The  serous  nature  of 
the  two  faces  of  the  iris  favors  his  opinion,  but  the  authority  of  Beer(3) 
at  least  authorizes  us  to  doubt  it  as  a general  rule. 

5th.  In  the  crystaline  lens  and  ils  capsule , which  are  frequently  the 
seat  of  cataract  ( calaracla , s.  sußusio),  which  most  generally  renders 
opaque,  parts  normally  transparent. 

Cataract  varies  in  situation,  consistence,  and  color.  It  usually  arises 
from  opacity  of  the  crystaline  lens  (C.  crislallina,  C.  lenticularis),  more 
rarely  of  the  crystaline  capsule,  especially  of  its  posterior  face  ( C.  cap- 
sulaire, C.  capsularis),  still  more  rarely  in  the  humor  of  Morgagni  (C, 
laiteuse,  C.  JVlorgagniana,  s.  lactea).  These  three  kinds  coexist  in  the 
capsulo -cry  si  aline  cataract  (C.  capsulo-lenticularis) . 

Opacity  generally  commences  in  the  ccntre(4)  and  very  deeply  in 
the  crystaline  cataract,  and  on  the  contrary  in  the  margin  in  the  cap- 
sular cataract.  Sometimes  in  the  latter  case  only  some  parts  are 
opaque,  forming  the  doited  or  mottled  cataract  (C.  feneslrata).  Most 
generally,  but  not  always  in  old  men,  the  crystaline  lens  is  unusually 
hard,  and  in  a measure  ossified  or  petrified  (C.  dura).  It  is  rarely 
softer  than  in  the  normal  state  (C.  mollis),  or  even  fluid  (C.  fluida), 
The  capsule  is  more  frequently  hardened  and  thickened.  Its  anterior 
face  is  also  covered  in  some  cases  (C.  trabiculata,  pyramidala)  by  a 
layer  of  substance,  sometimes  having  the  consistence  of  osseous  tis- 
sue,(5)  which  arises  from  an  exsudation  formed  by  the  inflamed  iris, 
and  which  consequently  can  always  be  separated  to  a certain  extent 
from  the  capsule. (6)  The  color  of  the  cataract  is  most  generally 
grayish  white. 

In  the  crystaline  and  the  capsular  cataract,  the  crystaline  lens  and 
its  capsule  are  not  unfrequently  detached  from  each  other,  or  from  the 
adjacent  parts,  by  a shock  of  the  body.  But  they  are  sometimes  con- 
nected more  intimately,  and  so  extensively  that  the  crystaline  capsule 
and  the  iris  adhere. 


(1)  Wardrop,  toe.  cit.,  p.  93. 

(2)  Loc.  cit.,  p.  149. 

(3)  Loc.  cit.,  vol.  i.,  p.  436. 

(4)  Rudolphi  ( Grundriss  der  Physiologic,  vol.  ii.,  p.  184)  mentions  a family  in 
Berlin  in  which  the  central  cataract  [C.  cenf  rajas)  is  hereditary;  this  consists  in  a 
eingle  dark  point  in  the  centre  of  the  crystaline  lens,  which  remains  stationary 

(5)  Beer,  loc.  cit.,  p.  303. 

(6)  Beer,  loc.  cit.,  p 297 


OF  THE  EYE, 


185 


In  the  pyramidal  cataract  the  thick  anterior  wall  of  the  capsule 
sometimes  projects  through  the  pupil  and  advances  to  the  transparent 
cornea,  to  which  it  sometimes  adheres. 

6th.  In  the  vitreous  body,  the  loss  of  transparency  ( glaucoma ) and 
the  complete  dissolution  of  it  ( synchysis ),  which  usually  attend  gutta 
serena.(l) 

§ 2025.  The  new  formations  developed  in  the  eye  are  probably- 
caused  by  an  action  similar  to  inflammation  ; we  cannot,  however, 
always  consider  them  as  resulting  positively  from  this  cause.  They 
are  divided  as  in  every  other  part,  into  those  which  are  abnormal  only 
from  the  place  where  they  are  developed,  and  those  which  are  entirely 
new. 

1st.  Among  the  tissues  normally  existing  in  other  parts  of  the  body 
we  distinguish  : 

a.  The  cellular  tissue,  which,  assuming  the  form  of  false  membranes, 
unites  parts  which  are  primitively  separate,  and  which  we  have  al- 
ready mentioned  in  this  respect  as  produced  by  inflammation. 

b.  The  vascular  tissue,  which  arises  in  the  same  manner  in  the  dif- 
ferent new  formations,  especially  in  the  preceding. 

c.  The  serous  tissue,  which  is  developed  in  the  eyelids,  especially 
the  superior,  in  the  form  of  cysts  within  the  lachrymal  gland  in  the 
orbit, (2)  more  rarely  between  the  choroid  coat  and  the  retina.  (3)  We 
probably  can  arrange  here  the  cysts  formed  on  the  surface  of  the  iris 
when  this  membrane  projects  through  an  opening  in  the  transparent 
cornea: 

cl.  The  fibrous  tissue,  which  occurs  much  more  rarely.  In  one 
case  the  retina  was  changed  into  a white,  fibrous,  and  very  solid  mem- 
brane, exactly  similar  to  an  aponeurosis,  the  external  face  of  which 
adhered  very  intimately  to  an  osseous  layer  between  it  and  the  choroid 
membrane.  (4) 

e.  The  osseous  tissue,  which  generally  appears  in  the  form  of  more 
or  less  irregular  thin  layers  between  the  choroid  coat  and  the  retina, 
probably  from  the  change  of  the  serous  membrane  which  covers  the 
outer  part  of  the  choroid  coat.  It  is  seen  more  rarely  in  the  transpa- 
rent cornea, (5)  and  it  is  probably  developed  primitively  in  the  mem- 
brane of  Descemet. 

We  must  probably  mention  here  the  considerable  and  petrous  hard- 
ening of  the  opaque  crystaline  lens  and  the  formation  of  stony  concre- 
tions in  the  place  of  the  vitreous  body  ; for  the  latter  concretions,  even 
when  they  become  considerably  thick,  do  not  result  from  the  change 
of  the  vitreous  body,  but  from  between  the  choroid  membrane  and  the 

(1)  Heister,  in  the  Act.  nat.  cur.,  vol.  i.,  p.  71, — Demours,  loc.  cit.,  vol.  i.,  p,  390. 

(2)  Beer,  loc.  cit.,  vol.  ii.,  p.  589,  note. 

(3)  Portal,  Anat.  méd.,  vol.  iv.,  p.  418. 

(4)  Magendie,  in  Demours,  loc.  cit.,  73,  vol.  i. 

(5)  Walter,  Amt.  mus.,  vol,  i.,  p.  139. — Wardrop,  loc.  cit.,  p.  72.— Anderson,  ibid . 
p.  73. 


1S6 


DESCRTI'TIVF,  ANATOMY. 


retina,  and  only  push  this  body  outward,  since  it  is  crowded  and 
wasted  in  their  centre.(l) 

f Among1 2 3 4 5 6  the  constituent  parts  of  the  cutaneous  tissue  the  hairs 
are  probably  the  only  ones  abnormally  developed  in  the  eye,  uhless 
we  refer  to  it  those  cysts  which  form  around  hernias  of  the  iris,  and 
which  we  have  referred  to  the  serous  system.  The  conjunctiva  seems 
to  be  the  only  part  of  the  eye  where  the  hairs  take  root.  They  some- 
times appear  also  as  abnormal  eyelashes  ( distichiasis ) on  the  inner 
edge  of  the  upper  eyelid  after  neglected  ophthalmias,  and  differ  from 
the  common  lashes  in  their  situation,  thinness,  smallness,  and  whitish 
eolor.(2)  They  are  rarely  developed  in  the  conjunctiva  of  the  eye, 
where  they  appear  either  in  the  conjunctiva  itself,  which  is  most 
usual, (3)  or  on  the  transparent  cornea. (4)  In  the  cases  observed  by 
Himly  they  were  inserted  in  the  centre  of  a fatty  production,  and  in 
all  other  cases,  at  least  those  detailed  by  Wardrop,  and  Demours,  a 
pterygium  or  film  was  the  base  of  them,  that  is,  they  were  preceded 
by  a morbid  change.  Himly  and  Wardrop  have  observed  this  forma- 
tion in  the  external,  and  Demours  in  the  internal  angle  of  the  eye. 
This  latter  case  consequently  resembles  the  considerable  increase  of 
one  of  the  hairs  of  the  caruncula  lachrymalis,  seen  by  Albinus.(5)  It 
is  curious  that  in  the  few  cases  of  this  anomaly  as  yet  published,  there 
is  an  evident  connection  between  the  period  of  puberty  and  the  deve- 
lopment of  accidental  hairs.  In  the  cases  described  by  Wardrop,  the 
hairs  did  not  appear  till  the  age  of  sixteen  years  with  the  beard,  and 
in  that  described  by  Himly  the  tumor  appeared  at  the  age  of  two 
years,  but  did  not  become  troublesome  till  the  age  of  twenty,  doubtless 
because  hairs  were  not  developed  upon  its  surface. 

2d.  The  entirely  new  formations  are  : 

a.  Figlike  excrescences  which  appear  in  the  iris,  from  syphilitic 
inflammation. 

b.  Fungus  hematodes,  which  is  developed  sometimes  in  the  eye 
itself,  and  as  it  would  seem  on  the  posterior  part  of  the  choroid  mem- 
brane, whence  it  goes  forward,  destroying  before  it  all  parts  of  the 
organ,  and  often  extends  to  the  outside  of  the  eye  in  the  fat  of  the 
orbit.  Perhaps  we  ought  also  to  arrange  here  the  excrescences  which 
are  developed  within  the  optic  nerve. (6) 

c.  The  entozoaries.  To  these  may  probably  be  referred,  at  least 
sometimes,  the  loose  hydatids  which  appear  in  the  lachrymal  gland, 
and  which  are  explained  better  in  this  manner  than  by  attributing 

(1)  Scarpa,  p.  269. 

(2)  Beer,  loc.  cit.,  p.  119. 

(3)  Himly,  Ophthalm.  Bibl.,  vol.  ii.,  part  i.,  p.  199  — Ware,  On  entropion , p.  7. — 
Wardrop,  p.  31.— Demours,  tab.  Ixiv.,  fig-.  1. 

(4)  Gazelles,  in  the  Journ.  de  méd.,  vol.  xxiv. 

(5)  Annot.  acad.,  book  iii.,  cap.  viii. 

(6)  Gallereux,  in  Demours,  vol,  i.,  p.  75. 


OF  THE  NOSE. 


187 


them  to  a change  of  the  cellular  tissue.(l)  The  filaria  Medmensis 
sometimes  occurs  below  tire  conjunctiva. (2) 


CHAPTER  III. 

ORGAN  OF  SMELL. 

§ 2026.  The  senses  of  hearing  and  sight,  the  organs  of  which  have 
been  described,  differ  from  the  others  in  respect  to  their  relations  with 
other  organs,  as  they  are  more  independent.  Those  of  smell  and  taste, 
on  the  contrary,  are  only  portions  of  other  organs,  for  they  both  belong 
to  the  digestive  system,  and  the  first  also  to  the  respiratory  system. 
It  would  then  be  proper  to  consider  the  organs  of  smell,  voice,  and 
respiration,  of  taste,  and  of  digestion,  as  forming  a single  system.  It 
is  impossible  to  separate  the  history  of  the  tongue  from  that  of  the  in- 
testinal canal,  since  it  is  situated  in  a cavity,  the  commencement  of  the 
digestive  apparatus,  and  in  which  the  food  is  remarkably  changed, 
since  it  is  also  situated  behind  the  organs  which  cause  these  changes. 
But  we  shall  consider  the  organ  of  smell  separately,  since  it  is  more 
independent  than  that  of  taste,  and  after  leaving  the  fishes  it  is  entirely 
separated  from  the  respiratory  system,  which  in  the  three  upper  classes 
of  animals  communicates  with  the  exterior,  not  only  by  the  olfactory 
organ,  but  also  by  the  oral  cavity. 


ARTICLE  FIRST. 

ORGAN  OF  SMELL  IN  THE  PERFECT  STATE. 

§ 2027.  The  organ  of  smell,  or  the  nose, (3)  is  composed  : 

1st.  Of  a bony  cavity  divided  into  several  compartments,  the  upper 
and  posterior  part  of  which  is  more  extensive,  and  is  formed  by  bones, 
whence  it  is  termed  the  bony  nose  ( nasus  osseus ),  and  has  already  been 
described  in  osteology. 

2d.  Of  an  anterior,  smaller,  triangular,  elongated,  and  cartilaginous 
portion,  the  cartilaginous  portion  ( nasus  cartilagineus) . 

3d.  Of  muscles  which  move  this  cartilaginous  portion. 


(1)  Schmidt,  Krankheiten  des  Thränenorgans,  p.  75. 

(2)  Larrey,  Mémoires  et  compagnes,  vol.  i.,  p.  223. 

(3)  Santorini,  Obscrvationcs  analomicœ,  Venice,  1724,  cap.  v.,  De  naso,  p.  84. 

Ziervogel  (Aurivillius),  De  naribus  internis,  Upsal,  1760.— A.  Scarpa,  Anatomicæ 
disquisilioncs  de  audita  et  olfactu,  Milan,  1795.— T.  C.  Rosenthal,  De  organo  ol- 
t actus  quor undem  animalium,  Gripswald,  1807. — S.  T.  Scemmerring“,  Abbildungen 
des  menschlichen  Organs  des  Geruchs,  Frankfurt,  1809. 


188 


DESCRIPTIVE  ANATOMY. 


4th.  Of  a mucous  membrane  which  covers  the  osseous  and  the  car- 
tilaginous nose. 

5th.  Of  nerves  which  are  distributed  in  this  membrane. 

In  considering  the  nose  externally  we  distinguish  an  upper  part  or 
the  root,  an  anterior  edge  or  the  back,  and  a lower  part  or  the  tip. 

I.  CARTILAGINOUS  NOSE. 

§ 2028.  The  cartilaginous  nose,  the  anterior  extremity  of  the  bony 
nose,  is  composed  of  a central  and  perpendicular  portion,  the  cartilagi- 
nous septum  of  the  nose  ( septum  narium  cartilagineum),  of  two  alee. 
( pinnae , s.  alee  nasi),  finally  of  two  oblong  openings  termed  nostrils 
(jiares),  by  which  the  cavity  of  the  nose  opens  externally,  and  which 
are  supplied,  especially  on  their  inside,  with  stiff  hairs  ( vibrissa: .) 

It  is  composed  of  several  thin  cartilages  united  with  each  other  and 
with  the  bony  portion  of  the  nose,  externally  with  the  skin,  internally 
with  a mucous  membrane.  There  are  generally  eleven. 

The  largest,  the  cartilage  of  the  septum , is  perpendicular  and  square. 
It  completes  the  osseous  septum  anteriorly,  where  if  is  included  be- 
tween the  perpendicular  plate  of  the  ethmoid  bone,  the  vomer,  and  the 
median  suture  of  the  two  proper  nasal  bones.  Its  anterior  edge  de- 
scends from  before  backward,  is  loose,  and  is  attached  to  a long  pro- 
longation of  the  skin,  the  cutaneous  septum  of  the  nose. 

The  superior  lateral  cartilage  is  square  and  is  attached  to  the  lower 
edge  of  the  proper  nasal  bone,  to  the  ascending  process  of  the  superior 
maxillary  bone,  and  to  the  upper  edge  of  the  preceding.  It  is  generally 
blended  with  this  latter  so  intimately  that  they  form  but  one  body.(l) 
Below  this  superior  lateral  cartilage,  and  at  the  side  of  the  lower  part 
of  the  median  line,  is  the  inferior  lateral  cartilage,  or  the  cartilage  of 
the  ala  ( C . pinna ;),  which  is  very  low.  This  cartilage  is' narrow  and 
formed  of  two  pieces,  an  internal  and  an  external,  which  unite  forward 
at  an  acute  angle,  where  they  frequently  present  a foramen,  and  are 
sometimes  entirely  separated  from  each  other.  The  external  piece  is 
longer  and  higher  than  the  internal.  Next  come  from  before  back- 
ward and  from  without  inward  several  square  cartilages  ; these  are 
much  smaller,  diminish  in  extent  from  before  backward,  circumscribe 
the  nostril  backward  and  outward,  and  are  often  blended  with  each 
other  and  with  the  preceding.  From  two  to  five  other  still  smaller 
sesamoid  cartilages  (C.  sesamoideœ ) are  situated  forward  on  each  side, 
between  that  of  the  septum  and  the  two  lateral  cartilages. 


(1)  Santorini,  foc.  cil .,  p.  85. 


OF  THE  NOSE. 


189 


II.  MUSCLES  OF  THE  NOSE. 

§ 2029.  The  cartilaginous  nose  is  moved  by  a great  many  mus- 
cles, ( 1)  two  of  which  belong  to  it  exclusively  and  two  are  common 
with  the  adjacent  parts. 

A.  LEVATOR  ALS  NASI  LABIIQUE  SUPERIORIS. 

§ 2030.  The  levator  alee,  nasi  labiique  svperioris  or  the  pyramidal 
muscle,  grand  sus-maxillo-labial,  Ch.,  arises  from  the  nasal  process  of 
the  upper  maxillary  bone,  usually  blends  in  this  place  with  the  frontalis 
muscle,  descends  in  the  side  of  the  nose,  and  divides  into  two  fasciculi, 
an  anterior  which  is  smaller,  and  is  expanded  in  the  lower  lateral  car- 
tilage ; the  other  is  much  larger,  and  blends  with  the  orbicularis  oris 
and  the  superior  muscles  of  the  upper  lip.  It  raises  the  ala  of  the 
nose  and  the  upper  lip,  and  opens  the  nostril. 

B.  COMPRESSOR  NARIUM. 

§ 2031.  The  compressor  narium  muscle,  sus-maxillo-nasal , Ch.,  is 
triangular,  thick,  and  narrow  at  the  base,  and  broad  above.  It  ascends 
from  the  posterior  part  of  the  ala  of  the  nose,  where  it  is  blended  with 
the  preceding,  which  partly  covers  it,  and  goes  from  behind  forward 
toward  the  back  of  the  nose,  on  which  it  unites  with  that  of  the  op- 
posite side  without  any  intermediate  tendon.  It  often  gives  off  at  the 
upper  part,  a prolongation  which  blends  with  the  frontalis  muscle. 
This  is  the  procerus  muscle  of  Santorini,  the  lower  part  of  his  Irans- 
versus  nasi  muscle. 

It  contracts  the  nostrils  when  it  acts  from  below  upwarc^  or  from 
above  downward,  and  never  dilates  them. 

C.  DEPRESSOR  ALÆ  NASI. 

§ 2032.  The  depressor  alee  nasi  muscle,  the  proper  muscle  of  the 
ala  ( JMT.  pinnarum,  s.  narium  lateralis , Santorini,  s.  dilator  narium  pro- 
prius , s.  inferior ),  arises  from  the  upper  maxillary  bone  above  the 
c.anine  tooth  and  the  external  incisor.  It  is  formed  of  oblique  fibres, 
and  extends  almost  the  whole  length  of  the  outside  of  the  cartilage  of 
the  ala  of  the  nose.  Its  principal  effect  is  to  dilate  the  nostril  when 
the  nose  is  at  rest.  Being  inserted  in  the  upper  maxillary  bone,  it 
can  depress  the  nose.  Finally,  as  its  external  face  is  attached  to  the 
integuments  of  the  upper  lip,  it  can  also  depress  this  latter; 

(1)  Santorini,  Obs.  anat.,  cap.  i.,  de  musculis  faciei,  p.  11. — Id.,  Tabulas  XVII., 
tab.  i. — A.  F.  Walter,  Tenor,  muse.  hum.  corp.  anat.  repet.,  Leipsic,  17-31. — Isen- 
flannn  has  described  and  figured  them  in  his  Praktische  Anmerkungen  über  die 
Muskeln,  Erlangen,  1778,  p.  345. 

Vol.  III. 


25 


190 


DESCRIPTIVE  ANATOMY. 


We  sometimes  find  before  it  a proper,  but  much  smaller  muscle,  to 
dilate  the  nostril  ; it  is  called  the  myrtiform  muscle  of  Santorini , and 
sometimes  surrounds  the  nose  like  a sphincter. 

D.  DEPRESSOR  NARIUM. 

§ 2033.  The  depressor  narium  muscle  forms  on  each  side  a small  fasci- 
culus situated  along  the  median  line  : it  arises  from  the  inner  upper 
part  of  the  orbicularis  oris  muscle,  and  is  attached  backward  and  in- 
ward to  the  inner  branch  of  the  cartilage  of  the  ala  of  the  nose.  It 
draws  the  cartilaginous  nose  downward  and  backward,  and  also  con- 
tracts the  nostrils. 

III.  MUCOUS  MEMBRANE, 

§ 2034.  The  mucous,  olfactory,  pituitary,  or  Schneiderian  mem- 
brane of  the  nose,  has  not  the  same  nature  in  all  parts.  The  proper 
nasal  portion  is  more  than  a line  thick  in  some  places  ; it  is  thick,  very 
red,  and  intimately  fitted  to  the  bones  which  it  covers  in  every  part  ; it 
contains  numerous  depressions  and  mucous  follicles,  and  also  at  the 
lower  and  inner  part  of  the  nose,  some  small  yellowish  and  distinct 
glands,  which  are  imbedded  in  its  peculiar  tissue.  At  the  anterior  and 
inferior  part  of  the  nose  it  is  thinner,  harder,  drier,  and  also  provided 
with  mucous  follicles.  If  we  except  this  latter  portion,  the  pituitary 
membrane  is  covered  in  every  part  with  very  short  villosities.  At  the 
lower  edge  of  the  septum  there  is  not  unfrequently  a narrow  canal, 
the  direction  of  which  is  from  behind  forward,  terminating  posteriorly 
in  a cul-de-sac,  and  which  opens  at  some  distance  behind  the  anterior 
edge,  evidently  above  the  organ  of  Jacobson.(l) 

The  mucous  membrane  of  the  accessory  cavities  or  of  the  sinuses, 
is  externally  thin,  smooth,  and  yellowish  white.  It  adheres  but  slightly 
to  the  surface  of  the  bony  cavities  it  covers,  undoubtedly  because  nu- 
merous vessels  and  nerves  do  not  enter  it,  through  the  substance  of 
the  bones. 

IV.  nerves. 

§ 2035.  The  nose  receives  its  nerves  from  two  sources,  the  olfactory 
and  the  second  branch  of  the  trifacial  nerve. (2) 

The  olfactory  nerve  is  undoubtedly  the  proper  nerve  of  the  organ  of 
smell, (3)  since  when  absent  or  compressed,  the  sense  of  smell  is  lost. 

(1)  Ruysch,  Thesaur.  anat.  III.  tab.  v.,  fig.  5. — Jacobson,  Ann.  du  mus.,  vol. 
xviii.  p.  412. 

(2)  J.  Hunter,  A description  of  the  nerves  which  supply  the  organ  of  smelling  ; in 
Obs.  on  different  parts  of  the  animal  economy,  p.  239,  tab.  ix-xviii. — A.  Scarpa,  loc. 
eit.,  cap.  iii-vi. 

(3)  Magendie  has  doubted  the  proposition  generally  admitted  in  a memoir,  en- 
titled “ Le  nerf  olfactif  est-il  l’organe  de  l’odorat  ? In  the  Journ.  de  phys.  expér., 
vol.  iv.  p.  169.”  Mery  already  doubted  that  the  olfactory  nerve  was  the  organ  of 
smell,  and  asserted  that  it  was  supplied  by  the  fifth  pair.  (Brunet,  Progrès  de  la 


OF  THE  NOSE. 


191 


From  the  lower  face  of  the  prominence  which  terminates  it,  two  series 
of  filaments  arise,  an  external  and  an  internal,  which  correspond  to  the 
two  series  of  foramina  in  the  cribriform  plate  of  the  ethmoid  bone, 
although  two  or  three  of  them  frequently  emerge  through  the  same 
foramen.  They  vary  much  in  number  and  size.  There  are  from  four 
to  twelve.  The  anterior  go  downward  and  forward,  the  middle  di- 
rectly downward,  the  posterior  downward  and  backward.  Shortly 
after  leaving  the  olfactory  nerve  they  enter  the  sheaths  of  the  dura- 
mater,  within  which  the  posterior,  particularly,  pass  a long  distance 
before  entering  the  foramina  of  the  cribriform  plate.  They  are  covered 
first  by  the  dura-mater,  and  flattened  by  the  arachnoid  membrane, 
which  is  less  compact,  and  does  not  attend  them  as  far.  Entirely  on 
the  outside,  each  is  surrounded  by  a tunnel-like  prolongation  of  the 
dura-mater,  which  extends  very  far,  and  makes  them  apparently  larger 
than  they  are  on  leaving  the  ganglion.  They  anastomose  below  the 
cribriform  plate,  descend  between  the  bones  and  the  pituitary  mem- 
brane, soon  ramify  very  much,  and  thus  gradually  approach  the  loose 
surface  of  the  membrane. 

Part  of  the  internal  seiies  belongs  to  the  septum,  the  component 
nerves  of  which  pass  entirely  through  it  : the  middle  are  the  longest  and 
the  posterior  the  shortest. 

They  descend  side  by  side,  forming  a single  layer. 

The  external  series  is  distributed  in  the  sides  of  the  nose,  particularly 
in  the  two  superior  turbinated  bones,  forms  considerable  anastomoses, 
but  the  filaments  formed  by  these  nerves  are  much  less  compact  than 
those  of  the  external  : they  do  not  enter  into  the  ethmoid  cellules,  and 
do  not  go  to  the  mucous  membrane  of  the  inferior  turbinated  bones,  or 
at  least  send  forward  but  few  and  very  minute  minuscules. 

The  olfactory  nerve  sends  no  filaments  to  the  pituitary  membrane  of 
the  sinuses. 

médecine,  1697.)  Having  opened  the  skulls  of  three  or  four  men,  in  whom  the  organ 
of  smell  during  life  was  unaltered,  he  found  the  pair  of  nerves  callous  near  the  cere- 
brum. Loder,  however,  (Observatio  tumoris  scirrhosi  in  basi  cranii  reperti,  Jena, 
1779,)  has  seen  the  olfactory  nerve  destroyed  in  a man  destitute  of  the  power  of  per- 
ception, and  Oppcrt  also  has  observed  the  same  thing  in  a female,  in  whom  the  sense 
of  smelling  was  deficient  (Diss.  de  vitiis  nervorum  organicis,  Berlin,  1815,  p.  16). 
Cerutti  ( Beschreibung  der  pathologischen  Präparate  des  anatomischen  7 'heaters  zu 
Leipzig,  1819,  p.  208)  mentions  the  cerebrum  of  a • îan  who  never  possessed  the 
faculty  of  smelling,  in  whom  the  olfactory  nerve  and  its  groove  on  the  lower  face  of 
the  inferior  lobe  were  deficient.  Rosenmuller  even  has  described  this  case  (De  de- 
fcclu  nervi  olfac.,  Leipsic,  1817).  But  Rudolphi  regrets,  and  with  justice,  that  the 
turbinated  bones  of  the  septum  were  not  examined,  since  in  many  cases,  when  it  has 
been  said  to  be  deficient,  it  has  been  found,  but  very  soft  and  diffluent.  Farther, 
the  facts  related  by  Magendie,  seem  to  give  some  weight  to  the  old  opinion  of  Mery  ; 
at  least  they  should  draw  the  attention  of  physiologists  to  the  sinuses  of  the  nasal 
fossæ,  to  which  Malacarne,  Weinhold,  Blumenbach,  and  Treviranus,  have  attri- 
buted very  different  uses,  which  are  sometimes  very  trivial,  as  those  mentioned  by 
Weinhold.  It  would  be  important  to  prove,  whether,  as  Deschamps  and  Richerand 
assert  from  experiments  made  on  subjects  affected  with  diseases  of  these  cavities, 
they  are  unconnected  with  the  olfactory  function;  but  of  this  we  may  doubt  until  we 
have  more  information,  especially  since  the  fine  researches  of  Treviranus  on  the 
fifth  pair  of  nerves.  F,  T. 


192 


DESCRIPTIVE  ANATOMY. 


Among  the  nerves  of  the  fifth  pair  or  the  accessory  nerves  of  the 
nose,  the  superior  nasal  nerves  go  backward,  the  middle  and  the  in- 
ferior nasal  nerves,  and  the  nerve  of  the  septum  which  arise  from  the 
pterygo-palatine  nerve,  and  the  ethmoid  nerve  which  comes  from  the 
nasal  branch,  go  farthest  forward,  for  they  extend  even  before  the  ol- 
factory nerve,  and  are  distributed  in  the  mucous  membrane  of  the  nose. 
These  nerves  also  surround  the  surface  in  which  the  olfactory  nerve 
is  distributed,  and  anastomose  with  its  posterior  and  external  filaments. 
Those  from  the  second  branch  of  the  fifth  pair  communicate  also  with 
the  ethmoid  nerve.  Hence,  the  accessory  nerves  form  a complete 
circle  around  the  expansion  of  the  olfactory  nerve,  like  that  formed  by 
the  ciliary  nerves  around  the  retina.  Although  they  proceed  much 
farther,  they  however  occupy  much  less  space  than  the  twigs  of  the 
olfactory  nerve. 

§ 2036.  The  impressions  of  the  odors  are  received  by  the  olfactory 
nerve,  and  directly  by  the  pituitary  membrane.  The  portion  of  this 
latter  in  which  the  olfactory  nerve  is  distributed,  seems  to  be  the  prin- 
cipal seat  of  the  faculty  of  perceiving  them,  although  the  membrane 
which  lines  the  sinuses,  partially  contributes. 


ARTICLE  SECOND. 

DIFFERENCES  IN  THE  NOSE  DEPENDENT  ON  DEVELOPMENT. 

§ 2037.  We  have  already  mentioned  in  osteology,  the  principal 
periodical  differences  in  the  bony  nose. 

The  whole  organ  long  continues  very  imperfect.  There  is  no  trace 
of  the  external  nose  until  the  seventh  or  eighth  week  of  pregnancy. 
At  this  time  the  nostrils  appear,  separated  by  a proportionally  very 
broad  septum,  as  two  very  small  openings  ; little  later  the  nose  begins 
to  project  over  the  mouth  ; but  during  pregnancy  it  is  blunt,  and  pro- 
portionally very  small  ; a large  nose  in  an  infant  is  very  unpleasant, 
because  it  is  a character  foreign  to  the  early  periods  of  life. 

The  cartilaginous  structure  of  the  external  nose  does  not  begin  to 
appear  till  towards  the  end  of  the  third  month. 

Until  the  end  of  the  second,  the  nasal  cavity  communicates  with  that 
of  the  mouth.  It  is  at  first  very  narrow  from  above  downward,  and 
from  right  to  left,  on  account  of  the  greater  breadth  of  the  septum. 

The  nasal  canals  are  formed  at  the  end  of  the  second  month,  by  the 
still  membranous  prominences  of  the  turbinated  bones. 


OF  THE  NOSE. 


193 


ARTICLE  THIRD. 

ORGAN  OP  SMELL  IN  THE  ABNORMAL  STATE. 

A,  NOSE. 

§ 2038.  The  primitive  deviations  of  formation  in  the  nose(l)  are  : 

1st.  Its  entire  deficiency,  which  is  very  rare,  is  generally  attended 
with  the  fusion  of  the  two  eyes  in  one. 

2d,  The  union  of  the  two  halves  of  the  nose  in  a tube  situated 
below  the  single  eye. 

3d.  Greater  or  less  openings  in  the  septum. 

4th.  Narrowness  or  closing  of  the  nostrils. 

5th.  The  abnormal  communication  of  the  cavity -of  the  nose  with 
that  of  the  mouth,  by  the  deficiency  of  a greater  or  less  portion  of  the 
palate.  (2) 

6th.  The  more  or  less  evident  want  of  symmetry  arising  from  an 
obliquity  in  the  septum,  which  is  sometimes  so  great  that  this  latter 
even  touches  the  wall  towards  which  it  inclines. 

Most  of  these  primitive  deviations  of  formation  are  developed  also 
consecutively  during  life,  after  the  bony  and  musculo-membranous 
parts  of  the  nose  and  palate  are  destroyed  by  syphilis. 

The  most  frequent  abnormal  formations  are  the  polypi  of  the  pitui- 
tary membrane.  Hydatids  are  infinitely  more  rare.  They  sometimes 
become  so  large  that  they  considerably  contract  the  nasal  cavity.(3) 

B.  SINUSES  OF  THE  NASAL  F0SSÆ. 

§ 2039.  The  accessory  cavities  or  the  sinuses  of  the  nasal  fossœ , pre- 
sent numerous  and  frequent  anomalies.(4) 

Their  deviations  of  formation  consist  in  their  absence  and  narrow- 
ness, which  are  usually  congenital.  Sometimes  these  sinuses  do  not 
communicate  with  the  nasal  fossæ  : but  this  anomaly  almost  always 
occurs,  consecutively,  after  inflammation. (5) 

Once,  however,  we  found  in  the  cadaver  of  an  old  woman  the  two 
maxillary  sinuses  completely  closed,  without  any  pathological  change 

(1)  Deschamps,  Traité  des  maladies  des  fosses  nasales  et  de  leurs  sinus,  Paris, 
1804,  p.  8. 

(2)  Portai,  Anat.  méd .,  vol.  iv.  p.  499. 

(3)  Idem,  loc.  cit. 

(4)  L.  H.  Runge,  De  morbis  prœcipuis  sinuum  assis  frontis  et  maxilice  superior  is, 
Rinteln,  1750. — Bordenave,  Sur  les  maladies  du  sinus  maxillaire  ; in  the  Mem.  de 
Vac.  de  chir.,  vol.  iv.  p.  329. — C.  A.  Weinhokl,  TJ  cher  die  krankhaften  Metamorphosen 
der  Highmorshöhle,  Leipsic,  1810. — F.  D.  Wagner,  Diss.  de  po'lypis  nariumet  antri 
maxillaris,  Berlin,  1821. 

(5)  A.  F.  Rohowsky,  Diss.  de  choanarum  obliteratione,  Berlin,  1815,— Otto,  Patho- 
logische Anatomie , p.  203,  ann.  15. 


194 


DESCRIPTIVE  ANATOMV. 


in  the  texture  of  the  pituitary  membrane,  and  their  surface  also  was 
moist  as  usual. 

A greater  or  less  quantity  of  liquid,  however,  often  collects  within 
them,  from  the  effect  of  certain  causes  ; this  more  or  less  forcibly  dis- 
tends them,  their  parietes'  become  thinner,  and  are  finally  destroyed 
when  the  compression  continues  a long  time,  although  this  state  does 
not  deserve  the  name  of  dropsy  of  the  maxillary  sinus,  because  the 
effused  liquid  is  not  of  the  same  nature  as  that  exhaled  by  serous  mem- 
branes. ( 1) 

Entirely  new  formations,  as  fibro-cartilages  and  polypi,  either  alone 
or  united,  are  not  unfrequently  developed  in  the  accessory  cavities  of 
the  nose.  These  formations  are  particularly  common  in  the  maxillary 
sinus,  which  is  the  most  subject  to  morbid  alterations,  doubtless  on  ac- 
count of  the  nearness  of  the  teeth,  and  because  the  situation  of  its 
opening  renders  the  escape  of  its  secreted  fluids  more  difficult.  We 
may,  however,  blend  them  with  the  analogous  tumors  which  are  deve- 
loped out  of  the  antrum  Highmorianum,  in  the  zygomatic  fossa. (2) 

SECTION  II. 

OF  THE  VISCERA  OR  FORMATIVE  ORGANS. 

§ 2040.  The  viscera, { 3)  which  may  also  be  called  the  formative  or- 
gans, because  their  essential  function  is  to  form  new  substances,  pre- 
sent several  general  characters,  the  principal  of  which  are  as  fol- 
low : 

1st.  They  are  situated  principally  in  the  trunk,  and  occupy  only  a 
small  part,  of  the  lower  region  of  the  face,  and  are  generally  placed  in 
cavities  formed  by  bones,  muscles,  and  serous  membranes,  which  vary 
much  in  capacity.  An  aqueous  vapor  is  effused  between  them  and  the 
parietes  of  these  cavities. 

2d.  They  are  entirely,  or  at  least  in  great  part,  and  in  their  most 
important  portions,  enveloped  by  serous  membranes.  Each  system  is 
separated  in  this  manner  from  the  others,  and  each  occupies  a distinct 
section  of  the  trunk. 

3d.  They  receive  most  of  their  nerves  from  the  ganglionnary  sys- 
tem, and  their  nerves  are  always  proportionally  larger  than  those  that 
go  to  the  organs  of  sense,  excepting  always  certain  parts,  as  the  tongue 
and  the  external  organs  of  generation,  which  being  abundantly  sup- 
plied with  nerves,  possess  a very  acute  and  special  sensibility,  and  are 

(1)  Runge,  loc.  cit. — Fauchard,  Chir.  dentiste , vol.  i. — Sauve,  Cas  d’hydropisie 
du  sinus  maxillaire  ; in  the  Bull,  de  la  fac.  de  mcd.,  1818,  p.  9. 

(2)  Lesage,  Sur  une  tumeur  enkystée  de  la  fosse  zygomatique  prise  pour  un  polype 
du  sinus  maxillaire  ; in  the  Bull,  de  la fac.  de  mcd.,  1816,  vol.  v.  p.  268. 

(3)  R.  C.  de  Garengeot,  Splanehnologie,  ou  l’anatomie  des  viscères,  Paris,  1742. — 
Gavard,  Traité  de  splanehnologie,  Paris,  1809.— Boyer,  Traité  de  splanehnologie, 
Paris,  1815. 


OF  THE  VISCERA. 


195 


in  fact,  real  organs  of  sense.  Most  of  the  viscera  receive  their  nerves 
from  the  ganglionnary  system,  and  next  from  the  pneumogastric  nerve  ; 
but  the  hypoglossal,  the  glosso-pharyngeal,  and  the  trifacial  nerves, 
are  also  distributed  in  their  upper  portion,  and  the  inferior  spinal  nerves 
in  their  lower  portion. 

The  nerves  usually  pass  some  distance  before  arriving  at  the  organs, 
and  generally  each  of  the  latter  receives  nerves  from  one  pair  only. 
One  pair  of  nerves  is  distributed  in  part  to  several  organs. 

4th.  The  course  of  the  nerves  in  most  of  their  extent  is  constant. 
As  this  condition  does  not  exist  in  regard  to  those  organs  which  re- 
ceive their  nerves  from  the  ganglionnary  system,  we  must  conclude 
that  it  does  not  depend  on  the  nature  of  this  nerve.  It  is  false  that 
the  spiritual  principle  is  not  connected  with  them,  and  the  changes 
that  take  place  in  them  are  not  perceived  ; this  perception  is  very  mani- 
fest in  disease,  and  the  sensations  that  result  from  them  are  not  more 
vague  or  obscure  than  those  ascribed  to  all  the  organs  except  that  of 
sight.  _ v 

5th.  All  the  viscera  are  not  united,  at  least  in  the  perfect  state,  by 
mucous  membranes.  The  respiratory  and  digestive  systems  commu- 
nicate together  in  the  neck,  the  urinary  and  genital  systems  in  the 
lower  part  of  the  trunk  ; but  the  two  latter  are  separated  from  the  di- 
gestive system,  or  at  least  are  connected  with  it  only  by  the  skin. 

6th.  These  organs  are  much  less  symmetrical  as  to  form  and  situa- 
tion, than  those  of  the  senses. 

7th.  Their  most  important  part  is  more  or  less  evidently  glandular, 
All  are  formed  by  several  glands,  the  combined  action  of  which  is  to 
correct  the  fluids  secreted  by  them.  The  necessity  of  the  combined 
action  of  several  glands  is  very  evident  in  the  most  complex  system, 
that  of  digestion.  Next  come  in  this  respect  the  genital  organs,  espe- 
cially those  of  the  male.  The  concurrence  of  several  glands  to  form  a 
new  substance,  seems  least  necessary  in  the  urinary  and  respiratory 
systems. 

A second  part  is  composed  of  a canal  formed  of  several  different 
superimposed  membranes,  united  by  cellular  tissue,  and  with  which 
the  gland  or  glands  in  general  communicate,  and  which  is  sometimes 
open  at  its  two  extremities  like  the  alimentary  canal,  or  at  one  only, 
like  all  the  others.  The  nature  of  the  parietes  of  this  canal  varies  ex- 
tremely ; they  are,  however,  always  formed  of  at  least  two  superim- 
posed layers,  the  external  of  which  is  condensed  cellular  tissue,  and  the 
internal  a mucous  membrane.  The  mucous  membrane  is  covered 
sometimes  in  every  part,  as  in  the  alimentary  canal,  sometimes  here 
and  there  by  a muscular  tunic. 

8th.  These  organs,  if  we  except  the  genital  organs,  are,  next  to  the 
centres  of  the  nervous  and  circulatory  systems,  the  most  necessary  for 
the  support  of  life,  although  some  of  their  parts  may  be  primitively  de- 
ficient, or  be  destroyed  in  some  manner  without  occasioning  severe 
accidents,  and  although  very  considerable  alterations  do  not  occasion 
immediate  death, 


196 


DESCIUrXIVE  ANATOMY. 


CHAPTER  I. 

OF  THE  DIGESTIVE  ORGANS. 

§ 2041.  The  digestive  organs  comprise  an  uninterrupted  canal 
open  at  its  two  extremities,  and  several  appendages, which,  communi- 
cate directly  or  indirectly  with  different  parts  of  this  canal,  within 
which  they  empty  a fluid  prepared  by  them. 

This  passage  is  termed  the  alimentary  canal  or  tube  ( canalis , s. 
ductus  cibarius).  Its  upper  extremity  is  the  mouth  (os),  and  the  lower 
the  amts  ; both  are  situated  opposite  each  other,  and  nearly  on  the 
same  line.  The  canal  is  imperfectly  divided  by  valvular  prominences 
into  several  separate  portions,  which  are  named  according  to  their 
form  or  functions.  It  is  very  convenient  to  admit  three  parts,  which 
differ  in  functions,  structure,  and  situation,  but  which  are  all  repeti- 
tions of  the  same  type  ; these  are  the  upper,  the  middle,  and  the  lower 
portion.  The  first  occupies  the  head,  the  neck,  and  the  chest  ; the 
other  two,  which  form  most  of  the  digestive  system,  fill  almost  entirely 
the  cavity  of  the  abdomen.  The  upper  portion  is  composed  of  the  oral 
cavity  ( cavmn  oris),  the  pharynx,  which  is  smaller  than  the  mouth, 
and  the  esophagus  ( gula , oesophagus),  which  is  still  narrower,  and  with 
which  the  pharynx  is  continuous.  ■ Directly  after  passing  through  the 
diaphragm  the  alimentary  canal  enlarges  to  form  a second  pouch, 
called  the  stomach  ( ventricidus , stomachus),  which  is  the  commence- 
ment of  the  middle  portion.  Next  comes  a second  narrower  portion, 
the  small  intestine  ( intestinum  tenue),  which  is  divided,  from  slight  and 
inessential  differences,  into  the  duodenum,  the  jejunum,  and  the  ileon. 
The  latter  is  continuous  with  the  terminating  portion  of  the  intestinal 
canal,  the  large  intestine  or  the  colon  ( intestinum  colon,  s.  crassum), 
which  is  divided  according  to  the  situation  and  direction  of  its  different 
parts  into  an  ascending,  a transverse,  and  a descending  colon.  The 
latter  is  continuous  also  with  the  rectum,  which  opens  at  the  anus. 
The  small  and  the  large  intestines  are  termed  the  intestinal  canal 
( ductus , s.  canalis  intestinalis) . 

The  appendages  of  the  intestinal  canal  are  glandular  organs  re- 
sembling conglomerate  glands  ; they  are,  the  salivary  glands  and  the 
liver. 

The  salivary  glands  ( G . salivares)  are  situated  around  the  cavtiy  of 
the  month,  into  which  their  secretion  goes,  and  in  the  abdominal  ca- 
vity near  the  upper  extremity  of  the  small  intestine.  They  are  con- 
sequently divided  into  the  oral  and  the  abdominal  salivary  glands  ( G. 
salivares  orales  et  abdominales). 

The  liver  ( jecur , heparj  also  occupies  the  cavity  of  the  abdomen. 
The  fluid  it  secretes  is  termed  bile,  and  is  poured  into  the  duodenum 
near  the  last  salivary  gland. 


OF  THE  DIGESTIVE  SYSTEM. 


197 


We  also  find  in  the  abdomen  a glandular  organ,  which  has  no  ex- 
cretory canal,  called  the  spleen  ( splen , lien). 

All  the  portions  of  the  digestive  system  in  the  abdomen,  except  the 
lower  part  of  the  rectum,  are  surrounded  by  a common  serous  mem- 
brane, the  peritoneum. 

§ 2042.  The  alimentary  canal(l)  presents  several  general  charac- 
ters which  are  simply  modified  in  its  component  parts. 

The  tube  it  represents  is  formed  of  several  layers  which  belong  to 
different  systems,  so  that  each  concurs  specially  to  the  general  func- 
tion. 

The  most  internal  and  the  most  essential  of  these  layers  is  the  mu- 
cous or  villous  membrane  ( tunica  mucosa , a.  intima , s.  cribrosa , s. 
villosa).  It  is  soft  and  more  or  less  vascular,  incloses  numerous  small 
culs-de-sac  or  small  muciparous  glands,  and  its  surface  is  moistened 
by  the  mucus  which  it  constantly  secretes,  and  a thinner  fluid  which 
is  exhaled  from  it.  It  is  in  direct  contact  with  the  ingesta.  The  liquid 
which  it  secretes  has  .a  chemical  and  also  a dynamical  relation  with 
the  ingesta,  since  its  action  changes  their  composition,  and  they  are 
divided  into  two  parts,  one  of  which,  the  chyle  (cliylus),  serves  for 
nutrition,  while  the  other,  the  fecal  matter  {faces),  being  useless,  is  ex- 
pelled from  the  body.  The  chyle  in  its  turn  is  so  modified  that  it  enters 
into  the  absorbing  vessels  which  exist  in  this  tissue. 

The  differences  in  this  membrane  relate  principally  . 

1st.  To  its  thickness. 

2d.  To  its  vascularity. 

3d.  To  its  color,  which  depends  on  the  number  of  its  vessels. 

4th.  To  its  solidity. 

5th.  To  its  extent,  compared  with  the  other  membranes. 

6th.  To  the  presence  or  absence  of  prolongations  and  folds  which 
project  within  it  and  vary  in  size,  the  former  of  which  are  called  valves, 
the  others  mllosities. 

7th.  To  the  nature  of  its  surface,  which  is  smooth  or  corrugated, 
and  which  depends  on  the  preceding  circumstance. 

8th.  To  the  number  of  the  muciparous  glands. 

9th.  To  their  size. 

10th.  To  their  situation  and  arrangement. 

We  may  mention  as  a general  law  that  the  development  of  the 
inequalities  on  the  inner  face  is  inversely  as  that  of  the  muciparous 
follicles,  or  still  more  generally  that  the  prominences  are  inversely  as 
the  depressions  ; that  the  first  are  more  distinct,  the  more  nutrition  there 
is  in  the  contents  of  the  intestinal  canal,  and  that  the  cavities  are  more 
marked,  the  greater  the  quantity  of  fecal  matter  in  the  canal. 

Considered  from  the  commencement  of  the  stomach  to  the  extremity 
of  the  intestinal  canal,  the  general  character  of  this  membrane  is  that 
it  is  perforated  by  very  , numerous  small  openings,  which  are  the  ori- 


(1)  F.  Glhson,  De  oentriculo  et  intestinis,  London,  167(5. 

Vol.  Ill  2.6 


198 


DESCRIPTIVE  ANATOMY 


lices  of  single  minute  glands,  and  which  are  arranged  very  corn- 
pactly.(l) 

On  its  surface  is  a second  membrane  termed  the  nervous , or  rather 
the  cellular  coat  ( tunica  nerve«,  ccllulosa). 

This  membrane  is  only  condensed  cellular  tissue,  in  which  the 
largest  trunks  of  the  vessels  and  nerves  are  distributed  before  arriving 
at  the  mucous  membrane. 

It  contributes  much  to  determine  the  form  of  the  intestinal  canal 
and  of  its  folds. 

The  most  external  membrane  is  the  muscular  tunic  ( tunica  muscu- 
lo sa.) 

This  membrane  is  composed  in  every  part  by  several,  at  least  two, 
superimposed  layers,  situated  one  above  the  other,  and  separated  only 
by  a very  thin  layer  of  mucous  tissue. 

The  external  layer  is  generally  composed  of  longitudinal  fibres, 
which  are  parallel  to  the  axis  of  the  intestinal  canal  and  of  the  body 
It  is  thinner  than  the  internal,  and  it  is  extended  on  the  intestine  less 
uniformly. 

The  internal,  on  the  contrary,  is  composed  of  circular  fibres,  is 
stronger  than  the  external,  and  completely  surrounds  the  intestinal 
tube. 

The  differences  presented  by  this  muscular  tunic  in  the  different 
regions  of  the  alimentary  canal  relate  : 

1st.  To  the  relation  between  it  and  the  mind,  according  as  its  mo- 
tions are  voluntary  or  involuntary  ; in  most  of  its  extent  these  are 
involuntary  ; they,  however,  are  voluntary  at  its  upper  and  lower  part 

2d.  To  its  thickness  and  strength. 

3d.  To  its  more  or  less  complex  texture. 

4th,  To  its  color. 

5th.  To  its  attachments,  according  as  it  is  inserted  in  the  bones  or 
connected  with  the  adjacent  parts  by  mucous  tissue. 

Besides  these  three  layers  there  are  also  two  others  which  are  not 
so  generally  distributed  : one  resembles  the  epidermis,  and  covers  the 
inner  membrane  ; the  other  is  given  off  by  the  peritoneum,  and  enve 
lops  the  external  tunic. 

The  most  general  character  of  the  glandular  appendages  of  the 
alimentary  canal  is,  that  these  parts,  except  the  spleen,  are  prolonga- 
tions of  the  mucous  membrane  and  of  the  cellular  tunic,  each  of  which 
ramifies  like  a tree.  They  differ  then  from  the  muciparous  glands  on 
the  external  face  of  the  villous  tunic,  because  they  are  rather  more 
distinct  and  are  more  concentrated  in  some  parts  of  the  alimentary 
canal. 

(1)  Galoati,  Dc  tunica  Lntestinorum  cribrosu;  in  (lie  Comm.  Bonon,t  vol.  i. — 
Duverney,  Œuvres  anatomiques,  vol.  i,,  p.  480.— A.  Muck  cl,  > Sur  la  structure  dc  la 
membrane  muqueuse  des  intestins  dans  l'homme  et  dans  quelques  animaux  ; in  the 
Journ.  compt.  des  sc,  mcd.,  vol.  vii.,  p.  209. 


OF  THE  DIGESTIVE  SYSTEM 


199 


ARTICLE  FIRST. 

UPPER  PORTION  OF  THE  ALIMENTARY  CANAL, 

§ 2043,  The  upper  portion  of  the  alimentary  canal  may  be  subdi- 
vided into  two  regions,  a cephalic  and  a cervical  region 

I CEPHALIC  PORTION  OF  THE  ALIMENTARY  CANAL 

§ 2044.  The  cephalic  portion  of  the  alimentary  canal  comprehends 
the  cavity  of  the  mouth  and  the  parts  within  it 

A.  ORAL  CAVITY  GENERALLY, 

I.  PERFECT  STATE. 

§ 2045.  The  oral  cavity  ( cavum  oris ) occupies  the  lower  part  of 
the  face.  It  extends  backward  to  the  fauces  and  forward  to  the  lips, 
by  which  it  is  continuous  with  the  face.  It  is  separated  from  the 
nasal  fossæ  above  by  the  bony  palate  ( palatum  osseum,  s.  dumm),  and 
backward  by  the  soft  palate  ( palatum  molle,  s.  velum  palati).  At  its 
base  is  the  tongue,  and  on  its  sides  the  lower  jaw,  the  zygomatic  arch, 
and  the.  muscles,  some  of  which  are  attached  to  these  hones,  others  to 
other  pieces  of  bone,  and  several  of  which  also  go  to  the  mouth. 

As  the  oral  cavity  is  circumscribed  by  muscles  and  by  bones  which 
are  movably  articulated  with  each  other,  its  form  varies,  although  in 
general  it  is  rounded  and  oblong.  The  alveolar  portion  of  the  upper 
and  lower  maxillary  bones,  together  with  the  teeth  which  are  inserted 
there,  divide  it  into  two  halves,  an  anterior,  which  is  smaller,  and  which 
may  be  called  the  vestibule  of  the  oral  cavity,  and  the  posterior,  which 
is  larger.  The  first  is  included  between  the  alveolar  processes  and 
the  lips  ; the  second  is  situated  behind  the  alveolar  arches.  These 
two  halves  are  perfectly  separated  from  each  other  when  the  jaws  are 
closed  by  the  two  rows  of  teeth  which  touch  and  fit  each  other  from 
before  backward.  When  perfectly  at  rest  the  posterior  half  contains 
the  tongue  and  receives  the  excretory. ducts  of  the  inferior  salivary 
glands,  while  those  of  the  superior  open  into  the  anterior  half.  The 
oral  cavity  is  covered  on  the  outside  by  the  common  integuments,  below 
which  are  the  bones  and  muscles,  then  the  buccal  membrane  {mem- 
brana  oris),  which  envelopes  every  part  of  it. 

The  buccal  membrane  in  fact  begins  at  the  upper  part  of  the  ex- 
ternal faces  of  the  lips,  where  the.skin  suddenly  becomes  softer,  thinner, 
and  redder. 


200 


DESCRIPTIVE  ANATOMY. 


It  lines  all  the  parts  which  circumscribe  the  cavity  of  the  mouth, 
so  that  it  perfectly  closes  the  openings  in  the  bony  portion  of  the 
palate,  the  anterior  and  posterior  palatine  foramina.  Around  the 
alveoli  it  is  uninterruptedly  continuous  with  the  membrane  which 
covers  them. 

It  forms  folds  in  several  places.  Four  of  these  folds  are  situated  on 
the  median  line.  The  two  most  anterior  exist  between  the  centre  of 
the  anterior  faces  of  the  two  maxillary  bones  and  the  upper  and 
lower  lips.  They  are  both  termed  the  frena  of  the  lips  ( frenu- 
lum labii  superioris  et  inferioris).  The  upper  is  much  more  distinct 
than  the  lower,  which  generally  is  hardly  visible.  The  third  is  si- 
tuated between  the  posterior  face  of  the  lower  jaw  and  the  anterior 
part  of  the  inferior  face  of  the  tongue  ; it  is  called  the  frehum  of  the 
tongue  ( frenulum  lingua). 

When  too  long  or  too  short  it  is  equally  unfavorable  to  deglutition 
and  speaking. 

The  fourth  extends  from  the  posterior  extremity  of  the  upper  face  of 
the  tongue  to  the  middle  of  the  anterior  face  of  the  epiglottis. 

The  buccal  membrane  also  forms  : 

1st.  Two  lateral  folds,  which  extend  from  the  upper  face  of  the 
tongue  to  the  edges  of  the  epiglottis,  where  they  terminate. 

2d.  Two  lateral  folds,  situated  on  the  anterior  part,  which  extend 
from  the  alveolar  edge  of  the  two  jaws  to  the  inner  face  of  the  ramus 
of  the  lower  jaw. 

3d.  Two  other  lateral  folds,  which  cover  the  two  arches  of  the  soft 
palate. 

Of  these  folds  the  most  remarkable  are  those  on  the  median  line,  as 
they  make  a part  of  the  septum  which  extends  all  along  the  body. 

The  texture  of  the  buccal  membrane  is  not  the  same  in  every  part 
It  however  always  presents  two  general  characters  : 

1st.  It  is  covered  in  every  part  by  a soft,  thick,  and  moist  epi- 
dermis. 

2d.  It  presents  almost  in  every  part  single  and  large  muciparous 
glands. 

II.  DIFFERENCES  DEPENDENT  ON  DEVELOPMENT. 

§ 2046.  The  form  of  the  oral  cavity  changes  remarkably.  In  the 
early  periods  of  life  it  is  proportionally  shorter  from  before  backward, 
especially  at  its  lower  part,  than  when  the  subject  is  fully  grown.  At 
this  time  the  lips  do  not  exist,  so  that  the  oral  cavity  is  uninterruptedly 
continuous  with  the  face,  and  its  roof,  the  palate,  not  being  closed,  it  is 
blended  with  the  nasal  fossæ,  toward  the  upper  part  of  which  is  the 
tongue,  then  proportionally  very  large.  This  horizontal  septum  is 
gradually  developed  from  before  backward  by  the  union  on  the  median 
line  of  the  palatine  portions  of  the  superior  maxillary  and  the  palatine 
bones,  and  also  the  soft  palate  on  each  side.  This  union  is  rarely 


OF  THE  DIGESTIVE  SYSTEM. 


201 


perfect  before  the  third  month  of  fetal  existence.  The  soft  palate  is 
perfect  on  the  median  line  even  before  its  two  lateral  parts  are  tho- 
roughly united  posteriorly,  and  the  uvula  descends  from  their  centre 
between  them  as  an  entirely  distinct  and  separate  appendage.  This 
soft  palate  is  at  first  very  broad,  presents  no  appearance  of  an  appen- 
dage, and  is  divided  in  its  whole  extent  into  two  lateral  halves.  This 
division  soon  disappears,  and  at  the  same  time  the  two  lateral  halves 
of  the  soft  palate  approach  each  other  still  nearer,  and  thus  push  the 
uvula  a little  forward,  so  that  it ‘covers  the  small  fissure  still  existing 
in  the  anterior  region  of  the  palate.  At  this  time  its  upper  part  is 
united  to  the  two  lateral  halves,  and  the  inferior  passes  downward  a 
little  below  it,  Finally  the  two  halves  of  the  soft  palate  completely 
unite  with  each  other  and  with  the  uvula,  and  the  formation  is  com- 
pleted by  the  gradual  prolongation  of  the  latter.  The  perfect  union  of 
the  uvula  with  the  soft  palate  occurs  at  the  middle  or  end  of  the  fourth 
month  of  pregnancy.  The  uvula,  however,  until  the  end  of  the  fifth 
month  continues  to  be  bifurcated,  compared  with  its  state  in  the  adult, 
although  it  is  united  on  each  side  with  the  soft  palate,  so  that  perhaps 
this  period  of  its  development  is  frequently  extended  beyond  the  usual 
time,  although  terminated  before  the  end  of  gestation. 

III.  ABNORMAL  STATE. 

§ 2047.  The  most  remarkable  abnormal  state  of  the  cavity  of  the 
mouth  is  when  its  primitive  formation  continues,  that  is,  when  it  com- 
municates with  the  face  and  nasal  fossæ,  and  the  primitive  fissures  are 
not  obliterated.  This  state  of  the  upper  lip  is  termed  liare-lip , and  that 
of  the  arch  of  the  palate  is  termed  fissure  of  the  palate. (1)  Generally 
then  the  solution  of  continuity  in  the  lip  or  palate,  excepting  in  the 
uvula,  does  not  correspond  to  the  median  line,  but  occurs  on  one  of  the 
two  sides,  since  it  is  situated  also  like  the  fissures  by  which  the  lips 
communicated  primitively  with  the  face.  Farther,  in  the  simple  fissure 
of  the  palate  we  generally  remark  that  the  anterior  and  intermaxillary 
portion  of  the  upper  maxillary  bone  on  one  side  is  separated  from  the 
posterior  ; at  least  the  solution  of  continuity  is  rarely  situated  on  the 
median  line,  and  the  intermaxillary  bones  are  seldom  attached  each  to 
the  corresponding  maxillary  bone,  and  the  two  maxillary  bones  with 
the  'palatine  bones  are  not  often  separated  symmetrically  from  each 
other  and  from  the  septum  of  the  nasal  fossæ. (2)  The  mode  in  which 
the  uvula  is  developed  explains  why  fissures  in  it  are  situated  on  the 
median  line. 

(1)  Sandifort,  De  labio  leporino  congenito,  duplici  el  complicata  ; in  the  Obs,  anal, 
pathol.,  book  iv.,  ch.  iii. — Tenon,  Sur  quelques  vices  de  la  voûte  palatale;  in  liis 
Mém.  et  obs.  sur  V anatomie,  Paris,  1810,  p.  296. 

(2)  Tenon,  loc.  cit.,  obs.  i. 


202 


DESCRIPTIVE  ANATOMY 


It  13  curious  that  however  great  this  deviation  of  formation,  it  some- 
times disappears  at  a more  advanced  period,  and  assumes  the  normal 
conditions  of  the  regular  type  ; the  bony  palate  increases  either  alone 
or  after  the  hare-lip  is  united,  and  the  space  between  the  oral  and 
nasal  cavities  gradually  fills  up.  This  fact  supports  our  previous  con- 
jecture that  the  two  halves  of  the  uvula  sometimes  unite  in  the  fetus 
after  the  usual  period  of  union. 

The  oral  cavity  presents  those  alterations  of  texture  observed  in  all 
the  mucous  membranes.  One  of  the  rarest  anomalies  of  this  class  is 
the  development  of  hairs,  which  have  been  observed  once  on  the  sur- 
face of  an  encysted  tumor  in  the  fauces  of  a newly  born  infant.(l) 
It  has  been  asserted  that  they  have  been  seen  also  on  the  tongue. (2) 

B.  TARTS  WHICH  COMTOSE  THE  ORAL  CAVITY. 

§ 2048.  The  different  regions  of  the  oral  cavity  are  : 

1st.  The  lips. 

2d.  The  cheeks. 

3d.  The  palate. 

We  proceed  to  describe  also  : 

4th.  The  tongue. 

5th.  The  teeth. 

6th.  The  oral  salivary  glands 

1,  LIPS  AND  CHEEKS.  * 

A.  FOHM. 

§ 2049  The  lips  (labia)  are  prolongations  which  coper  the  anterior 
face  of  the  alveolar  edge  of  the  jaws,  being  parallel  with  it.  Their 
loose  edges  which  look  towards  each  other  are  more  or  less  enlarged 
and  turned  over,  that  of  the  lower  always  more  than  the  upper.  The 
opening  between  them  is  termed  the  mouth  (os). 

The  upper  lip  is  longer  and  more  prominent  than  the  lower.  We 
remark  in  it.  on  the  median  line  a longitudinal  depression  called  the  phil 
tram,  which  extends  from  the  septum  of  the  nose  to  the  place  where 
the  skin  becomes  much  thinner.  This  depression  is  remarkable  on 
account  of  the  space  which  primitively  existed  at  the  same  place  be- 
tween its  two  lateral  halves. 

In  the  lower  lip  there  is  nothing  similar,  a difference  which  should 
be  considered  : 

1st.  Because  we  know  of  no  instance  of  a fissure  of  the  lower  lip. 

(1)  Ford,  in  the  Méd.  communie ,,  vol.  i.,  no.  51- 

(2)  Amatus  Lusitanus,  Cœs.  vied.  cent.,  ch  vi.,  p 63. 


or  THE  digestive  system. 


203 


2d.  Because  the  depression  of  the  upper  lip  seems  to  depend  on  the 
greater  extent  of  the  superior  frenum,  and  on  the  separation  of  the  su- 
perior maxillary  bones,  which  always  continues  during  life. 

' The  places  where  the  two  lips  unite  are  termed  the  angles  of  the 
mouth  ( anguli  oris.) 

The  lips  are  insensibly  continuous  on  each  side  with  the  cheeks. 

Both  regions  are  formed  by  a cutaneous,  a muscular,  and  a mucous 
layer. 

B.  MUSCLES  OF  THE  LIPS. 

§ 2050.  The  different  changes  in  the  form  of  the  cavity  of  the 
mouth,  are  produced  by  the  action  of  the  following  muscles  winch 
occupy  the  regions  of  the  lips,  the  cheeks,  and  the  chin. 

a.  Orbicularis  oris. 

§ 2051.  The  orbicularis  oris  muscle,  buccal , Ch.  ( M . annularis , 
orbicularis  oris,  sphincter  oris),  principally  forms  the  fleshy  layer  of 
the  lips,  surrounds  the  mouth,  and  is  situated  between  the  skin  and 
the  mucous  membrane.  It  is  oval,  thin,  flat  and  broad,  and  is  formed 
of  concentric  fibres  The  external  blend  insensibly  with  those  of  its 
antagonists,  or  are  prolongations  of  fibres  of  these  different  muscles 
which  interlace  together.  These  external  fibres,  however,  are  distinct, 
and  are  not  blended.  The  internal  form  a separate  order.  They  are 
found  near  the  loose  inner  edge  of  the  muscle  and  of  the  bps  ; but  they 
insensibly  disappear  in  the  external  fibres. 

This  muscle  is  united  more  intimately  with  the  skin  than  with  the 
mucous  membrane.  It  contracts  and  closes  the  mouth,  and  draws  up 
its  angles. 

b.  Buccinator. 

§ 2852.  The  buccinator  muscle,  bucco-labial , Ch.,  is  situated  be- 
tween the  upper  and  lower  maxillary  bones  and  the  orbicularis  oris 
muscle.  It  is  square,  broad,  thin,  and  flat.  Its  fibres  have  generally 
a transverse  direction  ; the  upper,  however,  go  obliquely  from  above 
downward  and  from  behind  forward,  the  inferior  proceed  in  the  op- 
posite direction,  and  the  central  alone  are  straight.  Its  fixed  points 
are  the  superior  and  the  inferior  maxillary  bones.  It  arises  from  the 
external  face  of  the  alveolar  edge  of  these  two  bones  ; its  attachments 
commence  behind  the  last  molar  tooth,  and  extend  to  about  the  second 
anterior.  It  also  arises  at  its  posterior  part  from  the  summit  of  the  in- 
ternal wing  of  the  pterygoid  process,  and  from  a ligament  which  ex- 
tends from  that  point  to  the  alveolar  edge  of  the  lower  maxillary  bone. 
It  is  blended  forward  with  the  orbicularis  oris  muscle.  The  canal  of 
Steno  passes  through  it,  near  its  anterior  extremity. 


204 


DESCRIPTIVE  ANATOMY. 


It  draws  the  lips  and  the  whole  mouth  directly  backward,  contracts 
the  cavity  of  the  mouth,  and  consequently  expels  the  substances  in 
tins  cavity,  so  that  it  acts  in  blowing,  whistling,  expelling  liquids  from 
the  mouth,  sucking,  forming  the  mass  of  food  on  the  tongue,  and  in 
swallowing. 

§ 2053.  We  may  distinguish  into  upper  and  lower  the  following 
muscles  which  contribute  to  open  the  mouth. 

The  upper  are,  considering  them  from  without  inward  : 

c.  d.  Zygomatici. 

§ 2054.  The  zygomatici  muscles,  zygomato-labiaux , Ch.,  arc  two  in 
number,  a large  and  a small  (JVI.  zygomalicus  major  el  minor).  Both 
are  elongated  and  thin.  The  large  is  more  round  than  the  small,  and 
is  also  situated  further  outward  and  backward.  Both  arise  from  the 
external  face  of  the  malar  bone  ; sometimes,  however,  the  small  comes 
only  from  the  external  and  inferior  part  of  the  orbicularis  palpebrarum 
muscle,  which  generally  sends  some  fibres  to  them.  Both  go  ob- 
liquely from  above  downward,  from  without  inward,  and  from  behind 
forward.  They  blend  with  the  orbicularis  oris  muscle  ; the  small  with 
that  portion  of  this  muscle  which  makes  part  of  the  upper  lip  ; the 
large  with  that  which  extends  to  the  angle  of  the  mouth  and  to  the 
lower  lip.  • 

Sometimes  the  zygomaticus  minor  muscle  is  deficient;  in  other  cases 
its  lower  extremity  is  bifurcated  ; in  some  subjects  it  does  not  descend 
to  the  orbicularis  oris  muscle,  but  terminates  in  the  outer  face  of  the 
levator  labii  superioris  arid  the  levator  anguli  oris  muscles. 

These  muscles  draw  the  skin  of  the  cheeks,  the  commissure  of  the 
lips,  and  the  whole  mouth,  downward  and  outward.  They  conse- 
quently contribute  to  enlarge  the  mouth,  particularly  when  they  act 
on  both  sides  at  once. 

e.  Levator  anguli  oris. 

§ 2055.  The  levator  anguli  oris  muscle,  petit  sus-maxillo-labial,  Ch. 
(M.  levalor  anguli  oris , s.  caninus),  is  broader  than  the  preceding,  and 
is  flat  and  elongated.  It  arises  in  the  canine  fossa  below  the  infra- 
orbital' foramen,  descends  almost  perpendicularly,  becoming  thicker 
and  narrower,  and  blends  in  the  angle  of  the  mouth  behind  the  zygo- 
rnaticus  major  muscle  with  the  orbicularis  oris,  and  still  more  with  the 
depressor  labii  inferioris  muscle. 

It  raises  the  angle  of  the  mouth  and  the  upper  lip. 

f.  Levator  labii  super  ioris. 

§ 2056  The  levalor  labii  superioris  muscle,  moyen  sus-maxillo 
labial , Ch.,  is  much  larger  than  the  preceding,  and  partly  conceals  its 
upper  extremity,  being  covered  in  this  place  by  the  orbicularis  palpe- 


OF  THE  DIGESTIVE  SYSTEM. 


205 


brarum  ; it  has  nearly  the  same  form  but  a different  direction,  for  it 
descends  obliquely  from  without  inward.  It  arises  from  the  upper 
maxillary  bone  above  the  infra-orbitar  foramen  and  is  attached  to  about 
the  middle  of  the  upper  lip,  so  that  its  fibres  blend  with  those  of  the 
orbicularis  oris,  before  which  it  descends. 

It  draws  the  upper  lip  obliquely  upward. 

g.  Anomalus  faciei. 

§ 2057.  Below  the  preceding  and  the  levator  alæ  nasi  labiique  su- 
perioris  muscle  we  not  unfrequently  find  a long  muscle  which  arises 
near  the  canine  fossa  of  the  upper  maxillary  bone,  and  is  attached 
directly  above  the  origin  of  the  preceding  ; it  is  termed  the  anomalus 
faciei  by  Albinus  :(1)  the  rhomboideus  by  Santorini. (2) 

It  assists  to  raise  the  upper  lip,  and  wrinkles  the  skin  which 
covers  it.. 

h.  Levator  alæ  nasi  labiique  superioris. 

This  muscle  has  already  been  described. 

§ 2058.  The  lower  muscles  of  the  mouth,  considered  in  the  same 
order  as  the  preceding,  are,  the  depressor  anguli  oris,  the  depressor 
labii  inferioris,  and  the  levator  menti  muscles. 


i.  Depressor  anguli  oris. 

§ 2059.  The  depressor  anguli  oris  muscle,  maxillo-labial , Ch.,  called 
from  its  form  the  triangular  muscle  of  the  lips , arises  from  the  anterior 
part  of  the  lower  edge  and  the  anterior  face  of  the  lower  maxillary 
bone.  It  ascends,  contracting  and  becoming  thicker  towards  the  angle 
of  the  mouth,  where  it  blends  with  the  orbicularis  oris,  the  zygo- 
maticus  major,  and  particularly  the  levator  labii  superioris  muscle,  so 
as  to  form  with  this  latter  a single  muscle  very  much  contracted  in  its 
centre,  the  fibres  of  which,  however,  are  not  interrupted  by  a median 
tendon. 

When  the  lower  part  of  the  muscle  formed  by  the  union  of  the  le- 
vator labii  superioris  and  the  depressor  anguli  oris  acts  alone,  it  draws 
the  angle  of  the  mouth  and  the  lower  lip  downward,  as  in  weeping. 
This  muscle  also  enlarges  the  mouth  transversely  by  its  external 
fibres.  When  acting  alone  it  contributes  to  raise  the  lower  jaw. 

(1)  Hist,  muse .,  p.  167. 

(2)  Obs.  anal.,  ch.  i.,  § 25. 


VOL.  Ill 


27 


20G 


DESCRIPTIVE  ANATOMY 


j.  Depressor  labii  iiiferioris. 

§ 2060.  The  depressor  labii  iiiferioris  muscle,  mento-labial , Ch. 
(quadratics  menti),  is  thin  and  square.  It  is  covered  at  its  lower  part 
by  the  preceding,  and  slightly  above  by  the  base  of  the  zygomaticus 
major  muscle  ; it  arises  farther  forward  and  lower  than  the  depressor 
anguli  oris  muscle,  ascends  obliquely  from  without-  inward  towards  the 
lower  lip,  interlaces  and  intercrosses  with  that  of  the  opposite  side  by 
its  upper  and  inner  part,  and  terminates  in  the  orbicularis  oris  muscle. 

It  draws  the  lower  lip  obliquely  downward  and  turns  it  over. 

This  muscle  and  the  preceding  generally  blend  with  the  upper  part 
of  the  platysma  myoides  muscle. 

k.  Levator  menti. 

§ 2061.  The  levator  menti  muscle  is  small,  thick,  semicircular,  and 
unmated.  It  is  attached  on  each  side  to  the  anterior  face  of  the  lower 
jaw,  below  the  alveolar  process  of  the  canine  tooth,  occupies  the  trian- 
gular space  between  the  two  depressor  muscles,  and  terminates  in  the 
skin  of  the  chin. 

It  raises  the  lower  lip  and  skin  of  the  chin. 

II.  PALATE. 

A.  FORM. 

§ 2062.  The  palate  ( palatum ) forms  the  arch  of  the  mouth,  which 
it  separates  from  the  nasal  fossæ.  We  distinguish  in  it  two  portions, 
an  anterior  or  osseous  portion,  and  a posterior  or  soft  portion. 

The  osseous  palate  is  composed  of  the  horizontal  or  palatine  portion 
of  the  superior  maxillary  and  palatine  bones,  and  also  of  the  mucous 
membrane  extended  on  their  surface.  This  membrane  incloses  a layer 
of  muciparous  glands  which  is  much  thicker  and  more  complex  than 
that  of  the  two  preceding  regions. 

§ 2063.  The  soft  palate,  called  also  the  veil  of  the  palate  ( palatum 
molle , s.  velum  palatinum ),  forms  a fold  which  extends  obliquely  from 
_ above  downward  and  from  before  backward  from  the  posterior  edge  of 
the  horizontal  portion  of  the  palatine  bones  toward  the  base  of  the 
tongue.  Its  lower  edge  is  loose,  and  presents  in  the  centre  a rounded 
prolongation,  termed  the  uvula, (l)  on  each  side  of  which  is  a fissure. 
These  two  fissured  halves  of  the  lower  edge  form  the  inferior  arches  oj 
the  palate  (Jl.  palatini  inferiores).  The  superior  arches  ( A . palatini 

(1)  List'ranc,  Considérations  anaiomiqu.es,  physiologiques  cl  pathologiques  sur  la 
luette  ; in  the  Revue  médicale,  vol.  xi.,  p.  233. 


OF  THE  DIGESTIVE  SYSTEM, 


207 


supcrioves)  are  situated  a.  little  above.  Both  are  continuous  on  the 
median  line  in  the  uvüla. 

The  soft  palate  is  formed  of  two  layers  of  mucous  membrane  which 
cover  its  anterior  and  posterior  faces,  and  are  continuous  with  the  pi- 
tuitary membrane,  of  a very  dense  layer  of  muciparous  glands  situated 
between  the  two  membranes,  and  of  several  muscles  which  contract 
and  vary  the  form  of  the  isthmus  of  the  fauces  ( isthmus  faucium). 

A prominence  resembling  a cicatrix  exists  along  the  anterior  face  of 
the  soft  palate  and  the  greater  upper  part  of  the  uvula  ; this  marks 
the  primitive  division  of  this  part  into  two  halves. 

B.  MUSCLES  OP  THE  SOFT  PALATE. 

§ 2064.  The  muscles  of  the  soft  palate  are  distinguished  into  those 
which  depress  it  and  those  which  raise  it.  The  first  contract  the  isthmus 
of  the  fauces,  the  latter  dilate  it. 

The  muscles  which  contract  the  isthmus  of  the  fauces  are  situated 
in  the  two  arches  ; those  which  dilate  it  descend  from  the  base  of  the 
skull  and  are  directed  from  without  inward. 

a.  Constrictors  of  the  isthmus  of  the  fauces. 

§ 2065.  The  constrictor  muscles  of  the  isthmus  of  the  fauces  are 
two,  the  palatopharyngeus  and  the  glosso-pharyngeus  muscles. 


a.  Palato-pharynsreus. 

§ 2066.  The  palato-pharyngeus  muscle  or  the  superior  constrictor 
•of  the  isthmus  of  the  fauces  (JVf.  palalo-pharyngœus,  s.  constrictor 
isthmi  faucium  superior ) arises  from  the  upper  part  of  the  lateral  wall 
of  the  pharynx,  where  its  fibres  blend  with  those  of  the  superior  and 
middle  constrictors.  Thence  it  enlarges,  goes  upward  and  inward, 
enters  the  soft  palate,  divides  into  an  anterior  and  a posterior  layer, 
which  receive  between  them  the  levator  palati  mollis  muscle,  extends 
to  the  posterior  extremity  of  the  bony  palate,  and  unites  on  the  median 
line  with  that  of  the  opposite  side. 

It  depresses  the  soft  palate. 

b.  Glosso-pharyngeus  muscle. 

§ 2067.  The  glosso-pharyngeus  muscle,  of  the  inferior  constrictor 
of  the  isthmus  of  the  fauces  {M.  glosso-pharyngceus,  s.  constrictor 
isthmi  faucium  minor,  s.  inferior,  s.  proprim ),  a similar  but  much 
smaller  muscle,  ascends  from  the  root  of  the  tongue  in  the  soft  palate 
before  the  palato-pharyngeus  muscle,  with  which  it  unites  and  arrives 


208 


DESCRIPTIVE  ANATOMV. 


at  the  lowev  arch,  where  it  joins  with  that  of  the  opposite  side  at  the 
base  of  the  uvula. 

It  depresses  the  soft  palate,  and  particularly  the  uvula. 

b.  Muscles  which  dilate  the  isthmus  of  the  fauces. 

§ 2068.  There  are  two  muscles  also  which  dilate  the  isthmus  of  the 
fauces,  the  levator  and  the  tensor  palati  mollis  muscles. 

a.  Levator  palati  mollis. 

§ 2069.  The  levator  palati  mollis  muscle  (JVT.  levator  palati  mollis, 
s.  petro-salpingo-staphylinus),  pétro-staphylin,  Ch.,  is  oblong  and  almost 
rounded  ; it  arises  from  the  centre  of  the  anterior  edge  of  the  petrous 
process,  and  from  the  osseous  portion  of  the  Eustachian  tube,  and  also 
from  the  posterior  part  of  the  commencement  of  its  cartilaginous  por- 
tion, by  a short  and  strong  tendon,  goes  inward  and  downward,  en- 
larges but  becomes  thinner,  and  blends  with  that  of  the  opposite  side  ; 
it  forms  in  the  soft  palate  between  the  two  layers  of  the  palato-pha- 
ryngeus  muscle  an  arch  the  convexity  of  which  looks  upward  and 
the  concavity  downward. 

It  raises  the  soft  palate,  and  extends  it  transversely. 

b.  Tensor  palati  mollis. 

§ 2070.  The  tensor  palati  mollis  muscle,  ptérygo  staphylin,  Ch. 
(M.  tensor  palati  mollis,  circumflexus  palati,  plerygo-salpingo-staphy- 
linus),  is  broad,  thin,  and  quadrilateral.  It  arises  a little  inward  and 
forward  from  the  upper  extremity  of  the  pterygoid  process  behind  the 
pterygoid  fossa  on  the  inside  of  the  oval  foramen  of  the  sphenoid  bone  ; 
it  frequently  comes  also  from  a greater  or  less  exteht  of  the  posterior 
edge  of  the  internal  layer  of  the  pterygoid  process,  and  from  the  outside 
of  the  cartilaginous  portion  of  the  Eustachian  tube.  It  goes  inward 
and  downward  and  becomes  a flat  tendon,  which  turns  on  the  hook  of 
the  pterygoid  process,  a mucous  bursæ  existing  between  them  ; it 
is  attached  by  its  anterior  edge  to  the  posterior  edge  of  the  palatine 
arch,  and  always  blends  with  the  tendon  of  that  of  the  opposite  side  to 
form  the  upper  part  of  the  soft  palate. 

This  muscle  extends  the  soft  palate  and  draws  it  outward,  and  con- 
tributes, like  the  preceding,  to  dilate  the  isthmus  of  the  fauces. 

c.  Palato-staphylinus. 

§ 2071.  The  uvula  or  the  central  portion  of  the  palate,  the  base  of 
which  is  pointed,  is  composed  of  numerous  muciparous  glands,  which 
are  every  where  surrounded,  sometimes  by  one  sometimes  by  two 


OF  THE  DIGESTIVE  SYSTEM. 


209 


muscles,  termed  the  palato-staphylinus  (M.  uvulœ , s.  azygos  uvulœ) 
This  muscle  is  always  very  long,  and  descends  from  the  palatine  spine 
and  the  anterior  face  of  the  tendon  of  the  tensor  palati  mollis  muscle. 
By  contracting,  it  shortens  the  uvula. 

III.  TONGUE. 

A.  NOBMAL  STATE. 

§ 2072.  The  tongue  ( lingua){\ ) is  the  principal  organ  of  taste,  and 
also  of  speech  and  deglutition. 

We  may  consider  it  as  the  lower  part  of  the  cavity  of  the  mouth, 
and  consequently  of  the  alimentary  canal,  which  is  considerably  en- 
larged, and  which  from  this  fact  projects  within  the  cavity. 

Its  form  is  oblong,  its  edges  are  rounded,  and  it  gradually  becomes 
thin  from  behind  forward. 

Its  posterior  part  is  termed  the  root,  and  the  anterior  part  the  point 
or  apex.  It  extends  forward  and  on  the  sides  much  beyond  its  base  of 
support,  so  that  it  is  loose  in  these  two  regions,  which  form  most  of  it. 
Its  integuments  are  uninterruptedly  continuous  with  the  buccal  mem- 
brane, which  forms  below  its  point  a longitudinal  fold  of  a very  firm 
tissue,  which  is  attached  to  the  centre  of  the  inner  face  of  the  lower 
maxillary  bone,  fixes  the  organ  more  firmly  to  the  part  it  occupies, 
and  is  termed  the  frcenum  linguae. 

As  the  tongue  is  formed  chiefly  by  muscles,  it  assists  in  articulation 
and  deglutition,  while  on  account  of  its  membranes  it  is  the  organ  of 
taste. . 

Its  base  is  formed  posteriorly  by  the  hyoid  bone. 

a.  Muscles  of  the  tongue. 

§ 2073.  The  muscles  of  the  tongue(2)  may  be  distinguished  into 
the  muscles  of  the  hyoid  bone  and  the  proper  muscles  of  the  tongue. 

(1)  M.  Malpighi,  De  lingua , Bologna,  1665. — G.  Fracassati,  De  lingua. — L.  Bel- 
lini, Gustus  organon  novissime  detectum,  Bologna,  1665. — L.  Heister,  De  lingua 
sana  et  œgrota,  Altdorf,  1716. — A.  F.  Walter,  De  lingua  Humana,  Leipsic,  1724. — J. 
Reverhorst,  De  fabriea  et  usu  linguae,  Leyden,  1739.— Royen,  De  fabrica  el  usu 
linguae,  Leyden,  1742. — J.  A.  Rinder, -De  linguae  involucris,  Strasburg,  1778. — 
Bauer,  Sur  la  structure  de  la  langue  ; in  the  Journal  compl.  des  sc.  méd.,  vol.  xiv., 
p.  181. — Gerdy,  Discussions  et  propositions  d'anatomie,  de  physiologie  et  de  patho- 
logie, Paris,  1823,  p.  19,  pl.  i.  and  ii. — Blandin,  Sur  la  structure  et  les  movvemens  de 
la  langue  ; in  the  Archiv,  gén.  de  méd.,  vol.  i.,  p.  437. 

(2)  Isenflamm,  De  motu  linguae,  F.rlangen,  1793. 


21.0 


DESCRIPTIVE  ANATOMY 


a Muscles  of  the  hyoid  bone 

1.  Mylo  hyoideus. 

§ 2074.  The  mylo-hyoideus  muscle  transversus  mundibulœ,  s. 
mylo-hyoideus)  fills  the  larger  anterior  part  of  the  space  between  the 
two  halves  of  the  lower  jaw,  viz.,  the  two  halves  of  the  horizontal 
portion  and  the  body  of  the  hyoid  bone.  It  is  loose  outward  in  nearly 
its  whole  extent,  and  is  covered  in  its  centre  by  the  anterior  belly  of 
the  digastricus  muscle  of  the  lower  jaw. 

It  is  a triangular  and  thin  muscle,  the  external  convex  edge  of 
which  arises  from  a corrugated  line  on  the  inner  face  of  the  horizontal 
portion  of  the  lower  jaw,  and  proceeds  from  before  backward  and  from 
within  outward.  It  enlarges  considerably  from  before  backward.  Its 
anterior  fibres  are  transverse.  The  posterior  are  directed  from  before 
backward  and  from  without  inward,  and  proceed  toward  those  of  the 
opposite  side.  It  descends  from  without  inward,  and  unites  with  the  lat- 
ter on  the  median  line,  being  separated  from  it  only  by  a narrow  tendinous 
band  which  extends  from  before  backward  to  the  single  muscle  formed 
by  this  union.  It  is  attached  by  the  inner  portion  of  its  posterior 
edge  to  the  centre  of  the  anterior  face  of  the  middle  piece  of  the  hyoid 
bone. 

This  muscle  supports  those  of  the  tongue,  which  rest  on  it,  and  also 
the  sublingual  gland,  compresses  the  canal  of  Wharton,  and  the  ex- 
cretory ducts  of  the  sublingual  gland,  sustains  these  parts,  and- raises 
the  hyoid  bone. 

2.  Genio-hyoideus. 

§ 2075.  The  genio-hyoideus  muscle  is  situated  directly  above  the 
centre  of  the  preceding,  next  to  the  synonymous  muscle  of  the  opposite 
side.  It  has  the  form  of  a very  elongated  triangle,  and  arises  from  the 
upper  part  of  the  anterior  face  of  the  body  of  the  hyoid  bone,  goes  from 
behind  forward  and  from  below  upward,  gradually  becomes  thinner 
and  rounder  as  it  ascends,  and  is  attached  to  the  lower  part  of  the  in- 
ternal mental  process  directly  above  the  mylo-hyoideus  muscle.  Its 
anterior  and  posterior  attachments  are  by  very  short,  tendinous  fibres. 

It  draws  the  hyoid  bone  upward  and  forward.  When  this  bone  is 
fixed  by  its  depressor  muscles  it  brings  the  lower  jaw  downward 
and  backward,  so  that  it  acts  like  the  digastricus  muscle  of  the  lower 
jaw. 

Sometimes  it  is  deficient,  or  rather  it  is  imperfectly  developed,  and 
is  replaced  by  a smaller  muscle,  which  arises  from  the  median  tendon 
of  the  preceding,  and  is  attached  to  the  digastricus  muscle.(l) 

(1)  Duille,  Far.  muse.,  Landshut,  1815,  p.  5. 


Oj?  THE  DIGESTIVE  SYSTEM 


2 iî 


3.  Stylo-hyoideus. 

§ 2076.  The  stylo-hyoidèus  muscle  (JVT.  stylo-hyoideus,  s.  levator 
ossis  hyoidei)  is  thin,  elongated,  and  rounded.  It  arises  bj  a short 
tendon  at  about  the  centre  of  the  external  face  of  the  styloid  process, 
goes  forward,  downward,  and  inward,  presents  near  its  lower  extremity 
a fissure  for  the  tendon  of  the  digastricus  muscle,  and  is  attached  to 
the  anterior  half  of  the  external  edge  of  the  large  horn  of  the  hyoid 
bone  opposite  the  thyro-hyoideus  muscle. 

It  chaws  the  hyoid  bone  upward  and  backward. 

It  is  frequently  doubled,  which  anomaly  depends  on  the  presence  of 
a small  accessory  muscle. 

4.  Sterno-hyoideus. 

§ 2077.  The  sterno-hyoideus  muscle  (JVT.  depressor  ossis  hyoidei , s. 
sterno-hyoideus ) is  thin  and  elongated.  It  conies  from  the  inner  face 
of  the  first  piece  of  the  sternum  and  of  that  of  the  cartilage  of  the  first 
rib,  and  sometimes  also  from  the  inner  extremity  of  the  clavicle  ; 
thence  it  goes  directly  upward,  in  its  course  approaching  that  of  the 
opposite  side,  and  becomes  thicker  and  narrower.  It  is  finally  attached 
to  the  lower  edge  of  the  middle  piece  of  the  hyoid  bone,  directly  at  the 
side  of  the  median  line. 

It  draws  the  hyoid  bone  downward,  and  as  this  bone  is  attached 
to  the  lower  jaw,  when  the  other  is  not  fixed  by  its  levator  muscles,  it 
is  also  depressed  so  that  it  acts  on  opening  the  mouth. 

Sometimes  it  blends  below  with  the  sterno-thyroideus  muscle,(l)  or 
arises  from  the  centre  of  the  clavicle. (2) 

5.  Omo-hyoideus. 

§ 2078.  The  omo-hyoideus  muscle,  scapulo-hyoidien , Ch.  (JYI.  re- 
tractor ossis  hyoidei , omo-hyoideus , coraco-hyoideus ),  is  a very  long, 
thin,  and  digastric  muscle.  Its  inferior  belly  arises  from  the  upper  edge 
of  the  scapula,  sometimes  also  from  the  small  ligament  extended  over 
the  coracoid  fissure  ; goes  upward  and  forward  ; between  the  sterno- 
cleido-mastoideus  and  the  scalenus  anticus  muscles  it  becomes  a 
tendon  whence  the  superior  belly  arises,  which  is  attached  to  the 
middle  piece  of  the  hyoid  bone  on  the  outside  of  the  preceding,  and 
blends  more  or  less  with  the  stylo-hyoideus  muscle. 

It  draws  the  hyoid  bone  downward,  backward,  and  a little  to  the 
side.  This  muscle  frequently  presents  anomalies.  It  is  rarely  entirely 

(1)  Albinus,  HistjUnusc.,  p.  202. 

(2)  Kcleh,  Bcytrage  zur  pat  hol.  Amt.,  Berlin,  1714,  p.  32. 


212 


DESCRIl’lT  VJJ  ANATOMY. 


deficient  : we  have  observed  it  once,  on  the  left  side,  without  a substi- 
tute. Its  origin  frequently  varies.  Sometimes  the  inferior  belly  is 
broader,  so  that  it  extends  to  the  upper  angle  of  the  scapula.(l) 
Sometimes  it  arises  from  the  clavicle,^  2)  and  it  is  then  unusually 
short.  In  some  subjects  the  lower  belly  is  divided  into  two  heads,  to 
which  its  simple  enlargement  is  an  approximation. (3)  One  of  these 
heads  is  sometimes  attached  to  the  clavicle.  (4)  In  some  cases  it 
unites  with  the  sterno-thyroideus  muscle  by  its  superior  belly  or  by 
a special  head. (5)  More  rarely  it  is  not  inserted  in  the  hyoid  bone 
but  in  the  transverse  process  of  the  sixth(6)  or  second  ? cervical(7)  ver- 
tebra. 

b.  Proper  muscles  of  the  tongue. 

1 . Genio-glossus  muscle. 

§ 2079.  The  genio-glossus  muscle  (JVl.  txpulsor , utlrahens  linguae, 
s.  genio-glossus),  the  largest  of  all  the  muscles  of  the  tongue,  arises 
from  the  lower  jaw  by  tendinous  fibres  which  aïe  inserted  directly 
above  the  genio  hyoideus  muscle.  It  is  situated  against  that  of  the 
opposite  side,  which  it  does  not  leave  because  its  direction  is  that  of  the 
median  line  ; it  goes  backward,  enlarges  much  like  a fan,  and  forms 
the  greater  inner  part  of  the  tongue  the  whole  length  of  this  organ.  It 
also  gives  off  some  fibres  which  go  outward,  pass  on  the  following 
muscle,  sends  several  to  the  upper  part  of  the  pharynx,  and  furnishes 
a few  to  the  upper  horn  of  the  hyoid  bone  and  the  epiglottis. 

It  brings  the  tongue,  the  hyoid  bone  and  the  pharynx  forward. 

2.  Hyo-glossus. 

§ 2080.  The  hyo-glossus  muscle  (JVT.  depressor  linguae,  s.  hyo- 
glossus,  s.  basio-cerato-chondro-glossus)  is  thin,  and  has  a long  square 
form.  It  arises  from  the  outer  part  of  the  body  of  the  bone,  from  the 
external  edge  of  its  great  horn,  and  from  the  summit  of  the  small 
horn,  ascends  toward  the  lateral  part  of  the  tongue,  and  contributes 
to  form  it. 

It  draws  the  tongue  downward. 

(1)  Albinus,  Hist,  muse.,  p.  200. 

(2)  Albinus,  loc.  cit.,  p.  201. 

(3)  Duille,  loc.  cit.,  p.  11. 

(4)  Kelch,  loc.  cit.,  p.  31. — Sels,  De  musc,  variet.,  Berlin,  p.  6. 

(5)  Sels,  loc.  cit.,  p.  5. 


OF  THE  DIGESTIVE  SYSTEM. 


213 


3.  Stylo-glossus. 

§ 2081.  The  stylo-glossus  muscle  (JVE.  retractor  linguae , s.  stylo- 
glossus),  the  shortest  of  the  small  muscles  which  come  from  the  hyoid 
bone,  arises  directly  from  its  summit  and  also  from  the  upper  part  of 
its  circumference,  and  arrives  at  the  root  of  the  tongue,  in  which  it 
expands  like  a fan  to  its  point,  interlacing  more  or  less  with  the  hyo- 
glossüs  and  the  genio-glossus  muscles. 

It  draws  the  tongue  obliquely  backward  to  its  side,  and  enlarges  it 
when  it  acts  with  its  synonymous  muscle. 

We  have  once  found  it  double  on  both  sides. 

4.  Lingualis. 


§ 2082.  The  lingualis  muscle  is  thin  and  narrow.  It  extends  from 
before  backward  the  whole  length  of  the  tongue,  and  interlaces  prin- 
cipally with  the  hyo-glossus  and  the  genio-glossus  muscles. 

It  shortens  the  tongue,  and  carries  its  point  backward. (1) 


(1)  Gerdy  has  described  better  than  any  one  before  him  the  lingual  portion  of  the 
special  muscles  of  the  tongue,  and  has  followed  them  through  its  whole  extent.  His 
conclusions  are  as  follow  : 

The  tongue  is  composed  of  a membrane,  a peculiar  yellow  tissue,  a superficial 
lingual,  two  deep  lingual,  the  transverse  lingual,  and  the  vertical  lingual  muscles, 
all  of  which  are  distinct,  of  the  two  stylo-glossi,  the  two  liyo-glossi,  the  two  genio- 
glossi,  the  two  glosso-staphylini  muscles,  and  the  fasciculi  of  the  hyo-glosso-epi- 
glossus. 

The  lingual  membrane  is  thick  and  cartilaginous  on  its  lower  surface,  in  which 
the  subjacent  muscular  fibres  are  inserted. 

The  yellow  tissue  covers  at  the  base  of  the  tongue  the  enveloping  membrane,  which 
has  no  cartilaginous  texture  in  this  place.  It  adheres  to  the  hyoid  bone,  to  the  epi- 
glottis, and  to  many  muscular  fibres.  Follicles  exist  within  it. 

The  superficial  lingual  muscle  covers  the  upper  face  and  the  edges  of  the  tongue, 
adheres  closely  to  its  membrane,  and  is  attached  posteriorly  to  the  yellow  tissue.  Its 
fibres  go  forward,  some  on  the  upper  face  of  the  tongue,  converging:  toward  the 
median  line,  others  above  and  below  its  edges  to  its  apex. 

The  deep  lingual'muscles  are  two  small  fasciculi  situated  on  each  side  under  the 
posterior  two  thirds  of  the  tongue,  between  the  hyo-glossi  and  the  genio-glossi 
muscles.  Their  fibres  are  attached  posteriorly  to  the  yellow  tissue. 

The  transverse  lingual  muscles  are  situated  under  the  superficial  lingual,  pass 
through  the  whole  breadth  of  the  tongue  and  between  the  lateral  fibres  of  the  su- 
perficial lingual  muscle,  which  they  cross  at  a right  angle,  and  are  attached  to  the 
membrane  of  the  tongue  under  the  edge  of  this  organ.  They  are  divided  on  the 
median  line  by  a fibro-cellular  raphe.  They  gradually  curve  more  and  more  to- 
wards the  base  of  the  tongue. 

The  vertical  lingual  muscles  extend  from  the  upper  to  the  lower  lingual  mem- 
brane, passing  through  the  whole  thickness  of  the  tongue  and  the  transverse  lingual 
muscles,  with  which  they  intercross.  They  curve  and  become  more  and  more 
oblique  toward  the  base  of  the  organ. 

The  fibres  of  the  stylo-glossi  muscles  blend  with  those  of  the  superficial  lingual 
muscle  above  and  below  the  edges  of  the  tongue,  and  send  a transverse  fasciculus 
under  the  yellow  tissue,  which  unites  to  that  of  the  opposite  side. 

The  hyo-glossi  muscles  are  situated  between  the  stylo-  and  the  genio-glossi.  Their 
anterior  fibres  are  directed  from  the  hyoid  bone  very  obliquely  upward  and  forward 

Vol.  III.  28 


214 


DESCRIPTIVE  ANATOMY. 


b.  Envelops  of  the  tongue.(I) 

§ 20S3.  The  mucous  membrane  which  covers  the  tongue  is  charac- 
terized principally  by  the  great  development  of  its  papillary  tissue,  and 
by  the  facility  with  which  the  epidermis  is  detached  from  it. 

The  dermis  is  united  to  the  muscular  membrane  more  intimately 
than  with  the  subjacent  parts  in  any  other  region  of  the  body. 

Its  upper  face  is  extremely  corrugated.  The  inequalities  there  ob- 
served are  : 

1st.  Folds.  These  folds  are  seen  principally  on  the  posterior  part 
and  on  the  edges  of  the  tongue.  They  are  generally  arranged  regu- 
larly, converge  from  without  inward  and  from  before  backward,  and 
are  very  compact.  They  are  about  half  a line  high  and  broad.  The 
anterior  present  numerous  transverse  grooves.  The  posterior  are 
smooth,  and  consequently  their  surface  is  less  extensive  than  that  of 
the  preceding.  Those  at  the  most  anterior  part  of  the  tongue  are  less 
regular  and  constant.  In  the  middle  of  the  back  of  the  tongue  there 
is  frequently  a more  or  less  evident  longitudinal  depression. 

2d.  Papillæ. (2)  The  papillæ  of  the  tongue  are  arranged  very  com- 
pactly, and  cover  almost  all  its  dorsal  face.  They  are  insulated  only 
at  the  root  of  the  organ,  where  also  they  enlarge  very  much. 

They  vary  much  in  form,  and  hence  have  been  reduced  into  several 
classes. 

They  are  generally  small,  thin,  triangular,  and  terminated  by  a 
blunt  or  pointed  summit. 

The  latter  are  very  much  developed  on  the  centre  of  the  tongue  for- 
ward and  on  the  edges.  They  are  termed  the  filiform  papillæ  ( papillæ 
filiformes) . 

Others  which  are  much  larger,  more  distinct  but  fewer,  do  not  exist 
in  every  part,  and  arc  enlarged  at  their  loose  extremity  into  a rounded 


to  about  the  centre  of  the  tongue.  Some  of  the  posterior  rise  perpendicularly  to  the 
base  of  the  tongue  ; others  blend  with  those  of  the  superficial  lingual  muscle  on  the 
edges  of  the  organ. 

The  genio-glossi  muscles  are  situated  side  by  side  on  the  inside  of  the  hyo-glossi 
and  the  deep  lingual  muscles  : their  fibres  radiate  from  the  malar  process  to  the 
three  posterior  fourths  of  the  tongue,  on  the  median  line,  to  the  hyoid  bone,  the 
yellow  tissue,  and  the  lingual  membrane.  They  pass  from  below  upward  through 
the  transverse  and  the  superficial  lingual  muscle,  and  curve  slightly  upward  and 
outward  in  the  thickness  of  the  tongue. 

The  glosso-staphylini  muscles  go  from  the  sides  of  the  soft  palate  on  the  edges 
of  the  tongue,  where  they  blend  with  the  superficial  lingual  and  the  stylo-glossus 
muscle. 

The  hyo-glos30  epiglossus  is  formed  of  small  fasciculi,  generally  deficient  in  man, 
which  go  from  the  hyoid  bone  to  the  yellow  tissue,  others  from  this  tissue  to  the 
epiglottis,  others  also  from  the  epiglottis  to  the  hyoid  bone.  F.  T. 

(1)  J.  A.  Rinder,  Dc  lingua:  involucris , Strasburg,  1778. 

(2)  Albinus,  Dc  diversitate  papillarum  lingua:  humanœ  ; in  the  Annotât,  acad., 
book  i.,  cli.  xiv.— Sccmmerring,  Inc.  cit,  tab.  i.,  fig.  1-3. 


OF  THE  DIGESTIVE  SYSTEM 


215 


head,  whence  they  are  termed  the  conical  or  fungiform  papillæ  (papil- 
læ  fungif ormes,  s.  clavatœ). 

We  must  however  remark,  that  in  this  respect  they  are  frequently 
replaced  by  single  filiform  papillæ,  which  are  longer  and  larger  than 
the  others.  The  fungiform  papillæ  lead  to  the  largest  of  the  papillæ 
of  the  tongue,  which  are  situated  at  the  base  of  the  organ,  vary 
much  in  number  and  size,  and  are  arranged  in  two  oblique  series, 
which  touch  at  one  of  their  extremities,  and  thus  form  a V,  the  point 
of  which  looks  backward.  Their  form  is  generally  but  not  always 
conical,  so  that  they  enlarge  considerably  from  their  base  to  their  ex- 
tremity. They  are  situated  in  a depression  which  is  continuous  with 
the  surface  of  the  tongue  by  a sack  with  reversed  edges.  They  are 
termed  ihelenticular  papillæ  (papillæ  truncatœ,capitatœ,circumvallatœ')  : 
they  are  from  three  to  twenty  in  number.  Each  depression  commonly 
contains  only  one,  but  sometimes  three  or  four,  although  this  circum- 
stance has  no  effect  on  their  whole  number  or  on  their  size.  They  are 
not  arranged  symmetrically,  although  generally  there  is  one  which 
corresponds  very  nearly  to  the  median  line,  and  forms  the  point  of 
the  V. 

This  latter  occupies  the  deepest  of  all  the  cavities,  that  which  is 
termed  the  lacuna , the  foramen  cæcum  of  the  tongue  ; beside  which 
there  is  another  situated  behind  it,  and  which  incloses  no  papillæ. 

We  have  several  times  thought,  but  wrongly,  that  we  have  disco- 
vered in  this  foramen  cæcum  the  excretory  ducts  either  of  the  salivary 
glands  or  of  the  thyroid  gland.(l) 

§ 2084.  The  papillæ  of  the  tongue  appear  to  the  naked  eye,  and 
frequently  when  viewed  by  the  microscope  before  they  are  injected, 
smooth  in  their  whole  extent  and  single  ; but  when  their  vessels  are 
injected,  their  surface  presents  several  small  asperities,  which  seem 
formed  by  collections  of  several  fasciculi  or  filaments,  placed  one 
against  another.  This  texture  is  more  apparent  in  the  larger  and  an- 
terior, than  in  the  smaller  and  posterior  part. 

Each  filament  contains  at  least  one  vessel  ; and  when  well  injected, 
the  whole  surface  of  the  tongue  becomes  red.  These  vessels  form 
very  complex  arches  and  plexuses  on  the  surface  of  the  papillæ,  since 
they  frequently  anastomose,  and  their  loose  extremities  incline  toward 
each  other. 

Each  filament  is  also  composed  of  a soft  and  whitish  mass  which 
probably  contains  nervous  substance.  At  least  some  filaments  of  the 
glosso-pharyngeal  nerve  have  been  traced  into  the  posterior  papillæ  of 
the  tongue,  and  some  filaments  of  the  lingual  branch  of  the  fifth  pair 
into  the  others. 


(1)  Coschwitz,  Dc  ductu  salivali  novo , Halle,  1724. — Refuted  by  Duvernoy  ( De 
ductu  salivali  Coschw.,  Tubingen,  1725),  ancl  by  Haller  {E.vp.  et  dub,  circa  ductum 
Cosclno.,  Leyden,  1727). 


216 


DESCRIPTIVE  ANATOMY. 


The  arrangement  of  the  vessels  is  more  apparent  in  the  anterior 
than  in  tho  posterior  papillæ  of  the  tongue,  because  they  inclose  pro- 
portionally more  mucous  tissue. (1) 

§ 2085.  Behind  the  lenticular  papillæ,  the  surface  of  the  tongue  is 
smooth,  presenting  only  numerous  muciparous  glands  ; its  sides  are  also 
smooth.  We  only  remark  on  the  limit  between  them  and  the  lower 
part  of  the  cavity  of  the  mouth,  the  orifices  of  the  excretory  canals  of 
the  submaxillary  gland. 

§ 2086.  The  tongue  is  covered  in  every  part,  especially  on  its  upper 
face,  by  a thick,  whitish  and  moist  epidermis,  (periglottis)( 2),  which  is 
formed  exactly  like  the  papillary  tissue,  and  which  consequently  pre- 
sents on  its  upper  face  numerous  elevations,  and  on  its  lower  face, 
which  looks  towards  the  papillæ,  a corresponding  number  of  rounded 
depressions,  so  that  at  first  glance  it  seems  perforated  with  foramina, 
although  this  is  not  the  case. 

§ 2087.  We  have  already  described  the  nerves  of  the  tongue,  and 
have  given  our  reasons  for  thinking  the  lingual  twig  of  the  fifth  pair 
is  the  principal  conductor  of  the  sensations  of  taste,  while  the  hypo- 
glossal nerve  should  be  considered  as  only  the  nerve  of  motion. 

Although  the  tongue  receives  many  nerves,  and  although  its  surface 
is  very  sensible,  its  substance  is  but  slightly  so.  This  explains  how  it 
can  be  very  much  bruised,  or  how  considerable  portions  of  it  may  be 
tied,  without  giving  rise  to  general  nervous  affections. (3) 

§ 2088.  The  tongue  is  the  principal  organ  of  taste;  it  acts  also  in 
articulation,  and  contributes  to  the  first  changes  of  the  food  in  the  ali- 
mentary canal. 

The  faculty  of  taste  resides  principally  at  its  point,  next  on  its 
edges,  finally  at  its  base,  and  very  slightly  or  not  all  in  its  centre.  It 
however  is  not  the  only  organ  of  taste,  for  the  soft  palate  is  sensible,  at 
least  to  certain  tastes,  for  instance  that  of  bitter  substances.  Hence 
why  the  loss  of  the  tongue  is  not  necessarily  attended  with  that  of 
taste. 

The  tongue  assists  also  in  articulation,  inasmuch  as  several  conso- 
nants hence  termed  lingual , are  formed,  or  at  least  articulated  more 
distinctly,  by  its  motions  in  different  directions. 

It  also  contributes  to  change  the  food  in  the  mouth  by  carrying  it  to 
different  parts  of  this  cavity,  so  that  it  becomes  perfectly  moistened 
with  the  saliva,  and  also  prevents  its  escape  from  the  mouth. 

We  shall  return  to  this  use  of  the  tongue,  and  shall  mention  its  part 
in  deglutition  when  describing  the  pharynx.  ■ 


(1)  Albinus,  De  fabrica  papillarum  lingUœ  humanœ  ; in  the  Annot.  acad.  1.  i.  c. 
xv.  tab.  1. — Hewson  (Exp.  Inq.,  vol.  ii.  p.  186. — Scemmerring,  loc.  cit.,  tab.  1., 
fig.  6-9. 

(2)  Albinus,  Dc  pcriglottide  et  corpore  rcticulari  linguae;  in  the  Annot.  acad.  1.  i. 
c.  xvi. 

(3)  E.  Home,  Obs.  on  the  structure  on  the  tongue , illustrated  by  cases  in  which  a 
portion  of  that  organ  had  been  removed  by  ligature  ; in  the  Phil,  tr.,  1805,  p.  205-214. 


OF  THE  DIGESTIVE  SYSTEM, 


217 


§ 2089.  The  changes  in  the  tongue  during  its  development  are  tri- 
fling. At  first  its  proportional  volume  is  greater  than  when  the  or- 
ganism is  perfect.  It  is  also  broader,  and  is  attached  to  the  lower  wall 
of  the  cavity  of  the  mouth  in  a smaller  portion  of  its  lower  face,  which 
resembles  to  a certain  extent  the  peculiar  formation  of  frogs. 

Br  ABNORMAL  STATE. 

§ 2090.  Sometimes  the  tongue  does  not  exist,  either  from  primitive 
deviations  of  formation,  or  from  ulcers  which  have  destroyed  it. 

Its  frenum  is  not  unfrequently  too  solid,  too  short,  or  too  long.  It 
is  rarely  bifurcated  at  its  point. 

The  lenticular  papillae  also  are  rarely  entirely  deficient,  and  replaced 
only  by  skin  destitute  of  papillæ.(l) 

The  excess  in  the  size  of  the  tongue  is  rarely  congenital.  It  is  ob- 
served more  frequently  during  life  after  some  accident,  particularly 
from  metastasis. 

In  this  case  a portion  of  the  organ  may  be  extirpated  without  incon- 
venience. This  phenomenon  seems  to  affect  females  more  frequently 
than  males. 

The  turning  of  the  tongue  backward,  which  produces  suffocation  by 
closing  the  entrance  of  the  larynx,  may  be  caused  by  its  frënum  being 
entirely  divided.(2) 

The  principal  alterations  of  the  texture  of  the  tongue  are  scirrhus 
and  cancer. 


IV.  ORAL  GLANDS. 

A.  ABNORMAL  STATE. 

§ 2091.  The  oral  glands  ( Gl . orales)  are  of  two  kinds,  the  mucipa- 
rous  and  the  salivary  glands. 


a.  Muciparous  Glands. 

§ 2092.  The  muciparous  glands  are  distinguished  into  the  anterior 
and  the  posterior. 

The  anterior  are  more  insulated  and  lenticular.  Then  greatest 
diameter  is  only  two  lines,  and  they  are  found  principally  in  the  lips 
and  cheeks,  opposite  the  upper  posterior  molar  teeth,  between  the  buc- 
cal membrane  and  the  muscles  it  covers,  They  are  divided  according 

(1)  Louis,  Mémoire  'physiologique  et  pathologique  sur  la  langue  ; in  the  Mém.  de 
■Vac.  de  chir.  vol.  r.,  p.  486-520. — Breidenstein,  De  morbis  linguœ,  Erlangen,  1791. 

(2)  We  doubt  whether  death  is  ever  produced  by  this  cause,  although  travelers 

often  speak  of  negroes  swallowing  their  tongues.  Superficial  observers  have  been 
led  into  error  by  a phenomenon  which  is  proved  possible  by  Bourdon’s  researches, 
in  giving  reason  to  think,  that  the  greatest  effort  in  a robust  person  would  cause 
death,  and  thus  in  some  measure  one  commit  suicide.  ( Recherches  sur  le  mécanisme 
de  la  respiration  et  sur  la  circulation  du  sang , Paris,  1820,  p.  84.)  F.  T. 


218 


DESCRIPTIVE  ANATOMY. 


to  their  situation  into  labial,  buccal,  and  molar  ( gl . labiales,  buccales, 
et  molares ).  These  latter  are  rarely  blended  in  one  mass,  the  excre- 
tory passages  of  which  unite  in  one. 

The  posterior  are  the  palatine  glands  and  the  amygdalae. 

The  palatine  glands  (gl.  palatincz ) form  a continuous  layer  from 
one  to  two  lines  thick,  which  covers  all  the  palatine  arch  and  all  the 
soft  palate,  the  posterior  face  of  which  they  occupy. 

The  amygdalae  or  the  tonsils  (Amygdalae,  s.  tonsillœ)  are  oval  bodies, 
about  six  lines  long,  three  thick  and  broad,  which  exist  in  the  soft  pa- 
late between  the  anterior  and  posterior  arches.  The  fluid  they  secrete 
enters  the  cavity  of  the  mouth  through  several  broad  openings,  situated 
on  their  anterior  face. 


b.  Salivary  Glands. 

§ 2093.  The  three  oral  salivary  glands  (gl.  salivates  orales ) which 
belong  to  the  class  of  conglomerate  glands(l)  are  situated  around 
the  cavity  of  the  mouth  and  near  the  lower  jaw.  They  are  the  pa- 
rotid, the  submaxillary,  and  the  sublingual  glands.  All  secrete  a pe- 
culiar fluid,  the  saliva, (2)  which  is  one  of  the  most  aqueous  fluids  of 
the  body,  and  contains  a peculiar  principle  which  cannot  be  coagulated 
by  boiling,  by  tannin,  or  by  the  acetate  of  lead.  We  also  find  in  it  a 
white  mucous  substance,  and  the  common  salts  of  the  serum  of  the 
blood.  It  is  also  remarkable  for  its  great  affinity  for  oxygen.(3) 

Beside  the  general  characters  of  the  class  to  which  they  belong, 
these  glands  also  present  several  common  peculiarities,  the  principal  of 
which  are  as  follow.  1.  Their  rounded  form.  2.  Their  reddish  co- 
lor. 3.  They  have  no  special  membranous  capsule,  are  surrounded 
only  by  condensed  cellular  tissue,  and  are  loosely  attached  to  the  ad- 
jacent parts.  4.  They  are  so  situated  that  they  are  affected  by  the 
mechanical  action  of  the  muscles,  and  even  partly  by  that  of  the  lower 
jaw  when  it  is  moved.  5.  The  fluid  they  secrete  possesses  probably  in 
every  part  the  same  properties. 

Notwithstanding  these  general  points  of  resemblance,  they  differ  so 
much  in  form,  size,  texture,  situation,  and  color,  that  we  must  describe 
each  of  them  separately. 

(1)  N.  Stenon,  De  glandulis  oris  et  nuper  observatis  inde  prodeuntibus  vasis, 
Leyden,  1661.— A.  Nuck,  Sialographia  ductuwm  aquosorum  anatome  nova,  Leyden, 
1690. — J.  B.  Siebold,  Historia  Systematis  salivalis  physiologice  et  pathologice  consi- 
dérait, Jena,  1797. 

(2^  G.  T.  Fischer,  Diss.  de  saliva  physiologies  et  pathologice  considerate,  Breslau, 

1817. 

(3)  Berzelius,  Fortscritte  der  thicrischen  Chemie,  Nuremberg',  1815,  p.  47. — John, 
Recherches  chimiques  sur  la  salive  et  la  liqueur  que  les  ventricules  de  cerveau  ren- 
ferment dans  l'hydrocéphale  ; in  the  Joum,  compl.  des  sc.  méd.,  vol.  vi.,  p.  270. 


OF  THE  DIGESTIVE  SYSTEM. 


219 


a.  Parotid  gland. 

§ 2094.  The  parotid  gland  (parotis), ( 1)  is  the  largest  oral  salivary 
gland,  and  in  the  adult  it  usually  weighs  from  four  to  five  drachms. 

Its  form  is  irregularly  square.  It  is  usually  more  high  than  broad, 
narrower  from  within  outward  than  in  any  other  direction,  and  its 
thickness  is  much  less  than  its  height  and  breadth.  Its  lower  half  is 
considerably  thicker  and  broader  than  the  upper. 

It  is  situated  directly  under  the  skin,  before  the  lower  half  of  the  ex- 
ternal ear,  between  the  space  in  the  ascending  ramus  of  the  lower 
maxillary  bone  forward,  and  backward  between  the  auditory  foramen 
and  the  mastoid  process  of  the  temporal  bone. 

Its  upper  extremity,  which  is  also  the  smallest  edge,  extends  to  the 
posterior  extremity  of  the  zygomatic  arch,  and  covers  the  head  of  the 
ascending  ramus  of  the  lower  maxillary  bone.  Its  smaller  anterior 
half  corresponds  in  its  whole  extent  to  the  posterior  part  of  the  ascend- 
ing ramus  of  the  lower  maxillary  bone  and  of  the  masseter  muscle. 
The  posterior  half  is  larger  than  the  preceding,  and  fills  the  space  we 
have  mentioned.  It  covers  the  petrous  portion  and  the  styloid  process 
of  the  temporal  bone,  also  the  external  parts  of  the  pterygoidei  muscles 
and  the  upper  part  of  those  which  arise  from  the  styloid  process.  Pos- 
teriorly, the  gland  terminates  by  nearly  a straight  edge,  which  is,  how- 
ever, slightly  grooved  anteriorly.  Its  lower  extremity  descends  below 
the  angle  of  the  lower  jaw  ; it  is  in  contact  with  the  posterior  part  of 
the  submaxillary  gland,  and  with  the  middle  tendon  of  the  digastricus 
muscle. 

The  lower  straight  edge  descends  obliquely,  covers  the  posterior 
belly  of  the  digastricus  muscle,  and  also  generally  a small  portion  of 
the  upper  extremity  of  the  sterno-cleido-mastoideus  muscle. 

The  posterior  concave  edge  is  adapted  to  the  lower  part  of  the  car- 
tilaginous portion  of  the  auditory  passage. 

The  parotid  gland  is  formed  of  small,  rounded,  and  distinct  granu- 
lations. 

At  about  the  upper  extremity  of  the  middle  third  of  its  anterior  edge 
an  excretory  duct  emerges,  called  the  canal  of  Steno  ( ductus  Slenon- 
ianus)(2)  The  parietes  of  this  passage  are  considerably  thick  in 
proportion  to  its  capacity,  and  it  proceeds  from  behind  forward  and 


(1)  Murat,  La  glande  parotide  considéré  dans  ses  rapports  anatomiques  et  patho- 
logiques-,  Paris,  1803. 

(2)  Although  this  term  is  generally  applied  to  the  parotid  canal,  it  is  not  certain 
that  it  was  discovered  by  Steno,  and  not  by  Needham  or  Blaes. — N.  Steno,  Diss. 
dc  glandulis  oris  ct  nuper  observatis  inde  prodeuntibus  vasis,  Leyden,  1661. — Id., 
Obscrv.  anat.  quibus  varia  oris,  oculorum  et  narium  vasa  describuntur,  noviqve 
saliva:  lacrymarumque  et  muci  fontes  detegunlur  ct  novum  Bilsii  commentum  reji- 
cfur  Leyden,  1662.— Needham,  De  formatu  fœlu,  London,  1667;  in  the  preface.— 
G.  Blaes,  Mise.  an.  horn,  brutorumquc  fabricam  diversam  exhibentia,  Amsterdam, 

1 h74  * 


220 


DESCRIPTIVE  ANATOMY. 


from  without  inward  directly  under  the  skin  and  on  the  masseter  mus- 
cle. It  is  generally  from  three  to  five  lines  distant  from  the  lower  edge 
of  the  zygomatic  process.  The  transverse  facial  artery  and  some 
twigs  of  the  facial  nerve  accompany  it.  It  passes  on  the  anterior  edge 
of  the  masseter  muscle,  penetrates  between  the  fibres  of  the  buccinator 
muscle,  and  opens  in  the  lateral  walls  of  the  cavity  of  the  mouth 
opposite  the  first  posterior  molar  tooth  of  the  upper  jaw,  consequently 
before  the  range  of  the  teeth.  Its  orifice  is  single,  and  presents  a 
warty  prominence. 

We  not  unfrequently  find  an  accessory  parotid  gland  ( Gl . parotis 
acccssoria ),  situated  more  or  less  before  the  normal  parotid  gland,  on 
the  malar  bone  and  the  zygomatic  arch.  This  gland  never  communi- 
cates with  the  proper  parotid  gland,  and  sometimes  divides  into  two 
lobes  ; it  opens  by  a small  passage  into  the  parotid  candi.  It  may  be 
compared  with  the  orbitar  gland  of  several  mammalia. 


b.  Submaxillary  gland. 

§ 2095.  The  submaxillary  gland  (67.  maxillaris , s.  submaxillaris)(\ ) 
is  but  half  the  size  of  the  parotid  gland.  It  has  the  form  of  a rounded 
triangle.  It  is  thicker  below  than  above,  and  is  situated  on  a level 
with  the  angle  of  the  lower  jaw,  between  its  inner  face  and  the  body 
of  the  hyoid  bone. 

On  the  outside  it  touches  the  lower  part  of  the  inner  face  of  the 
pterygoideus  internus  muscle.  Forward  it  sends  a small  prolongation 
above  the  posterior  edge  and  the  posterior  part  of  the  lower  face  of  the 
rnylo-glossus  muscle.  It  rests  inward  on  the  posterior  extremity  of 
the  anterior  belly  of  the  digastricus  muscle,  posteriorly  on  the  stylo- 
glossus muscle. 

Although  this  gland  is  much  smaller  than  the  preceding,  it  is,  how- 
ever, composed  of  much  larger  lobes. 

The  excretory  duct,  called  the  canal  of  Wharton  ( ductus  Wharton- 
ianus),  arises  from  the  anterior  extremity  ; its  parietes  are  very  thin  in 
proportion  to  its  diameter,  and  it  is  larger  compared  with  the  size  of 
the  gland  than  the  duct  of  Steno.  Its  direction  is  obliquely  from 
without  inward  and  from  behind  forward  ; it  passes  above  the  rnylo- 
glossus  muscle,  below  and  on  the  inside  of  the  submaxillary  gland,  on 
the  outside  of  the  upper  edge  of  the  hyo-glossus  muscle,  and  terminates 
by  a small  verrucous  prominence  on  the  sides  of  the  frenum  of  the 
tongue,  consequently  behind  the  range  of  the  lower  teeth. 

Farther  inward  the  substance  of  the  gland  sends  off  a prolongation 
some  lines  thick,  which  follows  the  same  direction,  but  does  not  extend 
so  high,  passes  through  the  inner  part  of  the  posterior  extremity  of  the 


(1)  Wharton,  Adenographia,  ch.  xxi. — Van  Horne,  Dc  duclibus  salivalibus  disp. 

111. , 1656,  1658. 


OF  THE  DIGESTIVE  SYSTEM. 


221 


sublingual  gland,  and  opens  at  the  side  of  the  canal  of  Wharton,  some- 
times in  common  with  a small  excretory  duct  which  leaves  this  lat- 
ter gland.  This  common  duct  is  called  the  canal  of  Bartholini 
(ductus  Bartholinianus).(  1 ) 


c.  Sublingual  gland. 

§ 2096.  The  sublingual  gland  (Gl.  lingualis,  s.  sublingualis)(2)  is 
situated  before  the  preceding,  so  that  the  posterior  extremity  touches 
the  anterior  extremity  of  the  latter,  occupies  on  each  side  the  whole 
length  of  the  tongue,  and  may  be  found  directly  under  the  buccal  mem- 
brane, through  which  it  is  easily  felt,  and  is  even  visible,  on  account  of 
its  inequalities  and  prominences.  It  is  situated  between  this  mem- 
brane, the  myo-glossus,  the  genio-glossus,  the  genio-hyoideus,  and  the 
hyo-glossus  muscles.  It  is  formed  like  an  elongated  triangle,  and  it 
is  nearly  as  large  as  the  submaxillary  gland. 

It  is  composed  of  smaller  lobes  than  the  preceding,  is  whiter  and 
harder  than  it,  and  opens  not  like  the  two  glands  previously  described 
by  one  orifice,  but  by  several,  usually  seven  or  eight  ; it,  however, 
forms  no  distinct  excretory  duct.  We  perceive  these  openings  on  the 
lower  face  of  the  cavity  of  the  mouth  on  each  side  below  and  near  the 
tongue.  There  are  also  several  ducts  from  its  anterior  portion  ( ductus 
Riviniani ),  which  unite  with  that  of  the  submaxillary  gland  ; some- 
times one  only  anastomoses  with  a passage  formed  by  a division  of  this 
latter,  and  thus  give  rise  to  the  passage  of  Bartholini  (§  2095). 

§ 2097.  There  are  in  fact  no  other  salivary  glands  or  other  pas- 
sages which  carry  saliva.  Although  several  anatomists(3)  have  ad- 
mitted others,  it  has  long  been  proved  that  the  parts  considered  as 
such  are  simply  those  of  the  muciparous  glands  at  the  root  of  the 
tongue  or  around  the  larynx,  or  even  of  the  veins  of  the  back  of  the 
tongue. (4) 

§ 2098.  The  oral  glands  present  no  differences  in  respect  to  their 
development,  except  those  generally  remarked  in  all  glands. 


(1)  G.  Bartholini  has  discovered  it  in  the  lion  {De  duclu  salivali  hactenus  non 
descripto  observation  Leyden,  1684). 

(2)  A.  F.  Walther,  De  lingua  Humana  novis  inventis  octo  sublingualibus  salivœ 
viis , nunc  ex  suis  functionibus , glandulis  sublingualibus  eductis , Leipsic,  1724. 
— C.  J.  Trew,  De  tasis  linguae  salivalibus  atque  sanguiferis  epistola,  Nuremburg, 
1734. 

(3)  A.  Vater,  Novus  ductus  salivalis,  qui  in  linguæ  superficie  superior e circa  ejus 
medium  notdbili  orificio  hiat,  Wittemberg,  1720. — Id.,  Novus  ductus  salivalis  isque 
prœcipuus  in  lingua  excretorius  glandulœ  insignis  ad  latera  linguæ  et  sub  eadem 
sitce  itemque  super  radicem  linguæ , epiglottidem , circa  glottidem  super  arytœ- 
noideas  usque  intra  œsophagum  expansæ,  Wittemberg,  1721. — Id.,  De  ductu  salivali 
in  lingua  noviter  antehac  detecto,  nunc  dilucidato,  confirmato , novisque  experiments 
adducto,  una  ductus  excretorius  tonsillarum  ac  glandulæ  thyrcoideœ,  Wittemberg, 
1723. — G.  D.  Coschwitz,  De  ductu  salivali  novo , Halle,  1724. — Id.,  Continuatio  obser- 
vationum  de  ductu  salivali , Halle,  1729. 

(4)  Trew,  loc.  tit. 

VOL.  III. 


29 


222 


DESCRIPTIVE  ANATOM V 


B.  ABNORMAL  STATE. 

§ 2099.  The  anomalies  of  the  oral  glands,  generally  speaking,  pre- 
sent nothing  peculiar. 

Primitive  deviations  of  formation  are  very  rare. 

We  must,  however,  mention  as  such  the  abnormal  union  of  the 
parotid  and  submaxillary  glands. 

These  organs,  particularly  the  parotid  canal,  are  easily  wounded  ; 
this  causes  the  saliva  to  flow  outward,  and  thus  forms  salivary  fistula. 

The  closing  of  the  orifice  of  the  excretory  canal  of  the  submaxillary 
gland  is  often  at  least  the  cause  of  ranula , although  this  affection 
depends  very  frequently  on  a newly-formed  cyst.(l) 

Simple  enlargement  is  rare.  The  swelling  of  the  parotid  gland  in 
inflammation  is  situated  in  the  cellular  tissue  between  its  lobes. 

So  too  the  general  alterations  of  texture,  as  scirrhus  and  cancer, 
which  are  also  attended  with  an  increase  of  volume,  generally  occur 
not  in  the  glandular  tissue,  but  in  the  lymphatic  glands,  which  are 
situated  on  the  inside  and  below  the  salivary  glands,  since  the  glan- 
dular tissue  is  generally  unaffected  in  this  case. (2) 

The  tumors  developed  in  the  lower  jaw  are  also  situated  in  the 
lymphatic  glands  of  the  neck.  Sometimes  we  meet  here,  as  in  other 
parts  of  the  system,  accidental  ossifications  with  formations  entirely 
abnormal.  (3) 

Calculous  concretions  are  formed  in  the  amygdalae  and  the  salivary 
passages,  especially  in  the  excretory  ducts  of  the  submaxillary  gland. 
These  calculi  are  composed,  according  to  Fourcroy,(4)  of  an  animal 
matter  and  of  phosphate  of  lime.  If  however  we  may  judge  from 
external  characters,  a salivary  calculus  described  by  us(5)  seems  more 
similar  to  those  biliary  concretions  which  have  cholesterine  for  their 
base. 

The  calculi  developed  in  the  amygdalæ  are  of  a dirty  white  color. 
The  disagreeable  odor  which  they  generally  possess  probably  de- 
pends,(6)  at  least  in  great  part,  on  the  decomposition  of  animal 
matter  which  surrounds  them  and  enters  into  their  composition  ; for 
frequently  this  matter  alone  is  very  disagreeable,  and,  like  the  forma- 

(1)  Breschet,  Considérations  sur  la  tumeur  nommée  communément  ranulc  ou 
grenouillette  ; in  the  Journ.  univ.  dessc.  méd.,  vol.  viii.,  p.  296. 

(2)  Burns,  Anatomy  of  the  head  and  neck , p.  270. 

(3)  Burns,  loc.  cit.,  p.  283. 

(4)  Syst,  des  conn,  chim .,  vol.  ix.,  p.  312. — John  has  found  nothing-  else  in  two 
salivary  calculi,  one  of  which  come  from  th,e  tissue  of  the  parotid  gland  : Chemische 
Zerlegung  einer  Concretion  der  Parotis;  in  the  Deutsches  Arch,  für  die  Physio- 
logie. vol.  iv.,  p.  602  : Chemische  Zerlegung  einer  Speichelsteins  ; same  journal,  voL 
vi.,  p.  603. 

(51  Handhuch  der  pathologischen  Anatomie , vol.  ii.,  pt.  ii.,  p.  467. 

(6)  Burns,,  loc.  cit..  p.  265. 


OF  THE  DIGESTIVE  SYSTEM. 


223 


tion  of  the  calculi  of  which  we  are  speaking,(l)  depends  on  a derange- 
ment of  the  digestive  function. 


V.  TEETH. 

§ 2100.  The  teeth  (dentes)  { 2)  are  the  hardest  parts  of  the  body. 
In  their  chemical  and  physical  properties  they  resemble  the  bones,  but 
they  differ  from  them  in  their  mode  of  union  with  the  body,  in  their 
mode  of  development,  and  in  their  vital  phenomena.  In  all  these  res- 
pects they  are  more  similar  to  the  epidermoid  parts,  particularly  the 
nails  and  hairs. 


A.  NOBMAL  STATE. 

a.  Perfect  state. 

§ 2101.  1st.  Situation.  The  teeth  are  inserted  in  most  of  their  extent 
in  the  alveolar  processes  of  the  two  jaws,  which  closely  embrace  them, 
and  articulate  with  them  by  gomphosis.  The  portion  in  the  alveolar 
process  is  termed  the  roow*radix  dentis ).  The  rest  of  the  tooth,ls  not 
free.  The  centre,  which  is  the  smallest  part,  is  termed  ihe  neck 
( collum , s.  corona  dentis),  and  is  surrounded  by  the  gum  5 -all  the  por- 
tion above  projects,  and  is  exposed  in  the  cavity  of  the  mouth  ; this 
is  the  body  or  crown  of  the  tooth  (corpus,  s,  corona  dentis). 

(1)  Burns,  loc.  cit.,  p.  265. 

(2)  Treatises  on  the  teeth  generally  treat  of  their  anatomy,  physiology,  pathology, 
and  therapeutics,  and  differ  only  by  speaking  more  at  length  on  one  of  these  heads. 
We  mention  several  works  almost  entirely  pathological,  as  many  of  them  contain  a 
number  of  special  or  general  remarks  in  regard  to  their  anatomy  and  physiology  : 
Eustachius,  De  dentibus  libellus,  Venice,  1563. — B.  Martin,  Dissertation  sur  les 
dents,  Paris,  1679.— A.  C.  G.  Cumme,  Diss.  sist.  dentium  historiam,  Helmstadt, 
1715. — P.  Fauchard,  Le  chirurgien  dentiste,  ou  traité  des  dents,  Paris,  1728. — Le- 
cluse,  Nouveaux  élémens  d'odontologie,  Paris,  1754. — Bourdet,  Recherches  et  obser- 
vations sur  toutes  les  parties  de  l'art  du  dentiste,  Paris,  1757. — Curtis,  A treatise  on 
the  structure  and  formation  of  the  teeth,  Oxford,  1769. — F.  X.  de  Wasserberg, 
Aphorismi  anatomico-physiologici  de  dentibus,  Vienna,  1770.— J.  Hunter,  Natural 
history  of  the  human  teeth,  London,  1778. — H.  G.  Courtois,  Le  dentiste  observateur, 
Paris,  1775. — Broussonet,  Considérations  sur  les  dents  en  général  et  sur  les  organes 
qui  en  tiennent  lieu  ; in  the  Mém.  de  l’ac.  des  sc.,  1787,  p.  550. — A.  G.  Berger,  Diss. 
de  dentibus,  Kiel,  1788. — S.  H.  Bring,  Observationes  in  hodiernam  de  dentibus, 
præcipue  hominum,  doctrinam,  Lund,  1793. — F.  Hirsch,  Praktische  Bemerkungen 
über  die  Zahne,  Jena,  1801. — R.  Blake,  Essay  on  the  structure  and  formation  of  the 
teeth  in  man  and  various  animals,  Dublin,  1801. — J.  Fox,  Hist.  nat.  et  maladies  des 
dents  de  l’esp.  humaine,  Paris,  1821. — A.  Serres,  Essai  sur  l’ anatomie  et  la  phsio- 
logie  des  dents,  ou  nouvelle  théorie  de  la  dentition,  Paris,  1817. — F.  Lavagna,  Espe- 
rienze  e riflessioni  sopra  la  carie  dei  denti,  Genes,  1821. — Heilbronn,  Diss.  de  denti- 
bus, Berlin,  1821. — C.  G.  Kaathover,  De  dentium  formatione  atque  natura,  Leyden, 
1821. — J.  Lemaire,  Traité  sur  les  dents,  Paris,  1822. 


224  DESCRIPTIVE  ANATOMY. 

The  root  and  neck  of  the  teeth  are  covered  with  a thin  membrane  ; 
this  is  continuous  below  with  a nervous  and  vascular  tissue  which 
fills  the  cavity  of  the  tooth,  and  above  with  the  gum  ; it  is  termed  the 
dentar  periosteum , although  the  history  of  dentition  seems  to  demon- 
strate that  its  relations  with  the  teeth  are  not  the  same  as  those  be- 
tween the  periosteum  and  the  bones. 

The  alveolar  processes  are  also  covered  by  a fibrous  and  thick  mem- 
brane, which  in  the  normal  state  does  not  unite  with  the  preceding, 
but  is  continuous  with  the  upper  part  of  the  gum,  and  is  termed  the 
alveolar  periosteum. 

The  gums  ( gengivœ ) are  a firm,  resisting  cellular  tissue  about  half 
a line  thick,  which  adhere  intimately  with  the  buccal  membrane,  and 
receive  but  few  vessels  or  nerves.  They  cover  the  neck  of  the  teeth, 
and  also  the  two  faces  of  the  alveolar  edges  of  the  jaws,  and  furnish 
thin  prolongations  which  extend  between  each  two  teeth,  from  the 
anterior  to  the  posterior  face. 

The  teeth  of  each  jaw  collectively  form  an  arch  which  is  concave 
backward  and  convex  forward. 

They  are  generally  arranged  very  compactly,  and  are  placed  at 
equal  distances  from  each  other.  The  upper  and  the  lower  touch  at 
their  summits.  The  arch  formed  by  the  upper  teeth  is  a little  longer 
than  the  other.  Hence  the  upper  teeth  slieîtly  project  outward,  and 
the  anterior,  which  are  thinner,  cover  the  otimrs.  The  posterior  and 
inferior  t#eth  have  their  summits  slightly  inclined  inward,  while  those 
of  the  uppesare  turned  more  directly  downward. 

2d.  Form.  All  the  teeth  are  more  or  less  elongated  ; their  lower 
extremity  is  slightly  pointed,  and  there  presents  a small  opening  which 
leads  into  the  cavity  of  the  tooth  ( cavum  dentis).  This  cavity  extends 
from  the  summit  of  the  roots  to  the  crown,  and  is  very  narrow  in  pro- 
portion to  its  length,  represents  the  form  of  the  tooth,  and  lodges  its 
vessels  and  nerves,  which  are  connecte  I by  cellular  substance. 

3d.  JYumber.  The  number  of  the  teeth  is  the  same  in  the  two  jaws, 
on  the  two  sides,  and  in  the  two  sexes.  In  a well  developed  man 
there  are  thirty-two. 

4th.  Texture.  The  tissue  of  the  teeth  is  very  hard  and  solid.  They 
are  composed  of  two  substances,  the  osseous  substance  and  the  enamel. 

§ 2102.  The  osseous  substance  or  the  ivory  forms  the  largest  part  of 
the  tooth,  the  root,  the  neck,  and  almost  all  the  crown.  It  conse- 
quently represents  the  form  of  the  whole  tooth.  Its  hardness,  which 
exceeds  that  of  the  bones,  depends  upon  its  mechanical  arrangement 
and  on  its  chemical  composition.  In  fact  it  contains  no  cellules. 
We  perceive  in  it  but  not  very  clearly  only  longitudinal  layers, 
situated  one  upon  another  from  without  inward,  and  it  contains 
more  of  lime  than  the  other  bones.  Berzelius  asserts(l)  that  one 


(1)  Gehlen,  Journ.  fur  die  Chimie  und  Phys.,  vol.  iii.,  part  i.,  p.  19. 


OF  THE  DIGESTIVE  SYSTEM. 


225 


hundred  parts  of  this  substance  contain  51.04  of  phosphate  of  lime  ; 
2.00  of  fluate  of  lime  ; 11.30  of  carbonate  of  lime  ; 1.16  of  phosphate 
of  magnesia  ; 1.20  of  soda  ; and  an  indeterminate  quantity  of  hydro- 
chlorate of  soda.  Pepys  states  that  they  contain  0.64  of  phosphate  of 
lime;  0.6  of  the  carbonate;  0.20  of  gelatine;  and  0.10  of  water,  in- 
cluhng  the  loss.(l) 

I 2103.  The  enamel  {substantia  vitrea)  (2)  is  milk  white,  brilliant, 
semitransparent,  and  still  harder  and  firmer  than  the  osseous  substance. 
It  covers  all  the  crown  of  the  tooth,  is  molded  exactly  upon  it,  and 
preserves  all  the  inequalities  of  its  masticating  surface,  where  it  is 
thickest.  It  gradually  grows  thinner  towards  the  neck.  It  is  com- 
posed of  oblique,  undulating,  serrated  bands,  concave  upward,  convex 
downward,  which  are  arranged  compactly  from  above'  downward,  and 
exactly  fit  to  each  other.(3) 

The  enamel  contains  still  more  of  earthy  salts  than  the  osseous  sub- 
stance. We  find  in  it,  according  to  Morichini  :(4)  0.33  of  lime  ; 0.09 
of  magnesia  ; 0.05  of  alumina  ; 0.22  of  fluoric  and  phosphoric  acids  ; 
Ö.01  of  carbonic  acid  ; and  0.30  of  animal  substance. 

According  to  Hatchett(5)  it  contains  very  little  of  gelatine,  and  is 
mostly  formed  of  phosphate  of  lime. 

Foucroy  and  Yauquelin(6)  state  that  it  is  composed  of  72.90  of 
phosphate  of  lime,  and  27.10  of  gelatine  and  water. 

Pepys  asserts(7)  that  it  is  formed  of  0.78  of  phosphate  of  lime  ; 0.60 
of  the  carbonate  ; and  0.16  of  water. 

Finally,  Berzelius(8)  mentions  as  its  component  parts  : 85.3  of  the 
phosphate  ; 3.3  of  the  fluate  ; 8.0  of  the  carbonate  of  lime  ; 1.5  of  the 
phosphate  of  magnesia  ; and  2.0  of  animal  substance  and  water. 

§ 2104.  The  vessels  and  nerves  of  the  teeth  are  proportionally  very 
large.  The  first  arise  from  the  internal  maxillary  artery  ; the  nerves 
come  from  the  second  and  third  branch  of  the  trifacial  nerve,  penetrate 
through  the  openings  at  the  summit  of  the  roots,  correspond  perfectly 
to  them  in  number,  descends  into  the  cavity  of  v the  tooth,  where, 
united  by  cellular  tissue,  they  form  the  nucleus  or  pulp  of  the  tooth 
( pulpa , s.  nucleus).  These  nerves  enlarge  near  the  neck  of  the  tooth, 


(1)  Fox,  loc.  cit. 

(2)  Ludwig-,  De  cortice  dentium,  Leipsic,  1753. — Schreg-er,  Uber  den  Zahn- 
schmelz ; in  Rosenmullcr  and  Isenflamm,  Beiträge  zur  Zergliederungskunst,  vol. 
i.,  part  i. 

(3)  Cumme,  loc.  cit.,  p.  9. — Schreger,  loc.  cit. 

(4)  Analisi  delta  smalto  di  un  dente  di  elefante  c dei  denti  umani  ; in  the  Memoire 
della  societa  italiana,  vol.  x.,  pt.  i.,  p.  162  ; vol.  xii.,  pt.  ii.,  p.  73. 

(5)  Phil,  trans.,  1799. 

(6)  Mém.  de  V Institut.,  vol.  ii.,  p.  283. — Annales  de  chim.,  vol.  lv.,  p.  265  ; vol. 
lvii.,  p.  37. 

(7)  Loc.  cit. 

(8)  Gehlen,  Journ.für  phys.  und  Chem.,  vol.  iii.,  part  i.,  p.  27. 


226 


DESCRIPTIVE  ANATOMY. 


become  soft  and  reddish,  and  seem  covered  with  a network  of  ves- 
sels.^) 

§ 2.105.  These  characters  are  common  to  all  the  teeth  ; but  there  are 
others  in  respect  to  which  they  differ,  and  hence  they  may  b^divided 
into  several  classes. 

They  differ  from  each  other  in  several  respects,  but  principally  in 
regard  to  : \ 

1st.  Their  situation. 

2d.  Their  form. 

3d.  Their  duration. 

4th.  The  period  of  life  at  which  they  appear. 

§ 2106.  In  respect  to  situation , the  most  general  difference  is  that 
which  exists  between  the  teeth  of  the  upper  and  those  of  the  lower 
jaw.  The  latter  differ  from  the  former  in  being  a little  smaller,  so  that 
the  curve  represented  by  their  union  is  narrower  and  shorter  ; hence 
the  upper  row  of  teeth  projects  a little  beyond  the  lower  in  every  part. 

§ 2107.  The  teeth  sj(  the  same  jaw  differ  from  each  other  in  form  ; 
hence  their  division  into  three  classes,  the  incisors , the  canine , and  the 
molar  teeth. 

§ 21  OS.  The  incisors  ( dentes  incisivi , incisores,  primores ) are  eight 
in  number,  four  in  each  jaw,  occupying  the  most  internal  and  the  most 
anterior  part.  They  differ  most  from  the  others  in  the  form  of  their 
crown.  The  latter  is  chisel-shaped,  and  becomes  much  thinner  from 
the  neck  to  the  summit,  which  presents  the  cutting  surface.  The 
posterior  face  is  vely  concave  and  the  anterior  is  convex,  but  not  in 
the  same  proportion.  The  incisors  begin  to  become  extremely  thin 
from  their  centres.  In  the  perfect  state,  when  they  have  not  been  used 
for  mastication,  their  edge  is  divided  into  a middle  and  two  lateral 
small  grooves  ; but  these  grooves  soon  disappear,  and  the  summit  of 
the  tooth  then  forms  only  a- thin  straight  line,  which  extends  the  whole 
breadth' of  the  crowp.  , 

These  teeth  have  but  one  root.  It  diminishes  imperceptibly  from 
the  crown  to  its  extremity.  A depression  not  unfrequently  exists  its 
whole  length  on  each  side,  indicating  the  division  of  this  root  into  two 
halves,  an  anterior  and  a posterior  ; and  even  the  summit  is  divided 
into  two  small  grooves,  an  anterior  and  a posterior. 

The  incisors  differ  from  the  other  teeth  in  their  direction  ; they  are 
situated  more  transversely,  so  that  their  loose  face  looks  forward  ; the 
other  is  turned  backward,  and  their  cutting  edge  extends  from  one  side 
to  the  other. 

§2109.  The  incisors  also  differ  much  from  each  other.  The  dif- 
ference between  the  synonjnnous  teeth  of  the  two  jaws  is  no  where  so 
striking  as  in  them,  even  when  they  are  most  similar  in  size.  Those 
of  the  upper  jaw,  however,  extend  half  a tooth  farther  outward  than 


(1)  Serres,  loc,  cit.,  p.52. 


OF  THE  DIGESTIVE  SYSTEM. 


227 


those  of  the  lower  jaw.  The  superior  are  twice  as  large  as  the  in- 
ferior. 

The  incisors  of  the  lower  jaw  differ  also  from  the  others  both  in  size 
and  for«.  In  fact  they  all  have  a chisel-like  form,  and  their  external 
edge  is  about  as  high  as  their  internal.  Sometimes,  even,  they  are 
all  similar  in  this  respect.  But  most  commonly  their  external  edge 
descends  a little  lower  than  the  internal,  and  is  continuous  with  the 
other  by  a rounded  angle. 

The  internal  inferior  incisors  possess  this  form  very  seldom,  and  the 
others  very  generally.  In  the  external  superior  incisqjs  the  internal 
edge  is  a little  convex  outwardly,  and  is  insensibly  continuous  with  the 
lower,  although  a little  farther  downward,  so  that  the  cutting  surface 
is  narrower  than  the  greatest  breadth  of  the  tooth. 

These  differences  in  form  deserve  notice,  as  they  establish  the  gra- 
dual transition  from  the  internal  inferior  incisors  to  the  canine  teeth 
through  the  medium  of  the  others. 

In  respect  to  the  size,  the  inner  pair  of  incisors  in  the  upper  jaw  are 
a little  and  ofteir  much  larger  than  the  outer  ; while  in  the  lower  jaw 
the  incisors  are  about  the  same  size,  or  the  outer  pair  is  a little  larger 
than  the  inner. 

§ 2110.  Next  to  the  incisors  come  the  four  canine  teeth  ( dentes 
canini , ferini,  cuspidati ),  one  on  each  side.  Their  crown  is  much 
thicker  from  before  backward  than  that  of  the  incisors,  but  it  does  not 
diminish  as  rapidly  from  above  downward  ; hence  why  their  summits 
are  less  cutting.  This  summit  is  also  pointed,  because  the  lower  face 
does  not  describe  a straight  line,  as  the  two  lateral  faces  terminate 
higher  than  in  the  incisors,  and  as  the  crown  of  the  canine  teeth  is  as 
elevated  as  that  of  the  latter,  it  follows  that  the  lower  face  is  composed 
of*two  parts  which  unite  in  the  centre  at  an  acute  angle,  Conse- 
quently the  crown  is  more  rounded  and  more  conical  ; it  extends  both 
inward  and  outward  above  that  of  the  incisors.  On  the  posterior  face 
we  perceive  from  ab^ve  downward  in  the  centre  a slight  prominence, 
between  which  and  the  edges  there  is  a small  depression.  This  ar- 
rangement is  more  evident  in  the  inferior  than  in  the  superior  canine 
teeth. 

Of  all  the  teeth  the  canine  have  the  longest  roots.  These  roots  are 
single  and  pointed.  We  generally  observe  in  them  the  groove  men- 
tioned when  speaking  of  the  external  incisors. 

§ 2111.  In  the  posterior  part  of  the  jaw  are  the  twenty  molar  teeth 
(dentes  molares),  ten  in  each  jaw,  five  on  each  sid^  They  are  similar 
to  each  other,  and  differ  from  the  other  teeth  : 

1st.  In  the  greater  breadth  of  their  triturating  surface,  which  de- 
pends on  the  fact  that  the  posterior  face  of  the  crown  does  not  descend 
obliquely  to  meet  the  anterior,  but  is  parallel  with  it. 

2d.  In  the  square  or  rounded  form  of  this  surface  generally. 

3d.  In  the  considerable  elevations  and  depressions  in  this  triturating 
surface. 


228 


DESCRIPTIVE  ANATOMY. 


4th.  In  the  lowness  of  their  crown. 

5th.  In  the  division  of  their  roots  into  several  distinct  branches,  or 
at  least  they  are  much  more  distinct  than  any  other  teeth  where  this 
division  is  only  indicated. 

§ 2112.  Notwithstanding  this  general  similarity  they  differ  very 
much’  particularly  the  two  anterior  and  the  three  posterior.  The  first 
are  .termed  the  small  molar  or  bicuspid  teeth  ( molares  anteriores , s. 
minores , s.  bicuspidati) , and  the  others,  which  are  larger,  the  great 
molar  or  multicuspid  ( molares  posteriores,  s.  majores,  s.  multicuspi- 
dali). 

§ 2113.  mie  small  molar  teeth  differ  from  the  great  : 

1st.  By  their  smallness.  They  are  at  least  one  half  smaller. 

2d.  By  their  compression  from  one  side  to  the  other. 

3d.  By  their  triturating  surface,  which  is  less  uneven. 

4th.  By  the  form  of  their  roots.  The  latter  are  at  most  bicuspid, 
and  even  when  they  assume  this  form  they  are  so  only  in  the  part 
farthest  from  their  crown,  that  is,  they  never  present  as  deep  a fissure 
as  the  posterior  molar  teeth.  In  most  cases  they  are  broader  from 
within  outward  than  those  of  the  incisors  and  the  canine  teeth,  are 
terminated  by  a blunter  summit,  and  their  lateral  grooves  are  more 
superficial. 

The  triturating  surface  of  the  small  molar  teeth  generally  presents 
two  eminences,  one  anterior  and  external,  the  other  posterior  and  in- 
ternal. From  this  they  take  their  name.  This  arrangement  is  more 
evident  in  the  upper  jaw,  because  the  two  eminences  are  there  sepa- 
rated by  a deep  transverse  groove.  In  the  lower  jaw  the  eminences 
of  the  small  molar  teeth  are,  on  the  contrary,  united  by  a crest,  the 
direction  of  which  is  from  without  inward.  This  difference  deserves 
notice,  because  the  canine  teeth  of  the  two  jaws  (§  2110)  differ  from 
each  other  in  the.  same  manner.  The  external  anterior  eminence  is 
always  higher  than  the  internal,  particularly  in  the  first  small  inferior 
molar  tooth,  where  the  internal  is  but  slightly  developed,  and  which,  in 
these  two  respects,  evidently  makes  the  transition  from  the  canine  to 
the  other  molar  teeth. 

But  this  is  not  true  of  the  second  small  anterior  molar  tooth.  In 
this  we  usually  observe,  behind  the  posterior  eminence,  a smaller  and 
more  prominent  tubercle,  or  sometimes  the  posterior  eminence  is  di- 
vided into  two  equal  halves.  At  the  same  time  the  external  is  lower, 
the  crown  and  the  triturating  surface  are  still  more  rounded,  so  that 
this  tooth  evidenth^tnakes  the  transition  from  the  anterior  to  the  pos- 
terior molar  teeth  ; it  is  also  a little  larger  than  the  internal. 

The  small  superior  molar  teeth  are  more  similar  to  the  large  than 
the  inferior  are,  on  account  of  the  greater  development  of  their  posterior 
tubercle. 

§ 2114.  The  three  posterior  molar  teeth  generally  present  four  blunt 
tubercles,  two  on  the  outside,  and  two- on  the  inside,  which  are  sepa- 
rated by  a crucial  depression.  But  we  usually  observe  also  between 
the  posterior  two,  on  the  edge  of  the  triturating  surface,  a fifth,  which 


OF  THE  DIGESTIVE'  SYSTEM. 


229 


Is  smaller.  These  tubercles  are  also  rough.  The  external  prominences 
are  generally  the  largest  and  most  numerous,  and  frequently  the  in- 
ternal tubercle  is  single,  especially  in  the  last  two  molar  teeth.  The 
last  great  molar  tooth  is  usually  the  smallest,  and  the  first  the  largest. 

Most  generally  the  roots  of  these  molar  teeth  present  three  branches, 
into  which  they  frequently  divide  near  their  crown.  The  last,  it  is 
true,  generally  has  but  one  root,  but  this  root  is  never  as  pointed  as  hi 
the  canine  teeth  and  the  incisors,  and  it  always  presents  at  least  two 
very  deep  and  very  broad  grooves,  which  indicate  a tendency  to  divide. 
Sometimes  also  the  other  two  great  molar  teeth  have  only  two  branches 
at  their  root  ; but  in  this  case  one  of  the  branches  is  always  much 
broader  than  the  other,  and  also  presents  a broad  and  deep  groove.  In 
some  subjects  this  broad  unmated  branch  bifurcates  below  into  two 
small  points.  The  branches  of  the  roots  of  the  molar  teeth  are  usually 
more  curved  than  the  simple  roots  of  the  incisors  and  canine  teeth  ; 
they  begin  by  separating  from  each  other  ; they  then  converge  more 
or  less  at  their  lower  extremity,  where  they  even  touch  each  other, 
and  blend  together  at  their  summits,  so  that  they  intercept  between 
them  a portion  of  the  upper  maxillary  bone. 

§ 2115.  The  characters  which  we  have  mentioned  are  those  by 
which  we  distinguish  the  teeth  which  remain  in  the  jaws  during  most 
of  fife.  But  there  are  other  different  teeth  which  exist  but  a short  time, 
in  youth,  and  are  termed  the  deciduous , or  milk  teeth  ( dentes  clecidui,  s. 
infantiles , s.  lac  lei),  in  opposition  to  the  first,  which  are  termed  the  per- 
manent teeth  {dentes  permanentes). 

The  teeth  which  appear  at  first  do  not  continue  during  life  ; many 
of  them  remain  only  till  the  seventh  year,  and  at  the  fourteenth  year 
all  are  replaced  by  new  permanent  corresponding  teeth. 

§ 2116.  The  two  classes  of  teeth  differ  from  each  other  in  number 
and  form. 

In  the  first  respect,  we  ought  not  to  find  more  than  two  molar  teeth 
in  each  half  of  the  jaw,  during  the  period  of  the  deciduous  teeth,  whence 
there  are  only  twenty  deciduous  teeth,  while  there  are  thirty-two  per- 
manent teeth. 

In  respect  to  form,  we  distinguish  also  among  the  deciduous  teeth, 
the  incisors,  the  canine,  and  the  molar  teeth.  The  incisors  and  the 
canine  teeth  resemble  the  permanent  teeth  in  form,  number,  and 
situation  ; but  all  the  deciduous  teeth,  and  particularly  the  molar 
teeth,  differ  from  their  corresponding  permanent  teeth. 

1st.  Their  crown  is  much  stronger  in  proportion  to  their  root. 

2d.  They  are  less  elevated. 

All  do  not  present  the  same  peculiarities  in  respect  to  size.  The 
deciduous  incisors  and  canine  teeth  are  much  smaller  than  the  perma- 
nent teeth,  particularly  in  the  lower  jaw.  The  contrary  occurs  in  the 
molar  teeth  ; they  come  immediately  after  the  canine  teeth,  the  two 
small  anterior  molar  teeth  replace  them,  and  the  three  molar  teeth 
behind  them  are  permanent.  Hence  the  small  anterior  molar  teeth 
among  the  permanent  teeth  are  those  which  correspond  to  the  decidu- 

Vol.  III.  30 


230 


DESCRIPTIVE  ANATOMY. 


ous  molar  teeth  at  least  in  respect  to  situation.  But  the  latter  are 
much  larger  ; they  have  not  the  same  form  as  the  small  permanent 
molar  teeth,  for  instead  of  being  flattened  from  before  backward,  they 
are  extremely  broad,  have  a broad  square  crown,  and  also  several, 
usually  five  tubercles,  which  are  arranged  around  a very  deep  median 
groove.  The  anterior  is  nearly  one  half  smaller  than  the  posterior, 
although  the  posterior  is  almost  as  large  as  the  largest  of  the  perma- 
nent teeth.  Besides,  they  have  always  at  least  two  and  usually  three 
roots.  Thus  they  correspond  to  the  permanent  small  molar  teeth  only 
in  number  and  situation,  for  in  respect  to  size  and  form,  that  is,  in  two 
respects  much  more  important  than  the  two  preceding,  they  are  analo- 
gous to  the  three  permanent  great  molar  teeth. 

b.  Differences  depending  on  development. (I) 
a.  General  remarks. 


§ 2117.  The  teeth  pass  through  several  periods,  during  which  per- 
haps they  differ  more  than  any  other  part  of  the  body. 

The  history  of  their  development  presents  several  very  curious  phe- 
nomena. The  most  essential  points  to  consider,  are  their  mode  of 
development,  the  period  at  which  they  appear,  and  their  changes 
during  life. 

1st.  The  teeth  are  developed  in  small  rounded  and  close  sacs,  which, 
adhere  very  closely  to  the  gums.  These  sacs  are  composed  of  two 
membranes.  Hunter  thinks  that  the  internal  alone  is  vascular,  while 
Black  admits  this  only  of  the  external.  But  we  have  ascertained 

(1)  Besides  the  works  mentioned  previously,  which  also  treat  on  this  subject,  we 
may  consult  the  following  : J.  J.  Rau,  De  ortu  et  generatione  dentium,  Leyden,  1694. 
— J.  A.  Ungebauer,  De  dcntitione  secundâ  ; in  Haller,  Coll,  diss.,  vol.  vi.— J.  G.  Jancke, 
De  ossibus  mandibularum  puerorum  septennium,  Leipsic,  1751. — B.  S.  Albinus,  Ds 
dentium  ortu  ét  incremento  ; in  Annot.  acad..  vol.  ii.  eh.  ii.,  Quot  dentes  mutet  puer, 
et  quos,  ibid.,  ch.  iii.,  De  dentium  mutatione,  ibid.,  ch.  i. — Jourdain,  Essai  sur  la 
formation  des  dentes  comparée  avec  celle  des  os,  suivi  de  plusieurs  expériences  sur  les 
os  et  sur  les  parties  qui  entrent  dans  leur  composition,  Paris,  1766. — A.  A.  Brunner, 
De  eruptione  dentium  lacteorum  ; in  Wasserberg,  Opp.  min.,fasc.  I,  Francfort,  1775. 
— M.  Girardi,  De  re  anatomicâ  oratio,  Parma,  1781,  tab.  i. — Andree,  De  prima  pue- 
rorum dentitione,  Leipsic,  1790. — Léveillé,  Mémoire  sur  les  rapports  qui  existent 
entre  les  premières  et  les  secondes  dents,  et  sur  la  disposition  favorable  de  ces  der- 
nières au  développement  des  deux  mâchoires  ; in  the  Mém.  de  la  soc.  méd.  d’Emul., 
voL  viii.,  Paris,  1811. — Mie),  Quelques  idées  sur  le  rapport  des  deux  dentitions  et  sur 
V accroissement  de  la  mâchoire  dans  l’homme  ; same  journal. — Duval,  Mémoire  sur 
la  position  relative  de  l’ouverture  externe  du  canal  maxillaire,  pour  servir  à la  dé- 
monstration de  l’accroissement  delà  mâchoire  inférieure,  Paris,  1812. — J.  F.  Meckel, 
Essai  sur  le  développement  des  dents  chez  l’homme  ; in  the  Journ.  compl.  des  sc.  méd., 
vol.  i.  p.  365. — Miel,  Note  sur  la  manière,  dont  les  dents  sortent  des  alvéoles  et  traver- 
sent les  gencives  ; in  the  Journ.  de  méd.,  vol.  xxxix.  p.  235. — J.  E.  Oudct,  Observa- 
tion d’une  altération  de  la  racine  d’une  dent  canine,  présentant  les  caractères  exté- 
rieurs de  la  maladie  des  os,  connue  sous  le  nom  de  spinu  veniosa,  précédée  de  quelques 
considérations  générales  sur  la  phys.  dentaire  ; in  the  Archiv,  gén.  de  méd.,  vol.  i., 
p.  340. — Geoffroy  Saint  Hilaire,  Système  dentaire  des  mammifères  et  des  oiseaux, 
embrassant  sous  de  nouveaux  rapports  les  principaux  faits  de  l'organisation  den- 
taires chez  l'homme , Paris,  1824. 


OF  THE  DIGESTIVE  SYSTEM. 


231 


from  examining  the  human  fetus,  and  those  of  animals,  and  Fox  has 
also  determined  that  these  two  membranes  receive  vessels  ; the  blood, 
however,  seems  to  flow  more  abundantly  to  the  external  than  to  the 
internal.  A serous  fluid  exists  between  these  two  layers,  and  the  dis- 
tance between  them  is  much  greater  the  younger  the  fetus  is,  although 
the  layers  themselves  are  more  difficult  to  demonstrate  than  in  fetuses 
of  a certain  age,  on  account  of  their  extreme  smallness. 

The  external  layer  is  more  spungy,  looser,  thicker,  and  softer, 
than  the  internal.  It  is  very  distinctly  continuous  with  the  gum, 
whence  it  is  easy,  in  the  fetus,  especially  during  the  early  months  of 
pregnancy,  to  extract  the  alveoli  attached  to  the  gum. 

The  internal  layer  is  harder,  but  thinner  than  the  external.  We  can 
demonstrate  that  it  forms  a sac  entirely  distinct  from  the  external  and 
from  the  gum.  Its  relations  with  the  teeth  are  more  intimate  than 
those  of  the  external  layer,  for  it  is  the  proper  organ  of  formation. 
The  vessels  of  the  teeth  are  distributed  there  much  more  evidently, 
and  when  injections  succeed,  it  appears  entirely  red. 

2d.  The  small  sacs  or  follicles  appear  very  early.  About  the  tenth 
week  we  observe  very  distinctly  in  each  half  of  the  two  jaws,  four,  two 
anterior  which  are  smaller,  and  two  posterior  which  are  larger  ; they 
are  arranged  very  compactly  in  pairs,  but  the  anterior  and  the  pos- 
terior are  separated  by  a considerable  space.  At  the  end  of  the  third 
month  we  find  a third  sac  between  the  two  pairs,  and  thus  at  this 
period  the  whole  number  of  follicles  is  twenty.  We  generally  discover 
-at  the  end  of  the  fourth  month,  a sixth,  situated  entirely  backward, 
and  which  is  destined  for  the  most  anterior  permanent  molar  teeth. 

3d.  At  first  these  small  sacs  contain  only  a reddish  fluid,  which 
afterwards  becomes  yellowish  white.  After  a certain  time,  at  the 
fourth  month  of  pregnancy,  a small  reddish  and  soft  body  rises  from 
the  base  of  the  internal  membrane  ; this  gradually  becomes  more  con- 
sistent, and  forms  the  germ  or  pulp  of  the  tooth  (pulpits  dentis).  Nu- 
merous vessels  and  nerves  given  off  from  the  base  of  the  inner  mem- 
brane, are  distributed  in  this  small  body,  which  seems  to  be  enveloped 
by  a vascular  membrane,  which  is  difficult  to  be  detached  from  its  own 
proper  substance.  It  is  at  first  very  low,  is  single  in  every  part,  and 
terminated  by  a rounded  summit;  but  it  soon  assumes  the  peculiar 
form  of  each  kind  of  tooth,  and  presents  its  exact  image,  and  is,  in  fact, 
the  nucleus  around  which  the  tooth  is  molded.  The  latter  is  so 
developed  that  the  loose  portion  appears  first,  and  presents  all  the  de- 
pressions and  the  eminences  which  exist  upon  it,  while  the  rest  is  not 
yet  formed. 

The  teeth  begin  to  ossify  about  the  middle  of  pregnancy.  On  the 
loose  face  of  the  germ  very  delicate,  thin,  and  elastic  small  points  first 
appear  ; these  are  primitively  soft,  but  gradually  become  thicker  and 
more  consistent.  These  points  are  grooved  and  very  slightly  elevated. 
They  are  seen  first  on  the  most  prominent  part  of  the  germ,  and  repre- 
sent the  tubercles  of  the  future  tooth.  One  is  developed  on  each 
prominence  of  the  pulp  of  the  tooth  ; they  gradually  unite  with  each 


232 


DESCRIPTIVE  ANATOMY, 


other  ; they  begin  to  develop  themselves  only  when  a portion  of  the 
region  of  the  germ  corresponding  to  the  crown  is  formed,  and  embrace, 
that  part  of  the  pulp,  which  they  covër  so  closely,  that  some  exertion 
is  necessary  to  separate  them.  Their  internal  face  and  the  external 
face  of  the  germ  are,  however,  perfectly  smooth.  The  difficulty  in 
separating  them  depends  only  on  the  exact  manner  in  which  they  are 
fitted  to  the  latter,  since  by  removing  one  scale,  we  can  extract  the 
whole  germ  through  the  space  thus  formed.  Hence,  it  is  very  probable 
that  there  is  no  organic  attachment  between  the  pulp  and  the  osseous 
substance,  so  that  these  two  parts  of  the  tooth  are  united  by  vessels, 
by  cellular  tissue,  or  by  some  other  analogous  substance.  But  it  is 
very  curious  that  the  germ  is  redder  in  the  parts  covered  by  the  osseous 
substance,  and  that  the  progress  of  this  redness  is  in  direct  ratio  with 
that  of  ossification. 

The  points  soon  enlarge,  so  that  they  are  much  thicker  in  the  parts 
first  developed,  that  is,  on  the  triturating  surface.  They  become  much 
thinner  posteriorly,  where  they  are  much  softer.  The  crown  gradu- 
ally enlarges,  and  its  development  is  finally  completed.  Its  lower  ex- 
tremity contracts  and  becomes  the  neck  of  the  tooth.  The  roots  are 
prolongations  of  the  crown,  in  forming  which  the  germ  follows  pre- 
cisely the  same  course  as  in  giving  rise  to  the  latter.  The  number  of 
the  roots,  even  when  the  germ  has  formed  only  the  crown  of  the  tooth, 
is  indicated  by  that  of  the  distinct  branches  given  off  by  its  vessels. 

The  osseous  substance  forms  from  without  inward,  so  that  the  small 
tubercles  which  first  appear  are  also  the  parts  which  always  remain 
exposed,  and  the  triturating  surface,  like  the  existing  portion  of  the 
tooth,  has  already  its  normal  volume,  while  it  is  still  very  thin,  and  its 
internal  cavity  is  very  large.  This  phenomenon  demonstrates,  un- 
doubtedly, that  the  bony  portion  of  the  tooth  is  not  formed  by  the  inner 
face  of  the  capsule,  but  by  the  external  face  of  the  germ,  since  if  this 
were  not  true,  the  opposite  arrangement  would  exist.  This  osseous 
portion  gradually  thickens,  and  the  pulp  and  the  dental  cavity  diminish 
in  the  same  ratio,  although  we  cannot  suppose  that  the  germ  ossifies. 

Shortly  after  the  development  of  the  osseous  points,  or  during  their 
formation,  the  secretion  of  the  enamel  commences,  by  the  inner  face  of 
the  inner  fold  which  surrounds  the  crown  of  the  tooth,  so  as  to  be  per- 
fectly molded  upon  its  prominences  and  depressions.  The  fluid  ex- 
haled by  this  membrane  deposits  the  enamel  on  the  osseous  substance, 
which  is  so  soft,  and  adheres  so  slightly  to  this  latter  in  the  full  grown 
fetus,  that  they  maybe  very  easily  separated.  It  can  be  detached 
also,  even  in  the  perfect  state,  from  the  influence  of  certain  causes, 
among  others,  by  the  action  of  heat.  We  discover  no  special  gland 
for  its  secretion.  It  may,  however,  be  easily  separated  from  the  pro- 
longations of  the  internal  layer.  These  prolongations  which  arise 
from  the  portion  of  the  capsule  attached  to  the  germ,  are  at  first  very 
thick  and  moist  ; they  gradually  disappear  as  the  enamel  forms,  so 
that  we  may  consider  them  as  the  germ  of  this  production,  and  similar 


OF  THE  DIGESTIVE  SYSTEM. 


233 


to  that  which  arises  from  the  bottom  of  the  capsule  to  secrete  the 
osseous  substance  of  the  tooth. 

The  different  kinds  of  teeth  do  not  ossify  after  the  same  type  in  re- 
spect to  time  and  form.  The  internal  incisors  are  the  first,  and  the 
posterior  molar  teeth  the  last  to  appear.  In  regard  to  the  intermediate 
teeth,  the  deciduous  teeth  differ  from  the  permanent  teeth.  The  in- 
cisors and  the  canine  teeth  arise  by  one  small  point,  and  the  molar 
teeth  by  several,  viz.  the  small  by  two,  and  the  large  by  four  or  five. 
Each  point  always  possesses  a thin  triangular  form  on  its  appearance, 
which  is  the  constant  form  of  the  crown  of  the  canine  tooth.  • In  the 
incisor  and  molar  teeth  these  points  extend,  and  those  of  the  incisor 
teeth  present  two  small  accessory  points,  which  do  not  arise  by  special 
nuclei.  Among  the  different  points  of  the  canine  teeth  the  external 
and  the  anterior  are  developed  the  first,  and  next  the  internal.  In  the 
large  posterior  molar  teeth  the  anterior  external  is  first  seen,  then  the 
anterior  internal,  and  the  two  points  of  the  first  posterior  form  in  the 
same  order.  The  different  points  unite  according  to  the  same  law,  so 
that  judging  from  their  development,  the  large  molar  teeth  seem  to  be 
formed  by  two  smaller  teeth. 

The  inferior  arise  or  are  developed  before  the.  superior.  The  points 
of  the  anterior  deciduous  molar  tooth  are  already  united  to  the  lower 
jaw  in  the  full  grown  fetus,  while  this  is  not  the  case  in  the  upper  jaw. 
In  one  case  where  the  first  inferior  permanent  molar  tooth  presented 
five  osseous  points,  there  were  only  three  in  the  superior. 

§ 2118.  When  is  the  formation  of  the  tooth  completed?  It  is  not 
certainly  when  it  appears,  since  the  tooth  cuts  through  the  gum  before 
it  is  perfectly  developed  ; but  we  have  now  to  inquire  if  the  tooth 
' undergoes  any  other  internal  changes  after  the  root  is  perfectly 
formed. 

Those  who  maintain  this  fact  adduce  the  following  arguments  : 

1st.  The  change  in  the  tooth  in  animals  fed  with  madder. 

2d.  The  projection  of  one  tooth  above  the  rest,  when  the  corres- 
ponding tooth  in  the  opposite  jaw  is  extracted. 

3d.  The  union  of  fractured  teeth. 

Thp  following  arguments  have  been  adduced  in  favor  of  the  conti- 
nual reproduction  of  the  enamel  : 

4th.  The  pathological  changes  in  this  substance,  particularly  the 
black  spots,  which  do  not  reappear  after  being  removed  until  a new 
disease  supervenes.(l) 

5th.  The  duration  of  the  enamel,  which  cannot  be  explained  when 
we  consider  the  continual  friction  of  the  teeth,  except  by  admitting  it 
is  constantly  forming. (2) 

The  following  are  objections  to  these  different  arguments  : 

(1)  Hirsch,  loc.  cit.,  p.  17. 

(2)  Ibid. 


234 


descriptive:  anatomy. 


let.  The  coloring  of  the  hones  generally  by  madder  does  not  prove 
that  their  substance  is  constantly  reproduced.(l) 

2d.  Probably  we  have  less  right  to  admit  an  increase  in  the  size  of 
the  tooth  than  its  expulsion  from  the  alveolar  process.  Beside  the 
phenomenon  to  which  it  alludes  does  not  occur  in  man  or  in  most 
mammalia,  although  observed  in  some  of  them,  particularly  the 
gnawers, (2)  the  teeth  of  which  project  after  being  extracted  or  cut  off. 

3d.  The  union  of  fractures  of  the  teeth  does  not  prove  that  their 
substance  is  continually  reproduced,  but  only  that  in  some  cases  the 
germ  of  the  tooth  can  restore  a fractured  part  by  a process  analogous 
to  that,  when  at  the  commencement  it  secretes  the  osseous  substance 
in  every  part. 

4th.  It  is  nowhere  proved  that  the  enamel  is  formed  again  in  the 
pathological  cases  adduced. 

5th.  The  duration  of  the  enamel  depends  on  its  solidity. 

Thus  the  arguments  in  support  of  the  continual  formation  of  the 
teeth  in  general,  and  particularly  of  the  enamel,  are  by  no  means  con- 
clusive. On  the  contrary  the  second  fact  contradicts  it.  Beside  the 
mode  in  which  the  enamel  is  developed  does  not,  admit  this  theory. 

§2119.  Beside  the.  whole  duration  of  pregnancy,  a long  time  ad- 
vances, usually  six  months  after  birth,  before  the  teeth  appear,  at  least 
externally. 

During  this  period  we  find  in  the  place  afterward  occupied  by  them, 
a very  hard  and  in  fact  a cartilaginous  mass,  which  projects  and 
presents  numerous  grooves  some  lines  deep  and  entirely  different  from 
the  gum  ; this  arises  above  the  surface  of  the  alveolar  edges  and 
fulfills  the  function  of  the  teeth,  that  is,  it  serves  principally  to  retain 
the  nipple. 

This  substance  may  be  called  the  dental  cartilage  ( cartilago  den- 
tulis).  It  is  worthy  of  notice  as  analogous  to  the  horny  beak  of  birds 
and  reptiles.  It  disappears  as  the  teeth  are  developed  and  perforate 
the  gum. 

We  discover  in  this  substance,  particularly  in  the  region  of  the  molar 
teeth  and  on  its  inner  and  concave  side,  several  follicles  of  different 
sizes,  containing  a shining  and  yellowish  substance  ; these  are  at  most 
but  half  a line  in  diameter,  and  apparently  have  no  external  orifice. 
Serres  first  mentions  these  follicles. (3)  He  thinks  that  they  soften  the 
gum  of  the  child  before  the  teeth  appear,  and  afterwards  secrete  the 
tartar  of  the  teeth.  We  however  have  never  observed  them  until  the 
period  when  the  teeth  appear,  so  that  hitherto  we  have  considered 


(1)  B.  Gibson,  On  the  effect  of  madder-root  on  the  hones  of  animals  ; in  the  Mem. 
of  the  literary  society  of  Manchester,  2 d series,  vol.  i.,  p.  146-164. 

(2)  Lavaçna,  Osservaz.  sulla  carie  dei  dcnti,  Genoa,  1812. — Ondet,  Expériences 
sur  V accroissement  continu  et  la  reproduction  des  dents  chez  les  lapins , considérées 
sous  le  rapport  de  leur  application  à l'étude. de  l’organisation  des  dents  humaines  ; 
in  the  Journ.  dephys,  expér.,  vol.  iv.,  p.  70. 

(3)  Loc.  cit.,  p.  28-33,  pl.  4,  f.  6. 


OF  THE  DIGESTIVE  SYSTEM. 


235 


them  simply  as  new  formations,  caused  by  the  irritation  of  the  teeth 
which  are  soon  to  appear  ; they  probably  do  not  differ  in  their  nature 
from  abscesses. 

§ 2120.  The  triturating  surface  of  the  permanent  teeth,  like  that  of 
the  deciduous  teeth,  changes  more  or  less  during  life.  The  enamel  is 
gradually  used  by  friction  so  that  the  osseous  substance  is  exposed, 
and  the  triturating  substance,  formed  at  first  entirely  of  enamel,  pre- 
sents only  a layer  of  osseous  substance  when  the  cutting  edges  and 
the  pointed  summits  of  the  crowns  are  blunted.  When  the  tooth  is 
still  more  worn,  so  that  the  osseous  substance  is  destroyed  to  the 
dental  cavity  and  the  latter  is  open,  there  is  generally  formed  in  the 
same  proportion  at  the  summit  of  this  cavity  a brownish  substance  re- 
sembling bone,  but  a little  softer,  which  closes  the  opening  and  protects 
the  parts  within  the  cavity.(l)  These  phenomena  can  also  be  ad- 
duced against' the  opinion  of  those  who  assert  the  continual  reproduc- 
tion of  the  enamel. 

Nutrition  however  gradually  declines  in  the  teeth,  and  their  nutri- 
tious foramina  are  finally  obliterated.  Being  retained  in  the  alveolar 
processes  by  no  organic  attachment,  they  become  loose  and  fall  out. 
The  alveolar  processes  collapse  and  the  alveolar  edge  entirely  disap- 
pears after  the  gum  has  closed  the  alveolar  openings. 

b.  Special  remarks. 

§ 2121.  The  different  kinds  of  teeth  do  not  pass  through  the  dif- 
ferent periods  generally  mentioned  in  the  same  time,  but  very  irregu- 
larly and  more  or  less  in  succession.  We  may  mention  generally  : 

1st.  That  they  pass  through  the  different  periods  after  the  same 
law,  so  that  the  germ  of  the  tooth  in  which  the  follicle  first  appears  is 
also  the  fust  to  be  developed  and  ossified. 

2d.  That  the  synonymous  teeth  in  the  same  jaw  correspond  very 
exactly  in  this  respect. 

3d.  That  the  lower  teeth  are  developed  before  the  upper,  and  the 
anterior  before  the  posterior. 

4th.  That  the  gradual  development  of  the  human  teeth  corresponds 
to  permanent  forms  in  the  mammalia. 

1.  Deciduous  teeth. 

§ 2122.  The  deciduous  teeth,  in  accordance  with  the  first  law, 
appear  sooner  than  the  permanent  teeth.  The  period  at  which  their 
follicles  are  developed  and  the  order  in  which  these  latter  are  seen  have 

(1)  Hunter,  loc.  cit .,  p.  108. — Prochaska,  Obs.  de  decremento  dcnliwn  ; in  the 
Annot.  acad.jfasc.  I. 


236 


DESCRIPTIVE  ANATOMY. 


already  been  mentioned  above.  The  two  internal  follicles  are  those 
of  the  incisor  teeth,  and  the  external  those  of  the  molar  teeth  ; the  fifth 
intermediate  is  that  of  the  canine  tooth. 

Ossification  begins  at  the  fifth  month  in  the  inner  incisor  teeth,  a 
little  sooner  in  the  lower  than  in  the  upper.  Next  comes  the  external 
incisor  tooth,' then  the  anterior  molar  tooth.  About  the  end  of  the  fifth 
month  we  find  osseous  substance  in  these  three  teeth,  while  only  the 
germ  exists  in  the  other  two.  We  have  as  yet  been  unable,  to  deter- 
mine whether  the  canine  or  the  posterior  molar  tooth  is  ossified  first, 
because,  except  in  one  instance,  we  have  always  found  these  teeth 
with  or  without  traces  of  the  osseous  germ  at  the  same  time.  Pro- 
bably, however,  ossification  commences  first  in  the  former,  not  only 
because  we  have  once  found  in  it  an  osseous  germ,  while  there  was 
none  in  the  posterior  molar  tooth,  but  because  its  osseous  nucleus  has 
always  seemed  to  us  more  extensive  than  that  of  the  latter,  and  finally 
because  it  is  cut  first.  But  these  three  reasons,  particularly  the  last 
two,  do  not  establish  our  opinion  with  certainty. 

At  the  seventh  month  of  pregnancy  all  the  deciduous  teeth  contain 
osseous  nuclei. (1) 

The  number  and  arrangement  of  the  pieces  of  bone  which  form  the 
teeth  are  not  always  exactly  the  same. 

Hunter(2)  and  Rudolphi(3)  think  that  the  incisors  are  composed  of 
three  pieces,  a central  and  two  lateral  pieces,  which  are  smaller.  The 
canine  teeth  arise  by  a single  osseous  germ  according  to  Hunter  ; but 
Rudolphi  thinks  by  two  lateral  halves.  Both  admit  that  the  anterior 
molar  tooth  is  formed  of  an  anterior  portion  and  of  one  or  two  posterior 
pieces,  and  that  the  posterior  is  formed  by  an  anterior  germ  and  several 
posterior  nuclei.  Hunter  however  is  very  brief  on  this  subject,  al- 
though he  seems  to  speak  from  observation.  Rudolphi’s  assertions 
are  grounded,  not  on  researches  in  regard  to  the  development  of  the 
teeth  in  the  fetus,  but  upon  chemical  experiments,  having  for  their 
object  the  action  of  the  acids  on  perfect  teeth,  which  action  reduces 
them  to  the  number  of  pieces  mentioned  by  this  physiologist.  Nume- 
rous observations  on  the  fetus  have  convinced  us  that  the  canine  and 
the  incisor  teeth  are  developed  by  a single  germ,  which  arises  at  the 
centre  and  gradually  extends  to  the  sides.  We  cannot  then  consider 
as  natural,  conclusions  drawn  from  the  action  of  acids  on  perfect  teeth; 
and  farther,  because  other  writers,  as  Àlbinus,(4)  and  Blake, (5)  for- 
mally assert  that  the  incisor  and  the  canine  teeth  are  developed  by  one 
nucleus  of  ossification.  But  the  molar  teeth  in  fact  arise  by  several 

(1)  Blake  (Essai,  p.  23)  states  only  that  he  has  found  osseous  substance  in  all  the 
teeth  in  a fetus  of  eight  months. 

(2)  Loc.  cit.,  p.  88. 

(3)  lieber  die  Zähne  ; in  his  Anatomisch-physiologische  Untersuchungen,  p.  126. 

(4)  Ue  dentium  orlu  et  incrcmenlo  ; in  the  Annot.  acad„  book  ii.,  ch.  ii.,  p.  16. 

(5)  Loc.  cit.,  p.  6. 


OF  THE  DIGESTIVE  SYSTEM. 


237 


osseous  nuclei,  each  of  which  corresponds  perfectly  to  the  first  rudi- 
ment of  a single  incisor  or  canine  tooth. 

First  the  anterior  piece,  which  is  the  largest,  appears  ; this  corre- 
sponds peculiarly  to  the  incisors,  and  is  narrower  according  to  its 
height  than  it  is  afterwards.  Next  is  seen  the  posterior  piece,  which 
is  much  smaller  ; it  igradually  extends  and  unites  to  the  other  directly  or 
on  one  of  the  two  sides  by  a third  which  is  developed  at  a later  period. 
The  second  molar  tooth  arises  by  several  pieces,  at  least  three  and 
generally  four  in  number,  an  anterior,  two  lateral,  and  a posterior. 
The  anterior  piece  is  always  larger  than  the  others. 

All  the  pieces  except  the  small  one,  which  belongs  to  the  posterior 
molar  tooth,  are  usually  fused  at  birth. 

About  this  period  the  development  of  the  first  and  second  incisor 
tooth  is  nearly  equally  advanced  in  regard  to  the  whole  crown.  Next 
comes  the  anterior  molar  tooth,  the  crown  of  which  has  not  yet  how- 
ever acquired  all  its  height.  The  third  is  the  canine  tooth.  The 
most  imperfect  is  the  posterior  molar  tooth,  the  very  thin  crown  of 
which  presents  in  one  or  more  points  considerable  spaces  in  its  central 
portion,  and  a piece  which  is  entirely  distinct  from  the  others.  The 
posterior  molar  teeth  of  the  lower  jaw  not  unfrequently  form  a single 
piece  in  the  full  grown  fetus.  Beside  the  spaces  and  the  separation 
mentioned  disappear  in  the  two  jaws  in  the  first  few  months  after 
birth. 

The  cutting  of  the  deciduous  teeth  usually  commences  at  the  be- 
ginning of  the  seventh  month  after  birth.  The  lower  internal  incisors 
are  generally  first  seen  ; some  weeks  after,  the  upper  internal  incisors 
are  cut  ; one  or  two  months  afterward,  the  upper  and  lower  external 
incisors  ; at  the  end  of  the  first  year,  the  lower  anterior  molar  teeth  ; 
some  time  afterward,  the  upper  anterior  molar  teeth  ; at  the  age  of 
eighteen  months  the  inferior,  and  soon  after  the  superior  canine  teeth  ; 
toward  the  end  of  the  second  year,  the  posterior  molar  teeth  : so  that 
at  the  age  of  three  years  all  the  deciduous  teeth  are  seen. 

The  deciduous  teeth  receive  a distinct  artery,  which  comes  from  the 
dental  artery,  and  which  passes  through  a canal  in  the  jaw,  into  which 
it  enters  through  a special  foramen.(l) 

2.  Permanent  teeth. 

§ 2123.  The  permanent  teeth  are  developed  and  appear  nearly  in 
the  same  order  as  the  deciduous  teeth.  They  however  pass  through 
their  periods  much  more  slowly. 

We  observe  first  just  before  the  end  of  the  first  month  of  pregnancy 
the  follicle  of  the  anterior  molar  tooth.  Those  of  the  incisors  do  not 

(1)  Serres,  loc.  ciL,  p.  16. 

31 


VOL.  III. 


23S 


DESCRIPTIVE  ANATOMY. 


form  till  the  commencement  of  the  eighth  month  ; next  that  of  the 
Canine,  and  next  that  of  the  middle  great  molar  tooth.  That  of  the 
anterior  small  molar  tooth  forms  some  months  after  birth,  rarely 
betöre  the  seventh  or  eighth.  Next  appears  that  of  the  posterior 
small  molar  tooth,  and  usually  at  four  years  of  age  that  of  the  third 
great  molar  tooth,  which  is  situated  the  most  posteriorly.  The  os- 
seous germs  are  visible  nearly  at  the  same  time  as  the  follicles. 

Ossification  commences  in  the  anterior  great  molar  tooth.  Usually 
the  external  anterior  point  of  this  tooth  presents  at  the  end  of  the 
last  month,  of  pregnancy,  a small  osseous  piece, to  which  four  or 
five  others  are  gradually  attached  separately  ; these  do  not  unite  till 
the  end  of  the  first  year.  We  however  have  sometimes  found  in  a 
very  large  full  grown  fetus  five  points,  in  fact  entirely  distinct  from 
each  other,  the  posterior  of  which  was  still  very  small. 

All  the  permanent  teeth  have  not  the  same  situation  in  respect  to 
the  deciduous  teeth.  The  three  posterior  molar  teeth  are  situated  on 
the  same  range  as  these  latter,  but  farther  outward,  while  those  which 
should  be  properly  called  the  replacing  teeth  are  included  between 
them  and  the  posterior  wall  of  the  alveolar  processes,  the  incisors,  the 
canine  and  the  molar  teeth,  behind  those  to  which  they  correspond. 
The  follicles  of  the  permanent  teeth  are  at  first  contained  in  the  same 
alveolar  processes  as  the  old  teeth.  The  manner  in  which  they  are 
developed  is  very  curious.  They  leave  the  upper  and  posterior  part  of 
the  dental  follicles  already  existing,  so  that  they  may  be  considered  to 
a certain  extent  as  arising  from  these  latter  by  gemmation.  They  first 
rest  directly  on  them,  and  even  afterwards  when  they  are  elongated 
they  communicate  with  them  by  long  and  thin  cords. 

Our  observations,  however,  have  established  that  this  communica- 
tion is  only  between  the  external  layers  of  the  dental  follicles,  that  the 
internal  layers  are  much  more  essential,  and  entirely  distract  from  each 
other,  so  that  the  new  internal  dental  sac  is  developed  in  the  old,  be- 
tween it  and  the  external  layer,  although  their  cavities  are  uncon- 
nected. If  they  communicate,  it  must  have  been  at  a very  remote 
period,  since  we  have  never  been  able  to  discover  it  even  on  examining 
the  follicles  of  the  permanent  teeth  when  they  first  appear. 

The  new  sacs  are  gradually  separated  from  the  old  by  the  formation 
of  new  alveolar  cavities.  These  cavities  seem  at  first  slight  depres- 
sions in  the  posterior  wall  of  the  old  ; these  depressions,  like  the 
follicles,  are  much  shorter  than  these  latter,  and  extend  much  farther 
beyond  the  alveolar  edge  than  those  which  existed  previously.  A 
septum  gradually  arises  from  the  base  of  the  alveolar  processes,  and 
goes  towards  its  orifice.  The  two  alveolar  processes,  however,  con- 
tinue to  communicate  by  a considerable  opening,  through  which  passes 
the  cord  which  unites  the  two  sacs.  The  elongation  and  the  thinness 
of  this  cord  depend  on  the  increase  in  the  height  of  the  jaws. 

The  openings  between  the  incisors  and  the  canine  teeth  are  visible 
on  the  posterior  face  of  the  jaws.  That  of  the  internal  incisor  tooth 
corresponds  to  the  cavity  of  the  deciduous  internal  incisor  tooth.  That 


OF  THE  DIGESTIVE  SYSTEM, 


239 


of  the  external  is  situated  between  the  cavity  of  the  deciduous  external 
incisor  tooth  and  that  of  the  deciduous  canine  tooth.  That  of  the 
canine  tooth  is  situated  behind  the  cavity  of  the  deciduous  canine 
tooth.  The  communications  of  the  anterior  molar  teeth  with  the 
cavities  of  the  deciduous  molar  teeth,  are  not  visible  externally,  ac- 
cording to  several  anatomists,(l)  but  exist  at  the  bottom  of  those  latter; 
we,  however,  have  observed  that  they  are  situated  like  the  first,  on  the 
inside,  and  behind  the  alveolar  opening  of  the  deciduous  tooth,  and  that 
they  are  generally  narrower  than  the  others.(2)  The  follicles  of  the 
second  and  third  permanent  molar  teeth  emerge  in  the  same  manner, 
the  first  on  the  outside  of  the  deciduous  molar  tooth,  the  other  after- 
ward, on  the  outside  of  the  second.  The  foramina  of  communication 
between  their  cavities  are  situated  at  the  upper  part  of  the  septum 
which  separates  them.  As  the  jaw  and  the  deciduous  teeth  gradually 
arise  by  the  development  and  completion  of  their  roots,  as  the  per- 
manent teeth  which  replace  the  latter  do  not  increase  proportionally  in 
this  direction,  and  as  they  are  much  broader  than  the  deciduous  teeth, 
it  follows  that  they  are  situated  lower,  and  also  a little  on  the  outside 
of  them.  The  permanent  internal  incisor  teeth  are  situated  behind  the 
internal  and  a part  of  the  external  deciduous  teeth;  the  permanent  ex- 
ternal teeth  behind  these  latter  and  the  deciduous  canine  teeth  ; finally, 
the  anterior  molar  teeth  behind  the  deciduous  molar  teeth  and  between 
their  roots.  The  crowns  of  the  latter  nearly  touch  the  roots  of  the 
permanent  internal  incisor  teeth,  and  the  canine  teeth  are  on  the  out- 
side of  the  row,  more  remote  from  the  alveolar  edge,  and  are  carried 
farther  forward  than  the  others. 

§ 2124.  At  the  age  of  six  or  seven  years  the  second  dentition  com- 
mences ; the  deciduous  teeth  fall  out  and  the  permanent  teeth  appear. 
At  this  time  the  artery  of  the  deciduous  teeth  and  its  canal  disappear 
more  or  less  perfectly, (3)  so  that  the  dental  capsules  receive  no  more 
nutritious  fluid.  Usually,  and  in  fact  almost  always,  the  permanent 
anterior  molar  teeth  begin  to  appear  before  the  time  of  the  second 
dentition,  which  has  deceived  some  writers,  and  led  them  to  admit 
twenty-four  deciduous  teeth.  Among  the  teeth  which  alone  deserve 
to  be  called  permanent  teeth,  the  inferior  internal  incisor  teeth  usually 
appear  first.  Next  come  the  superior  internal,  then  the  external  ; after- 
ward, and  usually  at  the  age  of  from  thirteen  to  fourteen  years,  and 
almost  always  at  the  same  time,  the  canine  and  the  middle  great  molar 
teeth  appear  ; finally,  at  a variable  period,  between  sixteen  and  twenty 
years,  and  sometimes  later,  the  last  great  molar  teeth  appear,  which 
are  hence  called  the  wisdom  teeth  ( dentes  sapientice).  Thus,  although 
the  permanent  canine  teeth  appear  much  sooner  than  the  small  molar 
teeth,  they  however  normally  are  cut  afterward,  between  the  appear- 
ance of  these  latter  and  the  posterior  molar  teeth,  exactly  as  the  deci- 

(1)  Albinus,  loc.  cit.,  p.  13-15.— Blake,  loc.  cit..  p.  40.— Serres,  loc.cit.  p.  38. 

(21  Meckel,  loc.  cit. 

(3)  Serres,  loc.  cit.  p.  19. 


240 


DESCRIPTIVE  ANATOMY. 


duous  canine  teeth  appear  in  the  jaws  between  the  two  deciduous 
molar  teeth.  <e- 

The  order  then  in  which  the  teeth  are  cut,  is  nearly  the  same  for  the 
deciduous  and  the  permanent  teeth. 

Both  resemble  formations  which  are  permanent  in  animals. 

The  appearance  of  the  incisors  before  the  others  deserves  notice,  as 
it  resembles  the  development  of  the  intermaxillary  bone,  and  the  cor- 
responding- middle  portion  of  the  lower  jaw  which  exist  particularly 
in  fishes,  and  more  or  less  in  all  animals.  The  earlier  development  of 
the  lower  represents  remarkably  the  formation  of  the  ruminantia,  and 
the  regular  existence  of  the  incisors  and  the  molar  teeth  without  the 
canine  teeth  in  the  rodentia. 

The  deciduous  teeth  change  in  certain  respects  before  falling  out. 
Their  roots  disappear  ; they  become  both  shorter  and  thinner,  so  that 
their  inner  part  diminishes  as  they  terminate  more  or  less  in  a point. 

The  more  or  less  narrow  canal  in  which  the  cavity  of  the  per- 
manent tooth  is  first  situated,  gradually  enlarges,  as  wTell  as  its  orifice, 
as  the  tooth  advances  ; finally,  the  septum  which  seperates  the  alveolar 
process  of  the  permanent  tooth  from  that  of  the  deciduous  tooth,  is  de- 
stroyed, and  the  two  teeth  are  then  situated  in  the  same  cavity  as  they 
were  originally,  with  this  difference,  however,  that  the  permanent 
tooth,  from  its  greater  size,  always  penetrates  partly  into  the  alveolar 
process  of  the  adjacent  deciduous  tooth. 

The  destruction  of  the  root  of  the  deciduous  tooth  doubtless  depends 
on  the  mechanical  action  of  the  permanent  tooth  upon  it,  in  accordance 
with  the  law,  that  long  continued  pressure  on  a part,  causes  it  to  dis- 
appear by  obstructing  nutrition,  or  by  accelerating  the  destructive  pro- 
cess. This  is  proved  not  only  by  the  disappearance  of  the  deciduous 
tooth,  but  also  by  the  well  known  fact  that  those  temporary  teeth 
which  are  not  replaced  by  the  permanent  teeth,  continue  very  long 
even  in  the  adult,  and  sometimes  even  during  existence^  1)  Although 
the  tooth  which  continues  longer  than  usual  often  finally  falls  out, (2) 
we  must  not  conclude  that  the  permanent  teeth  have  no  effect  in  the 
normal  state  independent  of  their  influence,  but  only  that  the  decidu- 
ous teeth  from  their  primitive  destination,  exist  so  short  a time  that 
this  action  is  not  absolutely  necessary  to  determine  their  decay. 
Finally,  the  continuance  of  the  deciduous  teeth  even  after  their  vessels 
and  nerves  have  completely  disappeared,  is  favored  by  the  adhesions 
between  their  root  and  the  inner  face  of  the  alveolar  process. (3) 

The  permanent  tooth  causes  the  decay  of  the  deciduous  tooth  prin- 
cipally by  pressing  upon  the  vessels  and  nerves  of  this  latter,  and  like- 
wise its  adhesions  with  the  alveolar  process,  and  destroying  them. 
The  destruction  of  the  root  is  not  indispensible,  nor  even  constant,  as 
the  deciduous  teeth  are  sometimes  shed,  preserving  their  roots  entire. (4) 

(1)  Hunter,  loc.  cit.,  p.  99. — Hudson,  in  Blake,  p.  67. — Fox,  loc.  cit.,  p.  40. 

(2)  Fox,  loc.  cit. 

(3)  Serres,  loc.  cit.,  p.  97, 

(4)  Idem,  loc.  cit.,  p.  102. 


OP  THE  DIGESTIVE  SYSTEM. 


241 


This  is  the  proximate  cause  of  the  loss  of  the  tooth,  and  not,  as  has 
been  asserted,  the  space  formed  by  the  disappearance  of  the  septum 
between  the  alveolar  processes,  the  only  effect  of  which  space  would 
be  to  fix  the  tooth  less  firmly.(l)  In  fact,  there  is  no  space,  since  the 
permanent  tooth,  in  proportion  as  it  destroys  the  septum,  prevents  the 
space  from  forming,  as  it  enters  the  alveolar  process  of  the  deciduous 
tooth. 

§ 2125.  From  our  preceding  remarks  it  follows,  that  the  teeth  re- 
semble the  bones  generally  in  their  chemical  composition  and  hardness. 
They  however  differ  from  them  in  these  two  respects  : 

1st.  They  are  harder. 

2d.  Their  tissue  is  much  more  solid. 

3d.  They  are  composed  of  two  substances. 

4th.  They  contain  a much  greater  proportion  of  earthy  salts. 

They  differ  also  from  the  bones. 

5th.  They  are  unattached  in  most  of  their  extent. 

6th.  In  their  mode  of  connections  with  the  rest  of  the  body,  and  in 
their  relations  with  the  germ  of  the  tooth. 

7th.  In  their  mode  of  development. 

8th.  Because  they  do  not  participate  in  the  diseases  of  the  osseous 
system. 

9th.  They  receive  no  vessels. 

10th.  They  resist  much  more  the  action  of  chemical  agents  and 
spontaneous  decomposition  after  death. 

In  all  these  respects,  on  the  contrary,  they  are  very  similar  to  the 
epidermoid  parts,  which  analogy  is  confirmed  by  comparative  ana- 
tomy.(2) 

(1)  Serres,  loc.  cit.,  p.  104. 

(2)  Mayer  and  Kathoven  are  the  first  who  arranged  the  teeth  as  belonging  to  the 
horny  system,  which  has  been  followed  by  Heusinger,  but  opposed  by  Rudolphi,  but 
very  wrongly.  Bonn  (De  contin.  membran.,  1763,  § 1 6),  Walther  ( Physiologie , vol. 
i.  p.  176),  and  Lavagna  (loc.  cit.,  p.  164),  had  already  mentioned  the  analogy  between 
the  teeth  and  the  hairs.  This  point  of  doctrine  had  been  carefully  developed  by 
Lavagna,  and  afterwards  by  Heusinger.  The  reasons  alledged  by  the  latter  are,  1st. 
The  teeth  in  the  different  mammalia  present  imperceptible  transitions,  from  those 
which  are  most  similar  to  the  bones,  to  the  different  parts  of  the  horny  system,  par- 
ticularly the  nails,  the  horns,  and  the  hairs.  2d.  The  teeth  of  several  of  the  mam- 
malia have  a lamellar  texture  like  the  nails  and  the  horns,  and  this  texture,  although 
very  evident  in  all,  sometimes  seems  effaced  from  the  greater  accumulation  of  the 
earthy  salts.  3d.  The  development  of  the  teeth  is  very  similar  to  that  of  the  nails 
and  horns.  4th.  Certain  teeth  are  shed  and  reproduced,  as  are  also  the  nails  and  the 
horns.  5th.  The  teeth  are  not  nourished,  they  are  formed  entirely  of  one  piece,  and 
the  substance  which  forms  them  is  not  renewed.  These  views  are  in  part  those  of 
Coiter,  Hérissant,  Cuvier,  and  Serres.  G.  F.  St.  Hilaire  has  adopted  them  entirely. 
The  tooth,  he  says,  ti  produced  by  transudation  ; it  is  an  inorganic  body,  anatomi- 
cally speaking,  a mass  composed  of  several  layers,  in  which  there  is  nothing  to  be 
compared  with  osseous  tissue.  But  this  naturalist  has  extended  these  ideas  very 
much  by  demonstrating  that  we  must  refer  the  beak  of  birds  to  the  formation  of  the 
teeth,  a curious  fact,  and  one  of  the  highest  importance,  which  fully  justifies  the 
analogy  established  between  this  formation  and  the  epidermoid  tissue.  He  advances 
also  another  idea,  which  we  shall  mention  here  briefly,  although  connected  with  im- 
portant physiological  considerations,  it  is  foreign  to  this  work,  viz.  that  if  the  teeth 
afterwards  serve  for  mastication,  it  is  fortunate  for  those  animals  who  possess  and 


242 


DESCRIPTIVE  ANATOMY. 


B.  ABNOnMAL  STATE. 

§2126.  The  teeth  not  unfrequently  vary  from  the  normal  state  ; 
and  most  generally  present  anomalies  in  their  texture.  The  most  fre- 
quent alterations  of  texture  are  those  which  relate  to  the  period  of 
development  and  the  order  in  which  it  occurs  ; next,  those  which  relate 
to  the  number  of  the  teeth.  Next  come  the  anomalies  in  situation  and 
direction,  and  finally  those  in  form,  size,  and  continuity  of  tissue. 

a.  Deviations  of  formation. 

§2127.  1st.  Anomalies  in  the  development.  These  are  the  slightest. 
Not  unfrequently  all  the  teeth,  or  some  of  them  only,  appear  unusually 
late.  This  is  seen  particularly  in  the  last  molar  teeth,  in  regard  to 
which  we  should  remark,  that  their  unusually  late  appearance  is  only 
■an  extension  of  time  between  their  appearance  and  that  of  the  other 
teeth,  as  between  the  appearance  of  these  latter  compared  together. 
It  is  less  common  for  all  or  some  of  the  teeth  to  appear  sooner  than 
usual  ; sometimes,  however,  children  are  born  with  several  teeth.  It 
is  curious,  although  the  fact  agrees  veiy  well  with  the  laws  and  the 
other  phenomena  of  vegetative  life,  that  this  early  development 
seems  evidently  to  be  favored  by  the  longer  continuance  of  the  fetus  in 
the  uterus,  since  in  a proportionally  great  number  of  children  who  had 
continued  in  the  fetal  state  some  weeks  beyond  the  common  period, 
teeth  existed  at  birth. 

We  must  mention  among  the  anomalies  in  the  development,  the 
continuance  of  the  deciduous  teeth  beyond  the  usual  period,  which 
does  not  necessarily  oppose  the  appearance  of  the  permanent  teeth, 
and  causes  so  much  irregularity  in  their  arrangement  and  situation, 
that  we  are  led  at  first  view  to  believe  the  number  of  the  teeth  to  be 
increased.  But  the  deciduous  teeth  frequently  remain,  although  the 
permanent  teeth  do  not  appear,  and  this  anomaly  must  even  be  attri- 
buted to  the  absence  of  these  latter. 

Beside  these  differences  in  the  development  which  relate  to  the 
quantity,  there  are  others  dependent  on  the  quality.  Thus,  sometimes 
all  the  lower  incisor  teeth  appear  before  one  of  the  upper  is  seen.  It  is 
much  more  rare  that  the  superior  incisors  appear  before  the  inferior, 
the  external  before  the  internal,  the  anterior  molar  teeth  before  the  ex- 
ternal incisors,  and  the  posterior  before  the  canine  teeth.(l)  The  rarest 
case  is  where  the  canine  teeth  appear  before  the  anterior  molar  teeth, 

profit  by  them,  but  that  when  the  formations  of  the  teeth  begin  to  appear  in  the  fetus, 
they  are  real  organs  of  the  fetus  ; in  this  sense  they  arise,  like  all  the  organs  of  sense 
to  form  a termination  to  the  circulatory  system  of  the  advanced  parts  of  the  head, 
tojlimit  a certain  number  of  vascular  trunks.  F.  T. 

(1)  Blake,  p.  25.— Fox,  loc.  cit.,  p.  7. — Serres,  p.  85. 


OF  THE  DIGESTIVE  SYSTEM. 


243 


although  several  authors  mention  this  as  the  normal  order,  or  at  least 
state  it  to  be  as  frequent  as  that  mentioned  above. (1) 

2d.  Anomalies  in  the  number.  These  teeth  which  most  frequently 
appear  later  than  the  common  period,  the  posterior  molar  teeth,  are 
also  those  which  are  most  commonly  deficient.  Instances,  however, 
are  known  of  the  deficiency  of  every  tooth. (2)  In  one  subject  there 
were  only  four  permanent  teeth  in  each  jaw.  In  another  there  was 
only  one  incisor  in  the  upper  jaw.  Sometimes  the  teeth  have  been 
entirely  deficient. (3) 

It  is  more  rare  to  find  an  excess  than  a deficiency  of  teeth.  This 
anomaly,  leaving  out  of  view  that  which  is  only  apparent,  and  which 
we  have  just  mentioned,  appears  principally  under  two  different  forms. 
Sometimes  the  supernumerary  teeth  exist  simultaneously  with  the 
others;  sometimes,  however,  they  appear  after  them. 

In  the  first  case  they  make  part  of  the  same  range  with  the  others  ; 
sometimes  are  found  out  of  this  range,  so  that  when  several  exist  they 
form  a second  series.  They  are  generally  situated  behind  the  normal 
teeth,  that  is,  the  same  relation  exists  between  them  and  these  latter 
as  between  the  deciduous  and  the  permanent  teeth.  This  anomaly 
varies  in  the  same  manner  as  that  which  depends  on  the  abnormal 
situation  of  the  teeth  in  general. 

The  first  degree  of  the  redundancy  of  the  teeth  is  the  development 
of  one  or  more  rounded  eminences  on  the  sid'es  of  the  crown  ; hence 
are  formed  what  are  termed  the  dentes  proliferi.( 4)  This  anomaly 
seems  to  belong  almost  exclusively  to  the  molar  teeth,  and  it  is  curious 
as  it  is  a greater  development  of  one  of  their  peculiar  characters,  the 
existence  of  several  points  on  their  crown. 

The  anomaly  is  still  greater  when  other  smaller  separate  teeth  exist 
on  a normal  tooth,  and  which  are  seemingly  formed  by  special  germs. 
In  the  only  case  of  this  anomaly  known  to  us,  and  which  existed  on 
a canine  tooth,  there  were  three  accessory  teeth  ; these  small  teeth 
were  much  smaller  than  the  normal  canine  teeth,  but  were  all  formed 
after  the  same  type  ; they  rested  on  the  base  of  the  crown  and  had 
the  same  direction. (5) 

The  supernumerary  teeth  are  observed  most  frequently  in  the  upper 
jaw  and  forward,  near  the  canine  teeth  and  the  incisors.  This  pecu- 
liarity is  very  remarkable,  since  in  several  animals  the  anterior  teeth 
are  more  numerous  in  the  upper  than  in  the  lower  jaw.  They  usually 

(1)  Miel,  Bull,  de  la  soc.  méd.  d'èmul.,  1817,  p.  94. 

(2)  Fox  mentions  several  instances  of  this. 

(3)  Fox.  loc.  cit., — Sabatier,  Anat.,  vol.  i.  p.  78. 

(4)  Bartholin,  Hist.  anat.  rar.,  ch.  i.,  p.  49. — Serres,  loc.  cit.,  p.  160. — Linden, 
Medic,  phys.,  cap.  xiii.,  art.  3. — Oudet,  Bull,  de  la  fac.  de  méd.,  1821,  no.  i.,  p.  369. 
— G.  Saint  Hilaire  has  described  and  figured  one  of  these  teeth  ( Syst . dentaire  des 
mammif.  et  des  oiseaux,  p.  77,  pl.  i.,  fig.  18). 

(5)  Lemaire,  Deux  observations  d'anatomie  pathologique  sur  les  dents;  in  the 
Journ.  de  méd.,  vol.  xxxvi.,  p.  252. 


244 


DESCRIPTIVE  ANATOMY. 


differ  from  all  tlie  normal  teeth  in  form  and  size,  being  smaller  and 
conical,  sometimes  bicuspid.  When  they  occur  at  the  posterior  part 
of  the  mouth  they  do  not  resemble  the  wisdom  teeth.  Their  number 
varies.  Generally  they  are  few,  but  sometimes  they  are  many  ; in 
one  case  even  the  whole  number  of  teeth  was  seventy-two,  viz.  eight 
incisors,  four  canine  and  twenty-four  molar  teeth  in  each  jaw.(l)  Pos- 
sibly, however,  this  statement  is  not  perfectly  correct,  and  should  be 
considered  only  as  an  instance  of  the  coexistence  of  the  deciduous  and 
permanent  teeth.  Sometimes  also  when  the  number  T>f  teeth  is  unu- 
sually large,  this  anomaty  is  caused  by  the  division  of  one  or  more 
into  several. 

The  second  mode  in  which  the  number  of  teeth  is  increased  has 
been  termed  the  third  dentition.  There  is  even  sometimes  a fourth 
dentition,  although  the  instances  mentioned  of  this  are  hardly  credible. 
The  principal  circumstances  of  this  remarkable  phenomenon  are  as 
follow  : 

a.  The  third  dentition  is  attended  with  the  same  symptoms  as  those 
of  the  first  and  second.  The  new  teeth  are  smaller  than  those  they 
replace  ; they  are  less  permanent  and  soon  decay. 

b.  The  period  of  their  formation  is  not  determined.  If  we  may 
judge  of  them  from  some  facts,  they  are  formed  before  they  appear  : 
probably,  however,  individuals  differ  in  this  respect. 

c.  The  third  dentition  usually  occurs  at  a very  advanced  period  of 
life. 

d.  The  time  between  the  third  and  second  dentition  varies.  Ge- 
nerally, however,  the  third  teeth  appear  shortly  after  the  second 
decay. 

e.  In  this  respect  there  are  differences,  some  of  which  depend  on 
the  quantity,  others  on  the  quality.  Usually  however  one  or  more 
teeth  are  replaced  more  frequently  than  all.  The  posterior  molar 
teeth  seem  to  be  those  which  are  renewed  most  frequently,  and  even 
if  this  be  not  true  it  is  a fact  that  when  they  are  replaced  by  others 
the  same  phenomena  are  presented  as  at  the  second  dentition. 

3d.  Anomalies  in  situation  and  direction.  They  differ  conside- 
rably : 

a.  Situation.  In  this  respect  the  teeth  are  rarely  abnormal,  and  if 
they  are  situated  in  the  range  they  change  their  place,  so  that  this 
anomaly  belongs  to  the  history  of  the  lateral  inversion.  Thus  the 
canine  tooth  sometimes  exists  between  the  two  incisors.  In  other 
cases  the  canine  tooth  is  replaced  by  the  first  anterior  molar  tooth,  and 
exists  between  it  and  the  second.(2)  Sometimes  also  the  teeth  are 
developed  in  parts  of  the  jaws  where  they  are  not  generally  found. 
These  abnormal  teeth  are  seen  most  frequently  in  the  palatine  process 

(II  Arnold,  Obs.  phys.  tried.,  p.  69. 

(2)  Miel,  Observation  sur  un  cas  très  rare  de  transposition  des  denis  ; in  the  Journ. 
de  méd.,  vol.  xl.,  1817,  p.  88. 


OF  THE  DIGESTIVE  SYSTEM. 


245 


of  the  upper  maxillary  bone,  directly  or  at  some  distance  behind  the 
normal  teeth.  They  are  in  the  lower  jaw  principally  situated  in  its 
angle.  The  narrowness  of  the  jaw  causes  them  to  project  above  the 
others,  and  their  direction  is  also  less  perpendicular. 

b.  Direction.  Not  unfrequently  the  teeth  are  oblique,  which  de- 
pends particularly  on  the  narrowness  of  the  jaw  ; but  here  their  faces 
look  to  the  sides,  and  their  edges  are  turned  backward  and  forward. 
They  are  rarely  on  the  contrary  reversed,  that  is,  the  summits  of  their 
roots  look  to  the  alveolar  edge  and  the  crowns  to  the  opposite  region 
of  the  jaw. 

4th.  Anomalies  in  the  form.  The  form  of  the  teeth  is  abnormal  in 
a great  many  different  modes. 

a.  In  regard  to  the  xvhole  tooth , this  abnormal  formation  is  indicated 
by  the  adhesion  of  two  adjacent  teeth  ; this  sometimes  extends  their 
whole  distance,  and  is  sometimes  confined  to  a portion  of  their  extent, 
generally  to  the  roots.(l) 

b.  Crown.  The  form  of  the  triturating  surface  of  the  crown  some- 
times varies  very  much  from  the  common  form. 

The  first  great  molar  tooth  seems  particularly  to  have  a peculiar 
tendency  to  the  imperfect  development  of  this  surface  ; for  we  have 
sometimes  found  it  on  each  side  in  both  jaws  with  a great  number  of 
small  eminences,  a curious  analogy  with  the  molar  teeth  of  the  hog. 

The  rest  of  the  crown,  instead  of  being  smooth  as  usual,  some- 
times presents  rounded,  transverse,  and  longitudinal  elevations  and 
depressions,  which  depend  on  a deficiency  in  the  secretion  of  the 
enamel.(2) 

The  crown  more  rarely  presents  so  irregular  a form  that  it  appears 
to  be  compressed  from  above  downward  and  reversed.  (3) 

c.  Roots.  The  roots  are  abnormal  more  frequently  than  the  crowns. 
Their  principal  anomalies  are  an  excess  in  number  and  a variation  in 
direction. 

Sometimes,  although  very  rarely,  the  superior  molar  teeth  have 
five  roots, (4)  and  the  inferior  «four. (5)  More  frequently  these  latter 
have  three.  In  some  subjects  we  find  two  in  the  canine  teeth  and 
more  rarely  in  the  incisors. (6) 

In  the  abnormal  direction  of  the  roots  of  the  teeth  they  are  curved 
very  much  in  the  form  of  a hook, (7)  or  they  are  oblique.  These  two 
anomalies  are  most  frequent,  particularly  in  the  great  molar  teeth, 
which  they  render  more  solid. 


(1)  Fox,  loc.  cit.,  tab.  viii.,  fig.  8-11. 

(2)  Idem,  loc.  cit.,  tab.  viii.,  fig.  14. 

(3)  Idem,  loc.  cit.,  tab.  viii.,  fig.  11,  12. 

(4)  Idem,  loc.  cit.,  fig.  13. 

(5)  Idem,  loc.  cit.,  fig.  11. 

(6)  Tesmer,  Obs.  ostcol.,  vol.  i.,  fig.  1-4. 

(7)  Lemaire,  loc.  cit.,  p.  254. 

32 


Vol,  III. 


246 


DESCRII'TIVE  ANATOMS’, 


5th.  Anomalies  in  size.  The  upper  internal  incisors  are  principally 
abnormal  in  this  respect  from  a primitive  deviation  of  formation,  being- 
much  larger  than  usual.  But  the  size  and  mass  of  the  teeth  may  also 
be  increased  or  diminished  from  too  great  or  too  slight  activity  in  the 
formative  power. 

The  roots  particularly  increase  in  size,  being  affected  with  hyperos- 
tosis. (1)  Sometimes,  although  more  rarely,  the  crown  is  unusually 
large.  We  must  also  mention  here  the  formation  of  a bony  substance 
in  the  earthy  of  the  tooth,  which  sometimes  adheres  to  the  parietes 
and  sometimes  is  developed  in  the  centre  of  the  soft  pulp  which  fills 
this  cavity. (2) 

Atrophia  is  the  opposite  of  hyperostosis  ; when  it  takes  place  in  the 
crown  it  sometimes  does  not  extend  beyond  the  enamel,  or  at  least  it 
begins  with  the  layer  of  enamel,  although  it  extends  gradually  to  the 
osseous  substance.  This  latter  is  unaltered  in  its  texture,  and  the 
cavity  of  the  tooth  is  not  exposed.  The  anterior  teeth  are  more  sub- 
ject to  this  disease,  which  attacks  only  their  anterior  face  and  is  seen 
particularly  in  scrofulous  subjects. 

6th.  Solutions  of  continuity.  The  fractures  of  the  teeth  rarely  su- 
pervene unless  preceded  by  an  alteration  of  texture,  which  renders 
these  parts  brittle.  In  this  case,  whether  the  scale  be  detached  or 
there  is  simply  a fissure,  the  solution  of  continuity  does  not  close,  while 
it  is  perfectly  healed  even  when  there  is  a loss  of  substance,  when  the 
tooth  is  perfectly  healthy.  The  latter  applies  equally  to  transverse 
and  longitudinal  fractures. 

The  fractures  of  the  roots,  however,  alone  are  consolidated.  Those 
of  the  crowns  do  not  heal,  which  undoubtedly  depends  on  the  fact  that 
union  takes  place  by  an  exudation  of  osseous  substance  on  the  outer 
face  of  the  germ  of  the  tooth,  in  accordance  with  the  law  of  the  normal 
formation  of  the  tooth.  It  appears  then  from  this,  that  the  external 
membrane,  termed  the  periosteum  of  the  tooth,  takes  no  more  part  in 
the  cicatrization  than  in  the  primitive  formation  of  the  tooth.(3) 

• 

6.  Alterations  of  texture. 

§ 2128.  The  alterations  in  the  texture  of  the  teeth  are  : 

1st.  Caries.  It  is  the  most  common.  It  usually  proceeds  from  with- 
out inward,  more  rarely  from  within  outward,  begins  by  the  destruction 
of  the  enamel,  and  seldom  extends  beyond  the  crown.  It  attacks  the 
molar  teeth  most  frequently.  It  is  rarely  or  never  observed  at  an  ad- 
vanced age. 


(1)  Fox,  loc.  cit .,  tab.  i. 

(2)  Duval,  Cons.  mid.  sur  les  dents  ; in  the  Journ.  de  mid.,  vol.  xxxvi.  ; Bull,  de 
lafac.  de  mid.,  p.  101. 

(3)  Duval,  Sur  la  consolidation  des  fractures  des  dents;  in  the  Journ.de  mid., 
vol.  xiii.,  p.  275. 


OF  THE  DIGESTIVE  SYSTEM. 


247 


Sometimes  the  germ  inflames,  suppurates,  and  dies,  independent  of 
the  solid  substance  of  the  tooth. (1)  Its  inflammation  seems  to  precede 
the  caries  of  the  tooth. (2) 

2d.  The  teeth  rarely  participate  in  the  general  softening  of  the 
bones. 

3d.  The  formation  in  the  alveolar-  processes  of  cysts  filled  with 
a liquid  sometimes  serous  and  sometimes  thicker  than  serum.  These 
cysts  partially  destroy  the  root  of  the  tooth. 

The  gum  frequently  softens,  and  then  bleeds  at  the  least  touch. 

The  abnormal  swelling  of  this  tissue  with  softening  constitutes 
epulis,  which  term  embraces,  however,  very  different  alterations  of 
texture. 


II.  CERVICAL  AND  THORACIC  PORTIONS  OF  THE  ALIMENTARY  CANAL. 

§ 2129.  The  cervical  and  thoracic  portion  of  the  alimentary  ca- 
nals) are  much  more  simple  than  the  cephalic.  They  include  the 
pharynx  and  the  esophagus.  The  first  begins  at  the  posterior  extre- 
mity of  the  cavities  of  the  mouth  and  nose,  and  is  uninterruptedly 
continuous  with  the  esophagus,  which  is  connected  with  the  stomach. 


A.  PERFECT  STATE. 


I.  PHARYNX. 


§ 2130.  The  pharynx^ 4)  extends  in  a straight  line  from  the  base  of 
the  skull  and  the  fauces  to  the  lower  extremity  of  the  larynx,  or  to  the 
fifth  cervical  vertebra.  Its  mean  measure  is  four  inches  long,  and  one  in 
diameter  at  its  broadest  part  when  moderately  distended.  Below  this 
point  it  contracts,  then  dilates  again,  becomes  narrower,  and  is  finally 
continuous  with  the  esophagus. 

Its  posterior  straight  face  is  situated  directly  before  the  five  superior 
cervical  vertebras  and  the  anterior  muscles  of  the  neck,  behind  the  ca- 
vity of  the  mouth  and  the  larynx,  between  the  great  vascular  and 
nervous  trunks  of  the  neck. 

Its  upper  extremity  or  arch  ( fornix ) is  united  by  some  cellular  tissue 
to  the  lower  face  of  the  body  of  the  basilar  bone  and  the  petrous  por- 
tion of  the  temporal  bone.  Some  muscles  to  be  described  hereafter 

(1)  Duval,  loc.  cit.,  vol.  xxxvi.,  p.  99,  100. 

(2)  Serres,  loc.  cit.,  p.  51. 

(3)  Fabricius  of  Aquapendente,  De  gulâ  et  ventriculo,  Padua,  1618. — J.  Fantoni, 
De  gulâ  et  ventriculo,  Turin,  1742. 

(4)  Santorini,  De  phavjnge  ; in  the  Ohs.  anat.,  cap.  vii. 


248 


DESCRIPTIVE  ANATOMY. 


attach  it  to  different  parts  of  the  head.  Upward  and  backward  are 
the  posterior  nostrils,  forward  the  orifice  of  the  cavity  of  the  mouth, 
backward  and  on  the  sides  those  of  the  Eustachian  tubes.  These 
different  openings  exist  at  its  upper  part,  which  is  divided  by  the  soft 
palate  to  a certain  extent  into  an  anterior  and  a posterior  passage. 

§ 2131.  It  is  surrounded  externally  by  a thin  layer  of  cellular  tis- 
sue, which  attaches  it  loosely  to  the  adjacent  parts.  Below  this  layer 
is  another,  which  is  easily  separated  from  it  ; this  is  also  cellular  and 
is  filled  with  fat,  and  intimately  unites  it  with  the  subjacent  muscular 
layer.  The  nervous  and  vascular  trunks  which  enter  into  the  proper 
membranes  of  the  pharynx  are  distributed  in  them. 

§2132.  The  muscular  tunic  of  the  pharynx  is  formed  principally 
by  the  three  constrictor  muscles  (J\I.  conslrictores  pharyngis),(l)  a 
superior , a middle , and  an  inferior.  These  muscles  have  several  com- 
mon characters,  which  are  : 

1st.  They  surround  the  pharynx  backward  and  on  the  sides  ; their 
lateral  extremities  are  attached  to  the  adjacent,  hard  parts  before  the 
pharynx,  especially  to  several  bones  of  the  face  and  skull,  to  the  hyoid 
bone  and  to  the  larynx. 

2d.  They  are  composed  of  fibres  which  proceed  from  below  upward 
and  from  without  inward,  and  which  extend  by  radiation  from  each 
side  to  the  median  line. 

3d.  They  partially  cover  each  other  from  below  upward. 

4th.  They  are  voluntary  muscles. 


A.  CONSTRICTOR  PHARYNGIS  INFERIOR. 

§ 2133.  The  constrictor  pharyngis  inferior  or  the  crico-thyreo- 
pharyngcus  muscle  arises  by  from  two  to  four  triangular  digitations, 
from  the  cricoid  and  the  thyroid  cartilages. 

The  lowest  and  smallest  is  attached  below  the  crico-thyroideus 
muscle  to  the  lower  part  of  the  side,  and  to  the  lower  part  of  the  pos- 
terior horn  of  the  cricoid  cartilage. 

The  upper,  the  larger,  is  sometimes  single  and  sometimes  triple  ; it 
arises  from  all  the  posterior  part  of  the  side  of  the  thyroid  cartilage, 
excepting  the  lower  region  occupied  by  the  crico-thyroideus  muscle, 
which  is  situated  between  it  and  the  lowrer  digitation. 

The  fibres  of  this  muscle  proceed  from  all  these  points,  divided  into 
several  fasciculi  in  a greater  or  less  extent,  and  go  toward  the  median 
line,  so  that  the  inferior  are  almost  transverse,  while  the  others  ascend 
more  the  higher  they  become,  and  unite  at  angles  more  and  more 
acute  with  those  of  the  opposite  side  on  the  median  line. 


(1)  Santorini,  Septcmdccim  tabula tab.  vi. 


OF  THE  DIGESTIVE  SYSTEM. 


249 


The  upper  head  of  this  muscle  is  only  about  an  inch  below  the 
upper  extremity  of  the  pharynx. 

B.  CONSTRICTOR  PHARYNGIS  MEDIUS. 


§ 2134.  The  constrictor  pharyngis  médius  muscle  (JVT.  constrictor 
médius  pharyngis,  s.  glosso-hyo-pharyngeus,  s.  kerato-chondro  pharyn- 
geus , s.  cephalo-pharyngeus)  is  much  smaller  and  weaker  than  the 
preceding.  It  arises  from  the  hyoid  bone  and  the  tongue,  generally 
by  two  heads.  The  inferior  or  posterior , the  smaller,  termed  the  hyo- 
pharyngeus  muscle,  comes  from  the  posterior  part  of  the  upper  edge  of 
the  great  horn  of  the  hyoid  bone. 

The  upper  or  anterior , which  is  the  larger  and  is  termed  the  glosso- 
chondro-pharyngeus  muscle,  arises  from  the  small  horn  of  the  hyoid 
bone  and  from  the  base  of  the  tongue. 

Its  lower  fibres  are  transverse  and  even  convex  downward  ; the 
upper  are  very  oblique  and  are  generally  pointed,  and  either  alone  or 
blended  with  the  upper  fibres  of  the  constrictor  pharyngis  inferior  mus- 
cle, extends  as  the  cephalo-phamyngeus  muscle  ; to  the  basilar  process 
of  the  basilar  bone,  and  is  attached  to  its  lower  face  by  fleshy  or  tendi- 
nous extremities. 

C.  CONSTRICTOR  PHARYNGIS  SUPERIOR. 

§ 2135.  The  constrictor  j)haryngis  superior  or  the  glosso-mylo- 
pterygo-pharyngeus  muscle  arises  from  the  posterior  part  and  the  side 
of  -the  root  of  the  tongue,  from  the  inner  face  of  the  lower  maxillary 
bone,  near  the  posterior  molar  tooth,  from  the  hook  of  the  pterygoid 
process,  and  from  the  tendon  of  the  peristaphylinus  externus  muscle, 
often  also  a little  from  the  petrous  portion  of  the  temporal  bone  and 
from  the  styloid  process,  and  blends  with  the  posterior  part  of  the 
genio-glossus  and  buccinator  muscles,  and  often  also  with  the  lower 
portion  of  the  stylo-pharyngeus  muscle. 

Its  lower  fibres  are  transverse  ; the  upper  describe  an  arch  which  is 
convex  upward. 

D.  STYLO-PHARYNGEUS. 

§ 2136.  The  stylo-pharyngeus  muscle  (M.  stylo-phanjngeus , s.  le- 
vator, s.  dilator  pharyngis)  is  large,  elongated,  and  rounded.  It  arises 
by  a broad  and  short  tendon  from  the  inner  face  and  the  lower  edge  of 
the  styloid  process  of  the  temporal  bone.  Thence  it  goes  inward  and 
downward.  It  is  at  first  separated  from  the  constrictor  pharyngis  su- 
perior muscle  by  a greater  or  less  quantity  of  fat  ; it  goes  from  above 
downward  and  from  without  inward,  passes  under  the  lateral  part  of 


250 


DESCRIPTIVE  ANATOMY. 


the  constrictor  médius  muscle,  and  is  distributed  on  the  lateral  and 
posterior  wall  of  the  constrictor  médius,  and  adheres  to  its  vascular 
tunic  very  intimately  by  a dense  cellular  tissue. 

Its  upper  fibres  curve  in  an  arch  from  below  upward  and  interlace 
with  those  of  the  superior  constrictor.  The  inferior  separate  like  a 
pair  of  forceps.  Both  descend  to  the  base  of  the  upper  horn  of  the 
thyroid  cartilage,  and  are  attached  to  its  posterior  edge. 

This  muscle  raises  the  pharynx  and  the  larynx,  and  dilates  the  first 
of  these  two  cavities  transversely. 

§ 2137.  The  vascular  tunic  of  the  pharynx  which  is  considerably 
thick  comes  next  to  the  muscular  portion. 

The  inner  tunic  or  the  mucous  membrane  is  very  thin,  smooth,  and 
reddish  white.  It  is  uninterruptedly  continuous  above  with  that  of  the 
mouth  and  nose,  below  with  that  of  the  esophagus. 

II.  ESOPHAGUS. 

§ 2138.  The  esophagus^  1)  is  that  part  of  the  alimentary  canal  in- 
cluded between  the  pharynx  and  the  stomach.  It  is  narrower 'than 
either,  and  is  continuous  with  them  at  its  two  extremities  by  tunnel- 
like portions. 

This  canal  is  situated  in  the  posterior  mediastinum,  and  extends  its 
whole  length  before  the  vertebral  column.  Its  upper  part  corresponds 
directly  to  the  anterior  face  of  the  spine  from  the  fifth  cervical  vertebra 
and  the  cricoid  cartilage,  where  it  commences,  to  the  fifth  dorsal  ver- 
tebra, although  it  frequently  also  inclines  a little  to  the  left.  From  this 
point  to  the  ninth  dorsal  vertebra  it  inclines  slightly  to  the  right  ; it 
then  returns  on  the  anterior  face  of  the  column,  passes  through  the 
esophageal  fissure  of  the  diaphragm,  and  soon  terminates  at  the  upper 
or  left  orifice  of  the  stomach. 

At  its  upper  part  it  is  situated  behind  the  trachea.  From  the  fifth 
dorsal  vertebra  it  is  found  between  the  aorta  on  the  left  and  the  azygos 
vein  on  the  right  side.  It  is  united  to  the  adjacent  parts  by  a very 
loose  cellular  tissue. 

§ 2139.  The  esophagus  is  the  narrowest  part  of  the  alimentary 
canal.  Even  in  its  greatest  dilatation  its  diameter  is  not  an  inch.  It 
is  equally  broad  in  every  part,  except  at  most  the  slightly  contracted 
portion  which  passes  through  the  diaphragm. 

The  muscular  tunic  is  considerably  thick  ; it  is  generally  at  least 
a line  in  thickness. 

It  is  composed  of  two  layers,  one  external  longitudinal,  the  other 
internal  transverse,  the  first  of  which  is  twice  as  thick  as  the  second. 
The  longitudinal  fibres  usually  commence  above  by  three  fasciculi  or 

(1)  J.  Bleuland,  Observations  anatomico-mcdicœ  de  sana  et  morbosa  oesophagi 
structura,  Leyden,  1785.— V.  Malacarne,  Suit'  esafago , suite  intestine,  c sopra  alcune 
valvulo  del  tubo  alimentare,  Padua,  1803. 


OP  THE  DIGESTIVE  SYSTEM. 


251 


heads,  a middle  and  two  lateral.  The  middle  head  arises  by  a tendon 
from  the  centre  of  the  posterior  face  of  the  cricoid  cartilage  directly 
below  its  upper  edge,  and  expands  a little  in  descending.  The  two 
lateral  heads,  which  are  fleshy,  descend  from  the  lower  edge  of  the 
constrictor  pharyngis  inferior  muscle.  These  three  fasciculi  unite 
some  inches  below  the  upper  extremity  to  form  a muscular  membrane 
which  is  uniformly  extended. 

The  circular  fibres  are  a continuation  of  the  inner  posterior  part  of 
the  constrictor  pharyngis  inferior  muscle,  but  are  much  thinner  than 
those  of  this  muscle. 

The  upper  are  transverse  ; the  next  are  oblique  from  above  down- 
ward and  from  without  inward,  intercross  with  those  of  the  opposite 
side,  and  describe  spiral  lines  ; the  inferior,  like  the  superior,  form 
straight  rings.  This  canal  for  about  an  inch  at  the  upper ^end  of  the 
esophagus  presents  no  circular  fibres  on  its  anterior  face,  and  as  the 
longitudinal  fasciculi  are  not  united  in  this  place,  the  esophagus  is 
here  much  less  muscular  and  more  extensible  than  in  other  parts. 

The  cellular  or  vascular  tunic  comes  next  to  the  muscular,  and  is 
attached  to  it  very  loosely,  while  it  adheres  strongly  to  the  internal 
membrane  with  which  it  forms  an  internal  canal  which  is  easily  de- 
tached from  the  muscular  membrane. 

In  this  tunic  there  are  numerous  muciparous  glands  arranged  very 
compactly  and  composed  of  smaller  granulations,  which  diminish  in 
number  and  size  as  they  approach  the  lower  extremity. 

The  inner  or  villous  tunic  is  whitish,  solid,  and  presents,  on  its  inner 
face,  numerous  and  very  narrow  longitudinal  grooves  separated  by 
parietes.  We  ought  not  to  consider  it  as  the  same  with  the  pre- 
ceding^].) 

Its  inner  face  is  covered  with  a thinner,  more  delicate,  and  moist  mem- 
brane, which  is  evidently  an  epidermis,  and  which  suddenly  terminates 
at  the  lower  part  of  the  esophagus  at  the  part  where  it  is  continuous 
with  the  stomach.  The  folds  of  this  epidermis  are  easily  separated  by 
boiling  and  maceration,  although  it  is  difficult  to  detach  it  entire  unless 
it  is  morbidly  thicker  and  firmer  from  some  pathological  change. 
Farther  the  lower  extremity  of  the  esophagus  is  detached  from  above 
downward  in  one  or  more  parts  sometime  after  death,  which  undoubt- 
edly arises  from  the  fact  that  the  fluid  secreted  by  the  glands  of  the 
esophagus  and  cardiac  portion  of  the  stpmach  soften  and  dissolve  it, 
and  also  the  loose  cellular  tissue  which  unites  it  to  the  cellular  tunic. 


(1)  Scemmerring  ( Eingeweidelehre , p.  216)  describes  these  two  tunics  as  forming 
but  one,  termed  the  vascular  or  internal  glandular  tunic  ; he  says  that  the  inner 
membrane  and  the  vascular  membrane  of  the  stomach  are  continuous  with  it.  It  is 
true  that  the  internal  membrane  of  the  stomach  is  continuous  with  that  of  the 
esophagus,  and  its  vascular  membrane  with  that  of  this  canal.  Other  anatomists 
err  still"  more  in  considering  the  villous  tunic  of  the  stomach  and  intestinal  canal  as 
a continuation  of  the  epidermis  of  the  esophagus. 


252 


DESCRIPTIVE  ANATOMV. 


§ 2140.  After  the  food  is  masticated  by  the  teeth  in  the  cavity  of 
the  mouth,  mixed  with  the  saliva  and  formed  into  a soft  mass,  the 
muscles  of  the  tongue,  the  hyoid  bone,  the  pharynx,  and  the  esophagus 
propel  it  successively  toward  the  stomach  ; this  constitutes  deglutition 
(deglutitio).(  1)  In  order  to  this,  the  mass  of  food  is  moved  from  before 
backward  in  the  cavity  of  the  mouth,  which  motion  requires  the  close 
of  this  cavity  by  approximating  the  jaws  and  lips.  At  the  same  time, 
the  tongue  is  moved  by  its  muscles,  so  that  its  edges  are  raised  and  its 
centre  is  depressed,  and  it  thus  forms  a kind  of  groove,  which  touching 
the  palate  makes  a canal,  in  which  the  food  proceeds  from  before  back- 
ward, because  there  is  the  least  resistance  in  this  direction.  When  it 
has  passed  through  this  course,  the  genio-glossi  and  genio-hyoidei 
muscles,  which  restore  the  tongue  to  its  position  and  carry  it  forward 
also  favor ^its  progress,  because  they  thus  raise  the  soft  palate,  to  which 
motiottals'o  the  levator  muscles  of  this  latter  contribute.  When  the 
food  has  arrived  at  this  place  the  constrictor  muscles  of  the  pharynx 
contract  ; at  the  same  time  the  depressors  of  the  soft  palate  and  the 
stylo-glossi  muscles  act  to  raise  the  tongue  and  contract  the  isthmus 
of  the  fauces  ; the  contractions  of  the  constrictor  phauyngis  superior 
muscle  press  the  pharynx  against  the  soft  palate,  and  thus  close  the 
nasal  fossæ  as  they  had  been  before  by  raising  the  soft  palate.  The 
stylo-pharjmgei  muscles,  then  the  constrictors  of  the  isthmus  of  the 
fauces,  raise  and  dilate  the  pharynx,  so  that  the  food  can  enter  there 
more  easily. 

The  genio-hyoidei,  the  mylo-hyoidei,  the  thyro-hyoidei  and  the  hyo- 
glossi  muscles  carry  the  larynx  forward  and  upward  ; this  motion 
favors  the  closing  of  the  glottis  by  the  epiglottis,  which  the  pressure  of 
the  food  also  serves  to  depress,  so  that  nothing  can  enter  the  air  pas- 
sages. 

All  these  parts  being  extremely  irritable  act  very  rapidly  and  easily. 
Deglutition,  which  is  at  first  voluntary,  becomes  involuntary  in  the  eso- 
phagus, although  this  passage  receives  its  nerves  from  the  pneumo- 
gastric  nerves. 


B.  ABNORMAL  STATE. 

I.  DEVIATIONS  OF  FORMATION. 

§ 2141.  1st.  Primitive  deviations.  Sometimes  but  rarely  the  pha- 
rynx and  the  esophagus  terminate  in  a cul-de-sac,  one  at  its  lower  the 
other  at  its  upper  part,  from  a primitive  deviation  of  formation.  In  the 

(1)  Schulze,  De  deglutitionis  mechanismo,  Halle,  1739. — F.  B.  Albinus,  De  dcglu- 
titione,  Leyden,  1740. — Wentz,  De  deglutitionis  mechanismo,  Erlangen,  1780. — P.  J. 
Sandifort,  Deglutitionis  mcckanismus,  vcrlicall  seclionc  narium , oristfaucium  illus- 
tratus , Leyden,  1805. 


OF  THE  DIGESTIVE  SYSTEM. 


253 


first  place  the  cavity  of  the  mouth  also  is  generally  at  least  imper- 
fectly developed,  and  the  lower  jaw  is  wholly  or  in  great  part  deficient. 
The  same  thing  occurs  when  the  pharynx  opens  in  the  neck  by  a very 
narrow  orifice. 

Another  primitive  deviation  of  formation  which  is  more  rare,  is  the 
division  of  a part  of  the  esophagus  into  two  passages  situated  at  the 
side  of  each  other.(l) 

We  cannot  always  determine  if  the  contractions  of  the  esophagus, 
which  depend  on  the  abnormal  folding  of  the  inner  membrane  without 
any  morbid  change,  are  primitive  deviations  of  formation,  or  are  pro- 
duced consecutively  by  a simple  increase  of  this  membrane. 

We  must  however  admit  that  this  latter  sometimes  occurs,  since 
accidents  frequently  appear  only  a little  while  before  death. 

2d.  Accidental  deviations  of  formation.  Dilatations  of  the  esopha- 
gus are  generally  accidental..  They  usually  occur  after  contractions 
situated  below  them,  and  in  this  case  they  are  general. 

More  unfrequently  a portion  of  the  circumference  of  the  canal 
appears  dilated  in  a cul-de-sac. (2)  In  one  case  the  pouch  was  cer- 
tainly caused  by  a hernia  of  the  internal  membrane  through  the 
muscular  tunic, (3)  while  in  another  this  latter  also  contributed  to 
it.  (4) 

Pouches  of  this  kind  occur  only  at  the  lower  extremity  of  the  pharynx 
or  at  the  commencement  of  the  esophagus,  doubtless  on  account  of  the 
sudden  contraction  of  the  alimentary  canal  in  this  place,  and  because 
the  esophagus  is  less  muscular  there  than  in  other  parts. 

Ruptures  of  the  esophagus  which  are  sometimes  transverse(5)  and 
sometimes  longitudinal, (6)  are  only  a greater  degree  of  the  hernia 
of  the  inner  membrane.  They  are  sometimes  caused  by  abnormal 
brittleness. 

When  the  contractions  are  permanent,  they  generally  supervene 
after  a morbid  alteration  of  texture,  as  thickening  and  induration  of  the 
coats  of  the  esophagus,  so  that  they  are  rarely  pure  deviations  of  forma- 
tion. Sometimes,  however,  they  depend  originally  on  a simple  abnor- 
mal contraction  of  the  muscular  fibres,  which  continues  even  after 
death  ; and  the  greater  hardness  in  this  part  does  not  result  from  an 
alteration  of  texture,  but  only  from  a stronger  contraction  of  the  mus- 
cular tunic,  although  the  continual  pressure  of  the  latter  on  the  inner 
membrane  may  also  change  its  texture,  and  excite  in  it  inflammation, 


(1)  Blaes,  Obs.  medicos  rariores,  tab.  vi.,  fig.  2. 

(2)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  ii.— Bell,  Surgical  obser- 
vations, pt.  i.,  London,  1817,  p.  167,  tab.  ii. 

(3)  Bell,  loc.  cit. 

(4)  Ludlow,  Med.  obs.  andinq.,  vol.  iii. 

(5)  Boerhaave,  His.  morbi  atrocis,  Leyden,  1724. 

(6)  Monro,  Morbid  anatomy,  p.  311. 


VOL.  III. 


33 


254 


DESCRIPTIVE  ANATOMY. 


followed  by  effusion  and  suppuration,  which  render  the  induration 
permanent.(l) 

II.  ALTERATIONS  OF  TEXTURE. 

§ 2142.  The  most  common  alteration  in  the  texture  of  the  esopha- 
gus, is  an  abnormal  hardness,  usually  attended  with  thickening,  and 
consequently  with  a greater  or  less  contraction,  or  even  with  a total 
closing  of  it, (2)  which  state  is  termed  a scirrhus,  and  in  which  the  dif- 
ferent tunics  of  the  passage  are  more  or  less  blended  in  a mass,  some- 
times homogeneous  and  cartilaginous,  sometimes  divided  into  several 
compartments  by  tendinous  septa.  Commonly  then  the  texture  of  the 
inner  face  is  altered.  This  alteration  is  not  observed  in  all  parts  indis- 
criminately; it  is  more  frequent  at  the  upper  and  lower  extremities  of 
the  esophagus,  in  the  former  place,  on  account  of  the  sudden  contrac- 
tion of  the  pharynx  ; in  the  latter,  because  the  lower  portion  of  the  eso- 
phagus tends  to  contract,  since  the  two  orifices  of  the  stomach  are  per- 
fectly closed  during  digestion,  so  that  it  is  very  easily  injured  by  sub- 
stances passing  through  it. 

Abnormal  communications  between  the  esophagus  and  the  adjacent 
parts,  particularly  the  trachea, (3)  the  lungs, (4)  the  aorta, (5)  may  oc- 
cur from  cancer  or  common  ulcerations.  This  state  may  also  be  oc- 
casioned by  ulcers  formed  primitively  in  the  aorta. (6) 

We  can  sometimes,  but  not  always,  determine  from  the  state  of  the 
parts,  which  was  the  primitive  disease. 

Beside  the  alterations  of  texture  in  the  membranes  mentioned,  ex- 
crescences, funguses,  and  polypi  of  different  kinds,  are  sometimes,  al- 
though rarely,  developed  in  the  pharynx  and  the  esophagus  ; these 
arise  from  the  inner  face  of  this  canal, (7)  and  usually  have  their  roots 
in  the  mucous  and  vascular  membranes.  They  are  sometimes  so  long, 
that  commencing  near  the  upper  extremity  of  the  esophagus,  they  de- 
scend to  the  stomach.  They  are  sometimes  formed  by  fibres  perpen- 
dicular to  their  base, (8)  are  sometimes  lobed(9)  and  suppurate.(lO) 

Real  ossifications  are  still  more  rare.(ll) 

(1)  Baillie  relates  several  instances  of  it  : we  also  have  seen  it,  and  like  Baillie  in 
the  cadavers  of  females.  Mauchart,  De  struma  oesophagi  ejusque  coalitu,  Tubingen, 
1742. 

(2)  Gyser,  De  callosa  œsop hag i anguslia,  Strasburg,  1770.— J.  Bleuland,  De  dif- 
ficiliaut  impeditu  alimentorum  depulsione,  Leyden,  1780. 

(3)  VanDoever’en,  Obs.  anat.pathol.  Leyden,  1789,  obs.  ii. 

(4)  Bleuland,  loc.cit.,  obs.  i.  p.  48.  fig.  112. 

(5)  Van  Dceveren,  loc.  cit.,  obs.  i. 

(6)  We  have  one  very  remarkable  case  before  us. 

(7)  Monro,  loc.  cit.,  p.  184-189. — Baillie. 

(8)  Baillie,  loc.  cit. 

(9)  Monro,  loc.  cit.,  p.  188. 

(101  Baillie,  loc.  cit. 

(11)  Meckel,  Handbuch  der  pathologischen  Anatomic,  vol.  ii.  p.  2.  p.  227. 


OF  THE  DIGESTIVE  SYSTEM. 


255 


ARTICLE  SECOND. 

MIDDLE  AND  INFERIOR  PORTION  OF  THE  ALIMENTARY  CANAL. 

§ 2143.  The  middle  region  of  the  digestive  system  comprehends 
th ejtomacli  and  the  small  intestine , and  the  most  important  glandular 
organs  of  this  system,  the  liver,  the  spleen,  and  the  pancreas.  This  is 
the  largest  and  the  most  important  portion,  because  digestion  takes 
place  in  it,  for  which  the  preceding  portion  only  prepares,  while  the 
terminating  portion  serves  for  the  expulsion  of  the  residue. 

The  stomach,  the  liver,  the  spleen,  and  the  pancreas,  with  the  com- 
mencement of  the  small  intestine,  the  duodenum,  into  which  the  pan- 
creas, the  liver,  and  the  stomach  open,  occupy  the  upper  part  of  the 
abdominal  cavity.  They  are  separated  from  the  lower,  which  is  larger, 
by  a large  transverse  fold  of  the  peritoneum,  the  transverse  meso-colon. 
It  is  not,  however,  necessary  to  describe  the  lower  portion  of  the  intes- 
tine after  these  glands,  nor  to  separate  the.  large  intestine  from  the 
small,  since  they  are  both  situated  in  the  same  cavity,  then  texture  is 
essentially  the  same,  and  they  are  uninterruptedly  continuous  with 
each  other. 

It  is  customary  to  describe  the  peritoneum  before  mentioning  the 
parts  of  the  digestive  system  it  envelops  ; but  as  these  are  not  the  only 
parts  covered  by  it,  the  prolongations  which  extend  from  its  outer  sac 
to  the  organs  covered  by  it,  cannot  be  clearly  described  until  the  situa- 
tion and  form  of  these  organs  are  well  known  : finally,  the  important 
anomalies  of  this  membrane,  especially  those  which  occur  in  hernias, 
being  dependent  on  those,  to  which  several  of  the  parts  it  envelops  are 
subject,  it  is  better  to  defer  the  description  of  the  peritoneum  until  we 
mention  the  different  systems  it  supports.  This  is  the  method  followed 
by  Roux  in  the  Anatomie  descriptive  of  Bichat. 

We  shall  not  describe  on  this  occasion  the  cavity  of  the  abdomen, 
the  most  general  characters  of  which  have  been  already  mentioned. 

A.  PERFECT  STATE. 

§ 2144.  The  different  regions  of  the  middle  portion  of  the  alimentary 
canal,  doubtless  differ  very  much  in  respect  to  their  capacity  ; but  they 
are  very  analogous  in  regard  to  texture,  in  which,  however,  they  differ 
on  the  contrary,  from  the  upper  and  lower  portions.  The  longitudinal 
fibres  of  the  muscular  tunic  completely  surround  this  portion  of  the 
canal  ; the  vessels  which  go  to  it  are  more  numerous,  and  anastomose 
together  more  frequently,  and  finally,  the  inner  surface  of  the  mem- 
brane is  more  or  less  uneven,  from  prominences  which  do  not  exist  in 
the  other  two  portions. 


256 


DESCRIPTIVE  ANATOMY. 


I.  STOMACH. 

§ 2145.  The  stomach  ( ventriculus , stomachus)  ,{\)  the  broadest  part 
of  the  alimentary  canal,  is  included  between  the  esophagus  and  the 
duodenum.  The  portion  of  this  canal  in  the  cavity  of  the  abdomen 
commences  with  it.  The  alimentary  substances  all  fall  directly  within 
it,  assimilation  there  commences,  and  they  are  there  changed  into  a 
liquid  of  a peculiar  character  called  chyme  ( chymus ). 

A.  SITUATION. 

§ 2146.  The  stomach  is  situated  at  the  upper  part  of  the  abdominal 
cavity,  under  the  left  false  ribs.  Sometimes,  when  it  is  much  larger, 
it  descends  into  the  umbilical  region.  Its  direction  is  oblique  from  above 
downward  and  from  left  to  right.  Its  upper  extremity  touches  the 
diaphragm  ; the  lower  extends  to  near  the  lower  edge  of  the  left  or 
square  lobe  of  the  liver. 

§ 2147.  The  spleen  is  situated  near  its  left  extremity  ; behind  its 
posterior  face  is  the  pancreas,  below  it  the  transverse  colon,  above  it 
the  left  or  square  lobe  of  the  liver  and  the  lobe  of  Spigel,  which  is  em- 
braced by  its  upper  curve. 


B.  FORM. 

§ 2148.  The  stomach  has  the  form  of  an  elongated  cone,  a little 
curved  on  itself,  and  is  somewhat  similar  to  a bagpipe.  Its  right  ex- 
tremity is  the  narrowest,  and  its  left  the  broadest  portion. 

We  distinguish  in  it  two  orifiçes,  two  curves,  and  two  culs-de-sac. 

The  upper  or  left  orifice,  termed  also  the  cardiac  ( ostium  ventriculi 
sinislrum,  s.  superius , s.  cardia ),  occupies  the  highest  part  of  the 
stomach  near  its  left  cul-de-sac.  It  serves  as  the  limit  between  this 
viscus  and  the  esophagus,  which,  however,  are  continuous  with  each 
other  and  separated  by  no  prominence,  so  that  the  lower  extremity  of 
the  esophagus  gradually  enlarges. 

The  inferior  or  right  orifice,  termed  also  the  pijlorus  ( ostium  ventri- 
culi dextrum , s.  inferius , s.  pylorus,  s.  janitor, )( 2)  is  the  limit  between 
the  stomach  and  the  duodenum.  Here  the  transition  is  not  gradual 
and  imperceptible  as  on  the  left  side,  but  occurs  by  a prominence,  termed 
the  valve  of  the  pylorus  ( valvula  pylori). 

The  faces  and  the  curves  of  the  stomach  are  included  between  these 
two  orifices. 

(1)  Beside,  tho  works  of  Fabricius,  of  Aquapcndente,  Glisson,  and  Fantoni,  already 
cited,  consult  also  J.  D.  Metzger,  Ventriculus  humanus  anatomice  et  physiologies 
consideratus , Königsberg,  1788. 

(2)  Leveling,  Pylorus  anatomice  atquc physiologies  consideratus,  Strasburg,  1764. 


OF  THE  DIGESTIVE  SYSTEM. 


257 


The  posterior  and  the  anterior  faces,  when  the  stomach  is  more 
or  less  distended,  are  uniformly  convex,  but  wheq  the  stomach  is 
empty  they  are  straight,  flat,  and  in  contact. 

The  upper  or  small  curve , the  diaphragmatic  edge,  is  situated  be- 
tween the  right  side  of  the  upper,  and  the  left  side  of  the  lower  orifice; 
it  is  concave  and  much  smaller  than  the  lower,  which  is  also  called 
the  great  curve , the  colic  edge. 

When  the  stomach  is  empty,  the  two  curves  appear  as  more  or  less 
distinct  edges,  which  establish  a well  marked  separation  between  the 
two  faces.  But  when  the  viscus  is  full,  they  are  very  rounded,  and 
insensibly  continuous  with  the  two  faces. 

The  base,  tubercle,  or  great  cul-de-sac  of  the  stomach,  the  splenic  ex- 
tremity ( fundus , s.  saccus  cœcus),  is  a prolongation  in  the  form  of  a cul- 
de-sac  which  extends  from  right  to  left  on  leaving  the  left  side  of  the 
upper  orifice,  and  which  proceeds  about  three  inches  beyond  the  inser- 
tion of  the  esophagus. 

This  portion  of  the  stomach  is  not  much  narrower  than  its  centre. 
On  leaving  it  and  the  caidiac  orifice,  the  viscus  slightly  enlarges  to  a 
little  beyond  its  centre  from  left  to  right.  From  tips  latter  point  to  the 
pylorus,  it  gradually  contracts  very  much. 

When  one  or  two  inches  from  the  pylorus,  the  great  curve  suddenly 
inclines  inward,  but  immediately  resumes  its  former  direction,  although 
it  does  not  afterward  describe  so  great  a curve  as  in  the  rest  of  its 
course.  Hence,  there  is  a fissure,  opposite  which  the  right  portion  of 
the  small  curve,  instead  of  preserving  the  concave  form  which  it  pos- 
sessed from  the  cardiac  orifice,  becomes  convex  outward,  although  in 
this  place  there  is  no  contraction,  between  which  and  the  pylorus  is  a 
dilatation. 

The  portion  of  the  stomach  farthest  from  the  right  side,  is  termed  the 
antrum  of  the  pylorus,  or  the  small  cul-de-sac  ( antrum  pylori). 

C.  DIMENSIONS. 

§ 2149.  The  size  of  the  stomach  varies  much  in  the  same  indivi- 
duals, in  the  state  of  health  at  different  periods  ; as  this  viscus  dilates 
considerably  when  filled  with  food,  and  contracts  when  empty.  Its 
capacity  is  diminished  particularly  in  the  transverse  direction,  and 
often  to  such  an  extent  that  the  stomach  is  smaller  than  the  large  in- 
testine is  when  in  its  usual  and  moderate  state  of  distention. 

Generally,  when  the  stomach  is  not  unusually  full,  it  is  one  foot 
long  from  the  base  to  the  pylorus,  three  or  four  inches  high  in  it  high- 
est part,  and  about  as  many  broad  from  before  backward.  Its  surface 
is  about  one  square  foot  in  extent.  . 

D.  ATTACHMENTS. 

§2150.  The  stomach  is  attached  on  each  side  at  its  upper  orifice 
by  a short  fold  of  peritoneum,  termed  the  phreno-gasiric  ligament  ( JL . 


258 


DESCRIPTIVE  ANATOMY. 


phrenico-gastrictm),  which  extends  on  the  left  to  the  commencement 
of  the  hase,  and  descends  on  the  right  along  most  of  the  small  curve. 
This  ligament  is  attached  forward  and  upward  to  the  superior  lumbar 
portion  of  the  diaphragm. 

To  this  ligament  is  attached  another  which  is  much  longer,  the 
gastro-splenic  ligament  ( L . gastro-splenicum),  which  extends  from  the 
base  of  the  stomach  to  the  fissure  of  the  spleen,  where  it  is  attached, 
and  which  is  continuous  below  with  the  great  epiploon. 

The  stomach  is  united  to  the  transverse  colon  bj  the  great  epiploon, 
and  to  the  liver  by  the  small  epiploon,  internal  prolongations  of  the 
peritoneum,  which  we  shall  describe  after  giving  the  history  of  this 
membrane. 

E.  MEMBRANES. 

§ 2151.  The  stomach  is  enveloped  by  the  peritoneum  in  every  part, 
excepting  a narrow  ring  which  exists  along  the  great  and  small  curve, 
and  along  which  the  blood-vessels  proceed. 

Below  this  peritoneal  coat,  directly  on  its  inner  face,  is  the  muscular 
membrane, (1)  which  is  very  strong,  but  stronger  than  in  the  great  and 
the  small  intestine,  although  weaker  than  in  the  pharynx  and  rectum. 
It  is  about  half  a line  thick,  and  its  texture  is  more  complex  than  in  the 
rest  of  the  alimentary  canal,  and  we  may,  at  least  in  some  parts,  de- 
monstrate three  layers. 

The  external  layer  is  formed  of  longitudinal  fibres,  which  mostly 
blend  with  those  of  the  esophagus  and  duodenum,  and  are  uninter- 
ruptedly continuous  with  them.  These  fibres  are  very  much  developed 
at  the  upper  part  of  the  stomach,  around  its  small  curve  ; they  how- 
ever cover  all  its  surface. 

The  middle  layer  is  formed  by  annular  fibres,  representing  rings,  the 
centre  of  which  correspond  to  the  longitudinal  axis  of  the  stomach. 
They  commence  at  the  base  of  the  stomach,  and  interlace  with  each 
other,  proceed  a little  obliquely,  and  cover  the  whole  stomach  to  the 
pylorus,  where  they  are  strongest. 

They  are  termed  transverse  or  oblique  fibres.  They  form  the  thick- 
est layer. 

Below  this  layer  there  is  a third, (2)  which  is  very  evident  on  the 
left  side,  and  on  the  small  curve,  and  which  also  surrounds  the  stomach 
circularly,  but  in  an  opposite  direction  from  the  preceding,  that  is,  lon- 
gitudinally. They  are  the  continuation  of  the  circular  fibres  of  the 
esophagus,  and  frequently  interlace  with  the  oblique  fibres. 

The  vascular  membrane  of  the  stomach  is  thicker,  more  vascular, 
and  more  distinct  from  the  internal  membrane  than  in  the  esophagus. 


(1)  D.  G.  Galeati,  De  cornea  ventriculi  et  intestinorum  tunica;  in  Comm.  Bonort., 
1745. — Bcrtin,  Descr  iption  des  plans  vmsuleux  dont  la  tunique  charnue  de  l'estomac 
humain  est  composée , vol.  ii.  p.  235. 

(2)  Galeati  (lor.  cit.,  p.240)  described  this  membrane  long  before  Bertin. 


OF  THE  DIGESTIVE  SYSTEM. 


259 


It  is  uninterruptedly  continuous  with  the  vascular  tunic  of  this  canal, 
but  not  with  the  inner  or  villous  membrane. 

The  villous  membrane  of  the  stomach  is  thin,  soft,  loose,  and  spungy, 
softer  and  looser,  but  a little  thicker  than  the  corresponding  membrane 
of  the  esophagus.  It  usually  assumes,  soon  after  death,  a yellowish, 
brownish,  or  reddish  tint.(l)  Not  unfrequently,  especially  when 
examined  shortly  after  'death,  it  presents  in  a greater  or  less  extent, 
especially  at  the  base  and  at  the  small  curve,  a very  red  color,  caused 
by  a network  of  small  vessels  almost  exclusively  veins.  We  generally 
consider  this  state  as  the  consequence  of  an  inflammation  which  had 
affected  the  organ  during  life  ; and  conclude  from  its  existence  that  the 
patient  had  been  poisoned.  But  attentive  examination  demonstrates 
that  it  supervenes  during  the  struggles  of  death,  without  any  sus- 
picions of  such  a cause,  and  is  occasioned  particularly  by  the  sudden 
suspension  of  the  circulation  in  the  lungs. (2) 

When  the  stomach  is  not  distended,  its  villous  membrane,  and  con- 
sequently its  inner  face,  present  numerous  large  and  small  wrinkles, 
which  are  arranged  very  irregularly.  But  these  wrinkles  disappear 
when  this  viscus  is  even  very  moderately  distended,  so  that  when  we 
look  at  the  membrane  with  the  naked  eye  its  inner  face  seems  smooth, 
although  when  examined  with  a microscope  this  same  face  seems 
divided  by  several  small  intermediate  parietes  ; which  enlarge  to- 
ward the  pylorus  and  by  this  are  still  more  similar  to  the  villosities  of 
the  intestines,  into  numerous  compartments  ; these  are  arranged  very 
compactly,  like  the  cells  in  a bee-hive. (3)  The  cellules  are  larger 
but  fewer  in  the  left  half  of  the  stomach,  and  are  separated  by  simple 
septa.  In  the  region  of  the  pylorus,  these  septa  present  numerous 
grooves  which  render  them  still  more  similar  to  the  villosities  of  the 
intestines,  although  they  are  much  smaller  in  other  respects  than  these 
latter.(4) 

Beside  numerous  slight  depressions,  which  are  the  orifices  of  small 
simple  glands,  the  inner  membrane  of  the  stomach  also  presents,  espe- 

(1)  The  French  physicians  having  studied  for  several  years  the  alterations  in  the 

mucous  membrane  of  the  digestive  canal,  they  have  naturally  considered  also  its 
normal  conditions.  Rousseau  (Des  différent  aspects  que  présente,  dans  l'état  sain,  la 
membrane  muqueuse  gastro-intestinale  ; in  the  Archiv,  gêner,  de  méd.,  vol.  vi.  p. 
321)  has  observed,  that  in  the  healthy  state  it  is  white  or  slightly  rosy  white.  This 
primitive  color  varies  in  different  parts  of  the  alimentary  canal.  Thus,  the  mucous 
membrane  of  the  pharynx  is  slightly  rosy  ; that  of  the  esophagus  is  white,  particu- 
larly at  its  lower  part  ; in  the  stomach  it  has  a slight  rosy  tint  as  in  the  pharynx. 
This  rosy  color  becomes  less  intense  in  its  pyloric  portion,  changes  to  white  in  the 
duodenum,  preserves  this  appearance  in  the  rest  of  the  small  intestine,  then  becomes 
of  a pale  white  in  the  cæcum,  the  colon,  the  commencement  of  the  rectum,  and  re- 
sumes its  slightly  reddish  color  near  the  end  of  this  last  intestine.  F.  T. 

(2)  J.  Yelloly,  On  the  vascular  appearance  of  the  human  stomach,  which  is  fre- 
quently mistaken  for  inflammation  of  that  organ  ; in  the  Med.  chir.  trans..  vol  iv 
1813,  p.  371-424. 

(3)  Hewson,  Experim.  inq.,  vol.  ii.,  p.  173. 

(4)  E.  Home  has  figured  this  (Observations  on  the  gastric  glands  of  the  human 
stomach  and  the  contraction  which  takes  place  in  that  viscus  ; in  the  Phil.  Irans 
1817,  pt.  i.,  p.  347,  pi.  i,  xviii,  xix. 


260 


DESCRIPTIVE  ANATOMY. 


cially  near  the  two  orifices,  others  which  are  larger  and  which  lead  to 
more  or  less  apparent  large  glands.  These  last  glands  form  at  the 
union  of  the  esophagus  and  stomach  a very  marked  prominence  from 
three  to  four  lines  broad,  which  separates  the  two  cavities  to  a certain 
extent. 

The  villous  membrane  of  the  stomach  is  uninterruptedly  continuous 
with  that  of  the  esophagus  and  intestinal  canal.  But  it  does  not  seem 
to  be  connected  with  the  epidermis  of  the  esophagus,  since  we  may 
without  the  least  violence  separate  this  epidermis  from  it  and  from  the 
villous  tunic  of  the  esophagus  around  the  cardiac  orifice. 

The  membranes  of  the  stomach  vary  in  thickness  in  different  indi- 
viduals, and  in  different  parts  of  this  viscus  of  the  same  individual,  and 
at  different  periods.(l) 

Generally,  in  the  first  respect,  they  are  thickest  in  those  male 
subjects  who  enjoy  good  health,  and  in  the  second  they  are  thicker,  as 
is  easily  imagined,  the  less  the  stomach  is  distended.  In  regard  to  the 
third  we  may  admit  that  the  peritoneal  coat  is  equally  thick  in  every 
part,  while  the  others  are  much  thinner  in  this  cul-de-sac  of  the 
stomach  than  in  the  other  parts  of  the  viscus,  and  are  thickest  near 
the  pylorus,  where  they  are  frequently  six  times  thicker  than  at  the 
base. 

F.  VALVE  OF  THE  PYLORUS. 

§ 2152.  The  valve  of  the  pylorus  ( valvula  pylori)  is  formed  by 
the  circular  fibres  of  the  muscular  tunic,  and  also  by  the  vascular  and 
mucous  tunics  of  the  stomach  and  duodenum.  The  first  two  mem- 
branes are  much  thicker  in  this  place,  and  all  three  are  reflected  on 
themselves  from  without  inward. 

The  longitudinal  fibres  in  the  peritoneal  coat  only  pass  on  this  point 
to  the  outside. 

It  is  very  easy  to  remove  the  valve  by  cutting  or  raising  the  longi- 
tudinal fibres.  But  there  is  always  a contraction  at  the  union  of  the 
stomach  with  the  duodenum. 

A peculiar  glandular  substance  has  been  mentioned  as  situated  be- 
tween the  muscular  and  peritoneal  tunics,  and  as  forming  the  pylorus 
and  determining  its  form-;(2)  but  with  the  utmost  care  in  our  dissec- 
tions we  have  never  been  able  to  discover  the  least  trace  of  this  sub- 
stance, although  we  always  find  a very  thick  glandular  layer  before 
the  pylorus,  below  the  muscular  membrane  of  the  duodenum. 

The  form  of  the  valve  varies. 

It  generally  circumscribes  the  whole  orifice  of  the  viscus,  and  it  is 
sometimes  circular  and  sometimes  more  or  less  oval  ; in  the  latter  case 
its  longitudinal  diameter  usually  extends  from  above  downward. 

(1)  Yelloly,  loc.  cit .,  p.  400,  402. 

(2)  Sœmmerriug,  Eingeweidelehrc,  p.  236.— Portal,  An.  méd.  vol.  v.,  p.  161. 


OF  THE  DIGESTIVE  SYSTEM. 


261 


It  is  more  unfrequently  semicircular,  surrounding  only  a part  of  the 
orifice. 

Between  this  formation  and  the  preceding  there  is  an  intermediate 
degree  in  which  the  valve  differs  considerably  in  its  breadth,  according 
to  the  different  parts  in  which  it  is  examined. 

It  is  sometimes  larger  and  sometimes  smaller. 

It  is  not  certain  that  we  ought  always  to  admit  that  it  possesses 
during  life  the  form  which  it  has  after  death. 

We  cannot  determine  precisely  what  effect  a given  form  of  the  valve 
has  even,  admitting  its  existence  and  permanence  during  life,  on  the 
action  of  the  valve  and  on  the  more  or  less  closing  of  the  pylorus  by 
it,  since  it  is  evident  that  the  degree  of  contractilitjr  in  the  circular 
fibres  which  contribute  principally  to  form  this  fold  has  still  more 
influence. 

C.  TRANSIENT  MODIFICATIONS  IN  THE  FORM  AND  SITUATION  OF  THE  STOMACH. 

§ 2153.  The  stomach  presents  regularly  transient  modifications  in 
its  situation,  according  as  it  does  or  does  not  contain  food.  These 
modifications  correspond  then  to  the  different  states  of  digestion. 

The  stomach  is  not  only  smaller  when  perfectly  empty  than  when 
it  contains  food,  but  then  its  form  is  not  cylindrical.  Its  anterior  and 
posterior  faces  touch  and  its  two  edges  are  distinct  from  each  other, 
while  when  full,  its  edges  and  faces  are  imperceptibly  continuous. 

A still  more  remarkable  modification  occurring  during  digestion,  is, 
that  the  stomach  is  then  divided  into  a right  and  a left  half  ; this  occurs 
about  its  centre,  and  is  more  or  less  distinct.  The  left  half  contains 
the  fluids  and  the  right  the  solid  substances,  and  the  former  pass  out 
from  them  into  the  small  intestine  without  proceeding  necessarily  or 
at  least  entirely  through  the  right  half  and  the  pylorus.(l) 

The  orifices  of  the  stomach  are  more  or  less  perfectly  closed  during 
digestion  ; when,  however,  this  process  has  continued  some  time  the 
pylorus  opens,  and  the  mass  contained  in  the  stomach  passes  through 
it  to  descend  into  the  duodenum,  in  proportion  as  it  is  digested. 

The  situation  of  the  stomach  also  changes  during  digestion;  it  turns 
on  its  axis,  so  that  its  anterior  face  looks  more  upward  and  the  poste- 
rior downward,  although  this  apparent  change  in  situation  depends 
principally  on  that  in  its  form  above  mentioned. 

H.  FUNCTION  OF  THE  STOMACH. 

§ 2154.  The  inner  membrane  of  the  stomach  secretes  the  gastric 
juice  ( succas  gastricus),  a fluid  the. exact  nature  of  which  it  is  difficult 
to  determine,  as  it  is  always  more  or  less  mixed  with  the  substances 

(1)  E.  Home,  Lectures  on  comparative  anatomy , vol.  i.,  p.  138. 

Vol.  III.  34 


262 


DESCRIPTIVE  ANATOMY. 


introduced  into  this  viscus.  It  generally  contains  an  uncomhined 
acid.(l) 

It  however  appears  to  be  sometimes  acid  and  sometimes  neutral  in 
the  same  subject.  Its  base  seems  to  be  an  albuminous  substance  very 
analogous  to  that  in  the  saliva. (2)  Perhaps  its  composition  is  not 
always  the  same,  and  varies  from  the  nature  of  the  substances  which 
act  on  the  inner  membrane  of  the  stomach.  The  action  of  this  fluid, 
united  perhaps  with  that  of  the  bile,  changes  the  food  into  a mucila- 
ginous, gray,  and  thick  pulp,  of  a disagreeable  odor  and  taste,  termed 
chyme  ( chymus ).  The  nature  of  this  pulp  varies  with  that  of  the  ali- 
mentary substances  ; it  includes  more  solid  parts  and  less  of  salts  than 
any  other  of  the  animal  fluids.  It  contains  much  carbon  and  albumen, 
but  no  gelatine,  at  least  if  we  may  judge  from  some  experiments.  It 
forms  gradually  in  the  pyloric  portion. (3) 

The  formation  of  chyme,  or  the  digestion  in  the  stomach , is  singu- 
larly favored  by  the  closing  of  its  two  orifices.  We  must  also  mention 
among  the  causes  which  favor  this  process  the  motions  of  the  sto- 
mach, which  are  at  first  vague  and  irregular,  but  which  gradually 
take  place  about  the  end  of  chymification  from  the  cardiac  to  the 
pyloric  orifice. 

I.  SEXUAL  DIFFERENCES, 

§2155.  The  stomach  is  the  only  portion  of  the  alimentary  canal 
which  presents  sexual  differences.  It  is  larger,  shorter,  and  broader 
in  the  male  ; smaller,  narrower,  and  longer  in  the  female^.  Its  mus- 
cular coat,  like  that  in  the  whole  alimentary  canal,  is  generally  also 
thinner  in  the  female.* 

II.  SMALL  INTESTINE. 

§ 2156.  The  small  intestine  ( intestinum  tenue, ){ 4)  the  narrowest  and 
thinnest  portion  of  the  intestinal  canal,  is  included  between  the  sto- 

(1)  This  opinion  has  at  least  •-'become  very  general  since  the  time  of  Spallanzani, 

although  the  experiments  of  Montègre  tend  to  prove  that  it  is  not  always  correct. 
Prout  asserts  that  the  free  or  at  least  the  unsaturated  acid  often  existing  in  the 
stomach  of  animals  is  the  hydrochloric,  and  that  the  salts  commonly  found  in  this 
viscus  are  the  alkaline  hydrochlorates  (Phil,  trans.,  1824,  p.  1);  : . Children  has  ar- 
rived at  the  same  result  by  analyzing  the  fluids  vomited  by  a man  during  a violent 
attack  of  dyspepsia  (Annals  of  philosophy,  1824,  July).  F.  T. 

(2)  Bostock,  in  the  Med.  chir.  trans.,  vol.  iv.,  p.  177. 

(3)  Marcet,  in  the  Med.  chir.  trans.,  vol.  vi.,  p.  627. — Prout,  Mémoire  sur  V héma- 
tose et  le  sang  en  général  ; in  the  Journ.  compl.  des  sc.  méd.,  vol.  xi.,  p.  132-215. 

* Beside  the  sexual  differences,  Dr.  S.  Th.  de  Sœmmerring  has  shown  that  the 
stomach  of  the  negro  differs  from  that  of  the  European,  in  being  of  a more  rounded 
form,  approaching  that  of  the  ape  (Am.  Med.  Journal,  Nov.,  1828). 

(4)  Helvetius,  Observations  sur  la  membrane  interne  des  intestins^  grêles,  appelée 
veloutée,  sur  leur  membrane  nerveuse,  et  sur  leur  membrane  musculeuse  ou  charnue  ; 
in  the  Mém.  de  Paris,  1721,  p.  392-403. — C.  B.  Albiuus,  Dcscriplio  inieslinormn 
tenuium  hominis , Leyden,  1722, 1724. 


OF  THE  DIGESTIVE  SYSTEM. 


263 


mach  and  the  large  intestine.  It  is  uninterruptedly  continuous  with 
both,  although  separated  by  two  valvular  folds,  the  pylorus  and  the 
ilieo-cœcal  valve,  the  closing  of  which  can  perfectly  insulate  its  cavity, 
which  is  sometimes  the  case. 

Its  outer  circumference  is  uniform  ; this  is  also  the  case  with  its 
diameter  in  most  of  its  extent,  and  hence  it  is  cylindrical. 

Its  whole  length  from  the  pylorus  to  the  commencement  of  the  colon 
varies  much  from  thirteen  to  twenty-seven  feet,  although  the  length 
of  the  body  does  not  differ  in  the  same  proportion. 

It  is  about  an  inch  in  diameter  when  moderately  distended. 

The  description  of  the  duodenum  may  be  separated  from  that  of  the 
small  intestine,  as  it  differs  from  this  latter  in  several  respects. 

A.  DUODENUM. 

§ 2157.  The  commencement  of  the  small  intestine,  that  portion 
directly  next  to  the  stomach,  is  called  the  duodenum  from  its  length. (1) 

This  intestine  is  situated  in  the  right  half  of  the  abdomen.  It  de- 
scribes a considerable  arch,  the  convexity  of  which  looks  to  the  right 
and  the  concavity  to  the  left.  We  distinguish  in  it  three  parts,  a su- 
perior , which  ascends  obliquely  from  left  to  right  and  a little  from 
before  backward;  a middle,  oblique  from  right  to  left  and  descending; 
finally  an  inferior,  dfjique  from  right  to  left  and  ascending. 

It  is  attached  to  the  gall-bladder  and  lo  the  commencement  of  the 
transverse  colon.  Its  upper  and  smallest  portion  is  situated  above, 
and  the  lower  and  largest,  below  the  transverse  colon.  It  is  covered 
in  most  of  its  anterior  face  by  the  posterior  wall  of  the  peritoneum, 
which  extends  forward  in  this  place  to  form  the  transverse  mesocolon, 
surrounds  it  loosely,  and  keeps  it  fixed  against  the  posterior  wall  of 
the  abdominal  cavity. 

The  middle  portion  descends  below  the  transverse  mesocolon,  and 
when  this  fold  of  the  peritoneum  is  raised  it  is  seen  on  the  right  side  of 
the  mesentery. 

The  third,  on  the  contrary,  is  situated  on  the  left  side  of  the  mesen- 
tery, the  upper  part  of  which  arises  from  it  directly.  It  extends  to  the 
second  lumbar  vertebra,  goes  forward  in  the  place  where  the  upper 
extremity  of  the  mesentery  blends  with  the  transverse  mesocolon  and 
opens  into  the  jejunum. 

If  we  except  its  first  portion,  which  is  covered  in  every  part  by  the 
peritoneum,  the  duodenum  is  protected  by  this  membrane  only  on  its 
anterior  side  ; the  posterior  is  attached  by  a very  loose  cellular  tissue 
to  the  posterior  wall  of  the  abdomen  and  directly  to  the  organs  situated 
behind  it. 

(1)  L.  Claussen,  De  intestini  duodeni  situ  ct  ne.ru,  Leipsie,  1757. — Sand^rt,  Ta- 
bula inteslini  duodeni , Leyden,  1780. 


264 


DESCRIPTIVE  ANATOMY. 


The  middle  portion  descends  along  the  concavo  edge  of  the  right 
kidney  and  on  the  right  side  of  the  vertebral  column  to  the  fourth  lum- 
bar vertebra. 

The  inferior  ascending  portion  is  situated  on  the  right  side  of  the 
vena-cava  and  the  right  renal  vessels,  on  the  left  side  of  the  aorta,  be- 
hind the  upper  part  of  the  root  of  the  mesentery,  the  superior  mesen- 
teric artery,  and  the  great  mesaraic  vein. 

Its  left  and  concave  portion  closely  embraces  the  right  half  of  the 
pancreas. 

§ 2158.  The  duodenum  is  generally  broader  at  its  origin  than  in 
any  other  part  ; its  concave  face  is  corrugated,  its  convex  face  is 
smooth  and  tense. 

It  differs  from  the  other  portions  of  the  small  intestine  by  its  situa- 
tion and  the  firm  manner  in  which  it  is  kept  in  place,  and  also  by  its 
greater  extent  and  the  less  regularity  of  its  folds. 

B.  MEMBRANES  OF  THE  SMALL  INTESTINE. 

§ 2159.  The  small  intestine  is  covered  externally  in  all  its  extent 
by  the  peritoneum,  and,  except  the  duodenum,  it  is  attached  to  the 
lumbar  portion  of  the  vertebral  column  by  a long  fold  of  this  mem- 
brane, termed  the  mesentery  (raese/nterium) . 

Below  this  peritoneal  tunic  is  the  thin  muscular  membrane,(l)  which 
is  about  a third  of  a line  thick. 

The  external  or  longitudinal  layer,  although  much  thinner  than  the 
internal,  with  which  it  is  very  intimately  united  and  which  is  never 
entirely  deficient,  surrounds  the  canal  almost  entirely. 

The  internal  layer  is  transverse  or  rather  oblique,  and  circumscribes 
it  entirely. 

The  vascular  membrane  presents  nothing  remarkable. (2) 

The  small  intestine  differs  from  the  other  portions  of  the  intestinal 
canal  principally  by  the  arrangement  of  its  inner  or  mucous  mem- 
brane.(3)  The  principal  character  which  distinguishes  this  membrane 
is  the  singular  increase  of  its  extent  and  the  greater  development  of 
its  surface,  compared  Avith  that  of  the  external  membranes,  especially 
the  muscular  and  the  peritoneal  tunics. 

This  enlargement  depends  on  its  folding  from  without  inward,  which 
gives  rise  to  two  kinds  of  folds,  the  great  and  the  small  folds. 

The  great  folds  are  termed  valves  ( valvules ),  and  the  small,  villosi- 
ties  (villi). 

(1)  V.  Malacarne,  Sulla  structura  anatomica  dette  intestine;  in  the  Memorie 
della  societa  italiana,  vol.  x.,  p.  27-62. 

(2)  B.  S.  Albinus,  Diss.  de  arteriis  et  venis  intesiinorum  hominis,  Leyden,  1736. 
— J.  Bleuland,  Vasculorum  in  intestinorum  tenuium  tunicis  subtilioris  anatomes 
opera  detegendorum  description  Utrecht,  1797. 

(3)  Helvetius,  loc.  cit. — D.  G.  Galeati,  De  cribriformi  intestinorum  tunicâ  ; in  the 
Comm.  Bonom.,  vol.  i.,  1731,  p.  359-370. 


OF  THE  DIGESTIVE  SYSTEM. 


265 


Both  are  developed  principally  at  the  upper  extremity  of  the  small 
intestine.  They  diminish  much  in  number  and  size  from  the  origin  of 
this  organ  to  its  termination. 


C.  VALVES. 

§ 2160.  The  valves  are  three  lines  high  at  the  upper  part  of  the 
small  intestine. 

They  have  a transverse  direction,  and  most  of  them  occupy  the 
whole  circumference  of  the  intestine,  so  that  they  form  circles  which 
circumscribe  it.  But  they  divide  once  or  twice  in  their  course,  and 
also  communicate  with  each  other  by  oblique  or  perpendicular  eleva- 
tions, which  generally  are  less  prominent  and  much  shorter  than 
they;  three  or  four  of  them  always  exist  between  each  pair  of 
valves. 

They  are  very  numerous,  being  only  a few  lines  distant  from  each 
other. 

There  are  but  very  few  at  the  lower  part  of  the  small  intestine,  but 
before  entirely  disappearing,  they  gradually  diminish  in  elevation  and 
breadth. 

They  are  formed  only  by  the  inner  membrane  and  by  the  vascular 
tunic  of  the  intestine,  so  that  they  cannot  move  themselves,  but  they 
are  floated  by  the  motions  caused  by  the  muscular  tunic  in  the  fluids 
within  the  intestinal  canal.  When  we  cut  the  intestine,  we  observe 
that  they  are  directed  towards  each  other,  so  that  if  we  immerse  the 
organ  in  water  they  cover  one  another  like  the  tiles  of  a roof. 

Hence  the  term  valvulœ  conniventes , applied  to  them  by  Kerckring  ; 
but  it  is  wrong  to  ascribe  this  discovery  to  this  anatomist,  from  which 
error  they  have  deiived  the  name  of  the  valves  of  Kerckring  ( valvulœ 
Kerckringii) . 

An  artery  and  vein  usually  pass  through  the  base  of  each  valve. 

These  valves  delay  the  course  of  the  substances  in  the  alimentary 
canal;  hence  their  greater  development  at  the  upper  part  of  the  small 
intestine  is  curious,  since  the  fluid  contained  in  this  portion  possesses 
the  most  nutritious  particles. 

They  are  no  less  curious  as  a peculiar  character  of  the  human  or- 
ganism. Morgagni  mentions  their  absence  in  some  ruminantia.(l) 
We  have  also  looked  for  them  in  vain  in  many  mammalia  of  all  orders, 
even  among  the  apes:  In  fact  several  fishes  present  very  analogous 

transverse  valves,  which  are  often  very  numerous  ; but  they  occupy 
the  end  of  the  intestinal  canal  in  these  animals,  and  they  have  no  vil- 
losities.  They  present  also  this  character  in  those  reptiles  in  which 
we  have  seen  them.  (2) 

(1)  Ep.  an.,  xiv.,  p.  20. 

(2)  Deutsches  Archiv,  für  die  Physiologie , vol.  iii.,  part  ii. 


266 


DESCRIPTIVE  ANATOMV. 


We  may  then  say,  in  order  to  express  the  preceding  proposition 
more  precisely,  that  man  is  the  only  being  possessing  both  transverse 
folds  and  villosities  in  the  small  intestine,  and  alone  presents  the  union 
of  these  two  organic  arrangements,  which  are  found  separately  in 
other  animals.  In  fact  most  mammalia  and  birds,  as  also  some  rep- 
tiles and  fishes,  present  only  the  villosities,  and  but  a few  genera  of 
the  last  two  classes  the  transverse  folds. 

D.  VILLOSITIES. 

§2161.  The  villosities(l)  are  small  thin  prolongations,  which  arc 
generally  rounded,  sometimes  cylindrical,  sometimes  conical,  and  ter- 
minated insensibly  in  a point  ; finally,  sometimes  enlarged  at  their  loose 
extremity  ; they  are  attached  to  the  mucous  membrane  ; hence,  the 
term  villous  tunic  ( tunica  villosa ),  often  applied  to  it. 

The  villosities  cover  all  the  inner  face  of  the  mucous  membrane  of 
the  small  intestine,  being  very  compact  at  its  upper  part,  while  at  the 
lower  part  they  are  more  or  less  remote  from  each  other.  In  regard  to 
their  form,  some  authors,  as  Galeali,  admit  that  they  are  cylindrical, 
or  pointed  at  the  origin  of  the  intestine,  and  conical  at  its  termination, 
but  this  difference  is  not  constant.  We  have  always  found  on  the  con- 
trary, which  agrees  with  the  observations  of  Hewson,  that  the  villosi- 
ties at  the  upper  part  of  the  canal  are  broader  in  proportion  to  their 
length,  and  that  from  their  form,  they  resemble  the  valvulæ  conniven- 
tes,  while  as  those  of  the  lower  part  were  thinner,  elongated,  and  even 
sometimes  longer  than  the  preceding.  They  are  about  one  quarter  of 
a line  long.  As  they  are  arranged  very  compactly,  and  as  there  are 
about  four  thousand  in  a square  inch,  we  may  estimate  their  whole 
number  as  more  than  a million,  which  is  very  moderate. 

When  examined  by  the  microscope,  they  appear  formed  of  a granu- 
lar substance,  and  their  surface  is  not  perfectly  smooth,  although  it  is 
not  indented.  When  the  blood-vessels  of  the  intestinal  canal  are  in- 
jected, the  villosities  are  not  only  more  apparent  and  filled  with  injec- 
tion, but  their  surface  is  more  uneven,  because  a vascular  net-work  is 
developed  in  it. 

When  the  lymphatics  are  injected,  we  see  on  their  surface  a net- 
work formed  by  these  vessels. 

They  are  then  composed  of  cellular  tissue,  in  which  are  blood-ves- 
sels and  lymphatics,  the  parietes  of  which  are  not  distinct  from  its  sub- 
stance. It  has  long  been  disputed,  whether  the  villosities  open  on 
their  surface  or  not  1 

(1)  Beside  the  works  of  Hclvcti  us,  Galeati,  and  A.  Mec.kcl,  consult  particularly  on 
the  villosities: — J.  N.  Lieberkuhn,  De  fabricû.  ct  actione  villorum  intestinorum 
tenuium  hominis,  Leyden,  1745. — Hewson,  in  his  Exp.  inq.,  vol.  ii.  c.  xii. — R.  A. 
Hedwig,  Disquisitio  ampullarxim  Liebcrkuhnii  physica-microscopica , Leipsic,  1797. 
— C.  A.  Rudolphi,  in  his  Abhandlungen,  &c.  p.  39'. 


OP  THE  DIGESTIVE  SYSTEM. 


267 


Excellent  observers,  as  Lieberkuhn,  Hunter,  Cruikshank,  Hewson, 
Hedwig',  and  Bleuland,  admit  these  openings,  and  assert  they  have 
seen  them.  Lieberkuhn  and  Bleuland  think  there  is  generally  only 
one  at  the  extremity  of  each  villosity,  rarely  several.  Others  mention 
more,  and  assert  they  are  situated  in  the  same  place.  When  a minute 
injection  has  raised,  inflated,  and  rendered  the  villosities  cylindrical, 
they  appear  spungy,  and  perforated  at  their  extremity,  while  they  re- 
main smooth  and  united  on  the  sides.  We  cannot  consider  these  open- 
ings as  arising  from  accidental  ruptures,  since  they  are  empty  and  en- 
tirely separated  from  each  other,  and  they  also  occur  only  in  determi- 
nate points,  while  in  ruptures  of  a part,  the  vessels  of  which  are  filled 
with  injection,  we  should  necessarily  see  this  injection.  Cruikshank 
and  Hunter  have  counted  twenty  of  these  openings  in  the  villosities, 
which  were  not  injected,  but  only  gorged  with  chyle. 

The  arguments  of  Rudolphi  who  has  never  seen  these  openings, 
do  not  refute  the  assertions  of  the  observers  above  mentioned.  He 
does  not  mention  Hewson  at  all.  The  diameter  of  the  openings 
figured  by  Cruikshank  and  Bleuland,  which  seems  too  great  to  be  cor- 
rect, may  depend  on  some  individual  peculiarity,  on  the  state  in  which 
the  activity  was  at  the  moment  of  death,  or  even  on  some  disease,  all 
which  circumstances  would  render  the  openings  more  perceptible. 
If  Hewson  has  not  figured  them  in  all  the  villosities,  it  may  depend 
either  on  their  diameter  or  on  the  situation  of  the  villosities,  and  the 
manner  in  which  they  were  lighted. 

Thus,  although  these  ' openings  are  not  necessary  to  explain  the 
phenomenon  of  absorption,  they  seem  to  exist. (1) 


E.  GLAND3. 

§ 2162.  The  inner  membrane  of  the  small  intestine  is  covered  with 
numberless  muciparous  glands,  which  differ  in  their  size  and  arrange- 
ment. 

In  its  whole  length,  and  on  all  its  surface,  there  are  very  numerous 
distinct  glands,  which  are  the  smallest  (G.  mucosœ , s.  cryptez  minima ), 
and  which  cannot  be  seen  without  a microscope. (2) 


(1)  Strictly  speaking-,  the  question  is,  whether  the  pores  of  the  villosities,  for  they 

must  necessarily  exist  in  every  org-anic  or  inorganic  substance,  possess  a special 
organization,  so  that  they  may  be  compared  to  a certain  extent  with  the  lachrymal 
puncta  for  instance.  But  it  is  what  it  does  not  seem  to  be,  and  we  cannot  but  apply 
to  microscopical  observations, where  the  illusions  are  so  frequent  and  difficult  to  avoid 
the  axiom,  that  a negative  assertion  does  not  refute  a positive  one,  when  the  latter  is 
supported  by  good  authority.  The  researches  of  A.  Meckel,  the  brother  of  the 
author,  also  favor  Rudolphi’s  opinion.  This  anatomist  does  not  admit  vessels  in 
the  villosities  of  the  intestine,  and  thinks  that  the  injection  which  penetrates  into 
them,  transudes  through  the  parietes  of  the  arterial  terminations,  to  be  distributed  in 
the  cellular  tissue  which  forms  them.  Farther,  he  has  found,  contrary  to  the  asser- 
tion of  all  his  predecessors,  that  the  villosities  are  always  flattened  layers,  most 
generally  turned  on  their  axes,  and  often  folded  on  each  side,  so  as  to  form  a semi- 
canal or  a groove,  which  arrangements  vary  infinitely,  and  by  which  he  explains  the 
different  appearances  described  by  authors  before  him.  F.  T. 

(2)  Galeati,  loc.  cit, — Lieberkuhn,  De  rims  intesUnormn. 


S68 


DESCRIPTIVE  ANATOMY. 


Others  are  much  larger,  and  divided  into  two  classes,  the  solitary 
( G . solitariœ ) and  the  agglomerate  (G.  agminatœ).  The  first  are 
termed  also  the  glan  ds  of  Brunner,  (1)  and  the  others  the  glands  of  ' 
Peyer. { 2) 

The  glands  of  Brunner  are  seen  particularly  at  the  commencement 
of  the  small  intestine,  especially  in  the  duodenum,  where  they  appear 
in  the  form  of  small,  flat,  rounded,  lenticular  bodies,  at  most  one  line  in 
diameter,  situated  on  the  posterior  face  of  the  mucous  membrane,  and 
which  open  into  the  cavity  of  the  intestine  by  broad  orifices. 

When  these  simple  glands  are  very  large,  and  project  considerably 
above  the  inner  face  of  this  portion,  or  the  other  parts  of  the  canal,  it  is 
al  wajrs  from  a morbid  state. 

The  glands  of  Peyer  rarely  exist  except  in  the  ileon,  where  they  en- 
large much  from  the  commencement  to  the  end  of  the  intestine. 

They  form  about  thirty  masses,  which  are  generally  oblong  and 
rounded,  seldom  triangular  or  almost  square,  the  longitudinal  axis  of 
which  is  parallel  to  that  of  the  intestinal  canal  ; they  are  rarely  more 
broad  than  long,  and  they  do  not  exist  on  the  side  of  the  intestine  cor- 
responding to  the  mesentery,  but  on  the  lateral  portions,  particularly 
the  anterior. 

They  are  not  prominent,  or  at  least  project  but  little  above  the  sur- 
face of  the  intestine,  and  they  are  distinguished  only  by  the  intestine 
being  less  transparent  in  the  points  they  occupy.  They  form  on  the 
posterior  face  of  the  mucous  membrane,  a thin  layer,  which  is  com- 
posed of  bright,  transparent,  rounded,  and  slightly  depressed  points, 
and  of  darker  edges  in  the  spaces  between  these  points. 

They  vary  in  length  from  some  lines  to  three  or  four  inches  ; they 
are  about  nine  lines  broad. 

At  the  upper  part  of  the  ileon  they  are  five  or  six  inches  distant  from 
each  other  ; but  at  the  lower  part,  and  near  its  termination,  they  are 
almost  blended  with  each  other,  and  sometimes  form  in  the  loose  por- 
tion of  the  edge  of  the  small  intestine,  an  almost  uninterrupted  layer 
eight  inches  long. 


F.  FUNCTIONS  OF  THE  SMALL  INTESTINE. 

§ 2163.  The  inner  membrane  of  the  small  intestine  secretes  the  in- 
testinal mucus  ( mucus  intestinalis ) and  the  intestinal  liquid  ( liquor  en- 
terions), which  probably  form  one  and  the  same  fluid,  partially  favor- 
ing the  assimilation  of  the  alimentary  substances  by  its  action  upon 
them,  and  also  their  progress  by  the  lubricating  layer  on  the  surface 
of  the  intestine.  This  progress  is  caused  by  the  muscular  tunic,  which 
alternately  dilates  and  contracts  from  the  commencement  of  the  small 
intestine  to  its  termination,  so  as  to  send  forward  its  contents  in  the 

(1)  Brunner,  Glandulœ  intestini  duodcni,  s.  pancreas  secundarius , Frankfort, 
1715. 

(2)  C.  Peyer,  De  glandulis  intestinorum,  Schafhouse,  1677. 


OF  THE  DIGESTIVE  SYSTEM. 


269 


same  direction.  In  passing  through  the  small  intestine,  but  particu- 
larly in  the  duodenum,  and  from  the  influence  of  bile,  aided  by  that  of 
the  pancreatic  juice,  the  chyme  is  separated  into  two  portions,  the 
chyle  ( chijlus ),  a whitish  fluid,  similar  in  its  chemical  properties  to  the 
blood  and  th ef cecal  matter  [faces).  The  chyle  is  absorbed  by  the  vil- 
losities  of  the  intestine,  whence  it  passes  into  the  lymphatic  vessels,  and 
probably  also  into  the  meseraic  veins.  The  feces  proceed  into  the 
large  intestine. 

III.  LARGE  INTESTINE. 

§ 2164.  The  large  intestine  ( intestinum  crassum , s.  colon ) differs  from 
the  small  intestine  in  its  situation  and  attachments,  form,  length, 
breadth,  and  the  arrangement  of  its  tunics. 

A.  SITUATION  AND  ATTACHMENTS. 

§ 2165.  The  large  intestine  describes  an  arch,  the  direction  of  which 
is  from  below  upward,  then  goes  transversely  from  right  to  left,  and  finally 
from  above  downward,  begins  at  the  lower  extremity  of  the  small  in- 
testine, and  terminates  at  the  anus.  It  commences  at  the  right  iliac 
region,  but  not  always  in  the  same  point.  This  point  is  generally 
situated  at  the  upper  extremity  of  the  anterior  face  of  the  right  iliacus 
muscle,  between  this  and  the  psoas  muscle  ; sometimes,  also,  it  occurs 
much  lower,  and  sometimes  much  higher,  before  the  right  psoas 
muscle.  The  small  and  the  large  intestine  are  intimately  attached  in 
this  place  to  the  iliacus  muscle  by  a short  cellular  tissue,  and  the  first 
is  there  continuous  from  within  outward,  and  from  below  upward  with 
the  second. 

The  higher,  that  is,  the  more  abnormal  the  union  between  the  two, 
the  more  similar  the  arrangement  to  that  in  the  fetus. 

At  the  point  of  union  the  commencement  of  the  colon  presents  a 
prominence  which  extends  below  its  terminating  extremity,  and  is 
termed  the  cæcum , and  the  cœcal  appendix. 

B.  DIVISION  OF  THE  LARGE  INTESTINE. 

A.  ILEO-GOLIC  VALVE. 

§ 2166.  The  small  intestine  is  suddenly  continuous  with  the  large, 
at  the  point  mentioned,  so  that  it  enters  there  at  an  acute  angle  from 
below  upward,  from  left  to  right,  and  from  within  outward,  for  about  an 
inch,  and  there  forms  a prominence  termed  the  ileo-colic  valve , (1)  or 
the  valve  of  Bauhin  [valvula  ileo-colica , s.  Bauhini).  This  valve  is 

(1)  L.  Heister,  De  valoula  coli,  Altdorf,  1718. — J.  N.  Licberkulm,  De  valvulâ. 
coli,  Leyden,  1739.— Haller,  De  valvula  coli,  Göttinnen.  1742. — J.  M.  Rœderer,  De 
valvula  coli,  Strasburrr,  1768. 

Vol.  111 


35 


270 


D E S C ill  f T IV E ANA  3'  OBI  V 


composed  of  two  layers,  a superior,  generally  a little  narrower  and  al- 
most horizontal,  which  forms  nearly  a right  angle  with  the  ascending 
portion  of  the  colon,  and  an  inferior,  which  is  broader,  and  describes  a 
more  acute  angle  with  this"  same  portion. 

Between  the  two  layers  is  a transverse  and  oblong  opening,  which 
is  the  slightly  contracted  orifice  of  the  small  intestine. 

Each  is  formed  by  the  inner  membrane  of  the  vascular  tunic,  and  the 
circular  fibres  of  the  muscular  membrane  of  the  large  and  the  small 
intestine  which  are  turned  over  in  this  place,  while  the  longitudinal 
fibres,  and  the  peritoneal  tunic,  which  do  not  fold,  pass  like  a bridge 
from  the  loose  portion  of  the  small  intestine  on  the  large.  The  muscu- 
lar tunics  of  the  two  intestines  are  united  with  each  other  at  their  ex- 
ternal face  by  mucous  tissue,  and  when  we  consider  only  the  valve, 
they  form  its  most  internal  part  or  its  centre.  When  we  carefully  de- 
stroy the  cellular  tissue  which  unites  them,  the  valve  entirely  disappears, 
the  small  intestine  opens  directly  into  the  large  by  a broader  orifice  than 
the  rest  of  its  caliber,  in  the  form  of  a trumpet,  and  then  the  union  of 
the  two  intestines  still  more  resembles  that  of  the  esophagus  with  the 
stomach,  since  in  both  places  the  line  of  demarkation  is  evidently  indi- 
cated by  a very  evident  difference  in  the  texture  of  the  inner  membrane, 
by  the  greater  size  of  the  lower  portion  into  which  the  other  opens, 
and  by  its  projecting  above  this  latter,  giving  rise  to  a cul-de-sac. 

§ 2167.  In  the  normal  state  the  ileo-colic  valve  separates  the  small 
from  the  large  intestine,  so  as  to  allow  the  substances  contained  in  the 
first  to  pass  into  the  second,  but  entirely  preventing  them  from  reas- 
cending  from  the  latter  into  the  former.  This  effect  depends  both  on 
the  action  of  the  muscular  fibres  and  the  form  of  the  valve. 

B.  CECUM  AND  VERMIFORM  APPENDIX. 

§ 2168.  The  portion  of  small  intestine  which  passes  beyond  the 
colon,  (§  2166)  is  composed  of  the  cæcum  ( intestinum  cæcum),  and  of 
the  vermiform  appendix  (appendicula  vermiformis), (1)  which  originally 
form  but  one,  and  which  do  not  begin  to  be  distinct  until  after  the  early 
years  of  life. 

§ 2169.  The  cæcum  is  elongated,  triangular,  and  as  large  as  the 
rest  of  the  colon.  It  extends  from  an  inch  to  an  inch  and  a half  beyond 
the  terminating  portion  of  the  small  intestine.  The  muscular  fibres 
in  particular,  are  very  irregular,  and  very  much  interlaced  near  its 
closed  extremity.  It  is  terminated  by  a blunt  summit,  of  which  the 
vermiform  appendix  is  the  prolongation  ;(2)  the  latter,  however,  rarely 
leaves  its  centre,  but  arises  from  its  left  side  a little  posteriorly.  It  is 

(1)  J.  N.  Lieberkuhn,  De  valvula  coli  et  usu  processus  vermicularis , Leyden, 
1739. — J.  Vosse,  De  intestino  cœco  ejusque  appendice  vermiformi,  Gottingen,  1749. — 
Van  den  Busch,  Dc  intestino  caeca  ejusque  processu  vermiformi,  Gottingen,  1814. 

(2)  Louyer  Villermay,  Observations  pour  servir  à l'histoire  des  inflammations  de 
l'appendice  du  cæcum  ; in  the  Archiv,  gêner,  de  médecine,  vol.  v.  p.  246. 


OF  THE  DIGESTIVE  SYSTEM. 


271 


the  narrowest  part  of  the  alimentary  canal.  A small  fold  of  peritoneum 
unites  it  to  the  lower  extremity  of  the  mesentery,  and  to  the  spermatic 
vessels  which  are  situated  below  it. 

This  appendix  is  generally  about  three  inches  long. 

Excepting  its  orifice,  which  is  a little  broader  than  the  rest,  and  tun- 
nel-shaped, its  breadth  is  nearly  equal  in  every  part,  and  is  about  two 
lines.  It  is  terminated  in  a blunt  summit.  A transverse  fold,  a kind 
of  valve,  sometimes,  but  not  always,  separates  it  from  the  ccecum.(l) 

Near  the  end  of  the  cæcum,  the  three  bands  which  form  the  longi- 
tudinal muscular  layer  of  the  large  intestine,  unite  to  form  a thinner 
and  uniformly  expanded  membrane,  which  is  extended  on  the  vermi- 
form appendix,  where  it  assumes  the  same  arrangement. 

§ 2170.  The  parietes  of  this  appendix  are  as  thick  as  those  of  the 
large  intestine,  and  its  inner  membrane  forms,  from  its  great  number 
of  large  and  extremely  compact  muciparous-  glands,  a very  complex 
net-work,  similar,  although  much  larger  than  that  formed  by  the  ine- 
qualities of  the  inner  face  of  the  rest  of  the  colon. 

Not  unfrequently,  although  not  always,  this  inner  face  also  presents 
larger  transverse  prominences,  folds  similiar  to  those  at  the  orifice  of 
the  appendix. 

The  vermiform  appendix  is  not  always  situated  exactly  in  the  same 
place  ; it  sometimes  descends  almost  entirely  into  the  pelvis,  the  edge 
of  its  mesentery  opposite  to  that  which  adheres  to  it,  being  loose. 
Sometimes  it  goes  upward,  passing  under  the  commencement  of  the 
large  intestine.  Sometimes  then  it  assumes  this  ascending  direction  in 
its  whole  extent,  and  sometimes  its  lower  extremity  again  curves 
downward  in  a greater  or  less  extent. 

C.  ASCENDING  COLON. 

§ 2171.  The  large  intestine  begins  with  the  right  or  ascending 
colon  (I.  colon  dextrum , s.  ascendens))  which  is  its  shortest  portion,  as- 
cends before  the  right  kidney,  with  wrhich  it  is  intimately  united  by  the 
right  lumbar  meso-colon , and  extends  to  the  anterior  part  of  the  lower 
face  of  the  right  lobe  of  the  liver.  In  this  place  it  describes  a right  or 
an  acute  angle  under  the  base  of  the  gall-bladder,  with  which  it  has 
normally  no  connection,  goes  to  the  right,  and  is  continuous  with  the 
transverse  colon. 

D.  TRANSVERSE  COLON. 

§ 2172.  The  transverse  colon  (colon  transversmn)  is  attached  to  the 
posterior  wall  of  the  abdomen  by  a much  broader  fold  of  the  peritoneum 
than  that  of-  the  preceding,  termed  the  transverse  meso-colon  ; it  is  situ- 
ated below  the  stomach,  with  which  it  is  always  more  or  less  intimate- 

(1)  Morgagni,  Advers.  anat.  Anim.  XI V—  Bonazzoli,  Observ.  in  intesi.  et  rcnibus 
habilœ  ; in  the  ( Somm . Horton.,  vol  ii  p.  2.  p.  1.38 


272 


DESCRIPTIVE  ANATOMY, 


ly  united  by  the  great  epiploon,  and  always  descends  more  or  less  be- 
fore the  folds  of  the  small  intestine,  usually  to  the  umbilical  region, 
sometimes  even  into  the  small  pelvis.  It  is  always  much  longer  than 
the  ascending  colon,  and  sometimes  very  much  exceeds  it  in  size,  and 
then  describes  several  circumvolutions.  It  extends  from  the  right  to 
the  left  side.  Its  two  extremities  are  intimately  attached  to  the  duo- 
denum by  the  meso-colon,  which  is  much  shorter  in  these  two  parts 
than  in  its  centre.  On  the  centre  of  the  anterior  face  of  the  right  kid- 
ney, and  at  the  lower  extremity  of  the  spleen,  it  is  continuous  with  the 
descending  colon,  describing  either  an  arch,  or  a more  or  less  acute  and 
sometimes  a double  angle. 

E.  DESCENDING  COLON. 

§ 2173.  The  descending  colon  (I.  colon  descendens)  extends  from 
the  lower  extremity  of  the  spleen  to  the  pelvis,  passing  along  the  lower 
half  of  the  anterior  face  of  the  left  kidney,  then  the  quadratus  lumborum 
muscle,  and  finally  the  upper  and  inner  part  of  the  left  iliacus  muscle. 
It  is  continuous  with  the  rectum  before  the  right  sacro-iliac  symphasis. 

It  is  attached  to  the  posterior  wall  of  the  abdomen,  above  by  a short, 
and  below  by  a very  large  fold  of  the  peritoneum. 

This  lower  part  projects  more  or  less  forward,  and  to  the  right,  and 
sometimes  adheres  to  the  cæcum  ; it  describes  a curve,  hence  it  is  called 
the  *S,  or  sigmoid  flexure  of  the  colon  ( flexura  sigmoidea,  s.  iliaca , s. 
S.  romanum ), 

F.  RECTUM. 

§ 2174.  The  rectum  (7,  rectum)  is  the  last  portion  of  the  intestinal 
canal,  and  it  opens  externally  by  the.  anus.  It  begins  at  the  lower 
extremity  of  the  colon,  is  attached  to  the  left  half  of  the  anterior  face  of 
the  sacrum  in  a slight  portion  of  its  upper  extremity,  by  a short  fold  of 
the  peritoneum,  termed  the  meso-rectum , and  in  the  rest,  simply  by  cel- 
lular tissue  ; it  goes  from  left  to  right,  and  from  above  downward,  so 
long  as  it  is  surrounded  by  the  peritoneum,  and  does  not  begin  to  de- 
scend in  a straight  fine  until  this  membrane  leaves  it. 

Sometimes  it  descends  in  the  pelvis  on  the  right,  and  not  on  the  left 
side  of  the  sacrum.  In  one  case  of  this  kind  observed  by  us,  the  great 
inferior  left  curve  or  the  sigmoid  flexure  of  the  colon,  advanced  very 
much  toward  the  right,  united  very  intimately  at  its  centre  with  the 
commencement  of  the  ascending  colon,  and  was  attached  in  this  man- 
ner to  the  right  side.  Its  ascending  and  descending  portions  were  also 
attached  and  separated  a little  from  each  other  interiorly.  Below  this 
point,  the  commencement  of  the  curve  and  that  of  the  rectum  were  also 
united  by  a fold  of  peritoneum,  whence  there  was  a considerable  de- 
pression, which  might  easily  receive  a portion  of  small  intestine  several 
inches  long,  and  thus  give  rise  to  an  internal  hernia. 


OF  THE  DIGESTIVE  SYSTEM. 


273 


Although  we  may  justly  consider  the  rectum  as  the  lower  part 
of  the  large  intestine,  the  rectum  differs  from  it  in  several  respects. 
In  fact  : 

1st.  It  is  almost  always  much  broader,  and  in  this  respect  it  ex- 
ceeds more  or  less  the  other  portions. 

2d.  The  peritoneum  covers  it  only  in  its  upper  region  ; even  ihere 
it  covers,  in  most  of  its  extent,  only  its  anterior  face,  and  forms  no  epi- 
ploic appendages  on  its  surface. 

3d.  Its  muscular  fibres  are  much  stronger,  and  the  longitudinal 
layer  surrounds  it  in  every  part. 

The  inner  membrane  is  also  smooth  and  filled  with  simple  mucipa- 
rous glands,  but  these  glands  are  smaller  and  fewer.  (1) 


(1)  The  recto-vesical  operation  for  stone,  introduced  by  SansoD,  which  becomes 
more  extensively  known  every  day  (J.  L.  Sanson,  Des  moyens  de  parvenir  à la  vessie 
par  le  rectum , Paris,  1817),  requires  a more  detailed  description  of  the  anatomical 
relations  of  the  rectum.  Taken  as  a whole,  this  intestine  extends  from  the  upper 
strait  of  the  pelvis  to  the  anus.  Its  direction  is  at  first  a little  oblique  from  left  to 
right,  and  it  curves  toward  the  lower  part  of  the  cavity  of  the  pelvis  to  go  from 
behind  forward,  under  the  bladder,  to  the  level  of  the  prostate  gland,  below  which 
it  again  curves  from  above  downward,  and  a little  from  before  backward.  We  may 
then  consider  it  formed  by  three  pkrts  separated  by  these  two  curves,  and  distinct 
in  their  situation  and  structure,  and  the  nature  and  importance  of  their  connections. 
The  first  or  superior  is  directed  from  above  downward,  and  a little  obliquely  froni 
left  to  right  ; it  extends  from  the  end  of  the  sigmoid  flexure  of  the  colon  to  the  place 
where  the  intestine  leaves  its  peritoneal  envelop,  and  curves  to  go  below  the  bladder  : 
it  forms  more  than  half  of  the  rectum.  It  is  tortuous,  loose,  smooth,  covered  by  the 
peritoneum,  and  attached  loosely  to  the  posterior  wall  of  the  cavity  of  the  pelvis  by 
a fold  of  this  membrane.  The  second  or  central  part  is  included  between  the  two 
curves,  and  is  about  three  inches  long;  its  direction  is  oblique  from  above  down- 
ward and  from  behind  forward  ; it  is  slightly  curved  in  the  same  direction,  is  fixed 
and  immovable,  and  constantly  corresponds  posteriorly  to  the  lower  part  of  the  sa- 
crum, the  coccyx,  and  the  base  formed  by  the  ischio-coccygei  muscles  : forward  to 
the  base  of  the  bladder,  from  which  it  is  separated  downward  and  outward  by  the 
seminal  vesicles  and  the  vasa  deferentia,  and  still  lower  by  the  prostate  gland  : 
finally,  on  the  sides  to  an  abundance  of  cellular  tissue.  It  differs  in  structure  and 
organization  from  the  upper  portion,  being  wholly  destitute  of  the  peritoneum,  ex- 
cept sometimes  at  the  highest  part  of  its  anterior  face,  when  the  bladder  is  consi- 
derably retracted  ; its  muscular  coat  also  is  much  thicker,  and  formed  of  much 
stronger  and  more  numerous  longitudinal  fibres  ; it  is  every  where  surrounded  by 
a cellular  tissue,  compact  only  below  the  prostate  gland,  loose  and  very  abundant  in 
the  rest  of  the  circumference  of  the  intestine.  Finally  the  lower  portion  of  this 
latter  commences  below  and  on  a level  with  the  prostate  gland,  and  terminates  at 
the  anus.  It  varies  in  length  from  one  inch  to  an  inch  and  a half.  It  is  broader 
above  than  below.  Its  direction  is  oblique  from  above  downward,  and  a little  from 
before  backward.  Near  its  origin  it  is  every  where  surrounded  by  an  abundant 
cellular  tissue,  except  forward,  where  it  corresponds  to  the  prostate  gland  ; in  the 
rest  of  its  extent  it  is  enveloped  by  the  sphincters.  Its  structure  differs  much  from 
that  of  the  other  portions.  In  fact,  when  the  rectum  curves  a second  time  below 
the  prostate  gland,  its  fleshy  tunic,  which  is  very  thick,  and  composed  of  numerous 
longitudinal  fibres,  terminates  suddenly;  the  mucous  membrane  alone  extends 
to  the  skin,  surrounded  by  the  round  muscular  fibres  of  the  sphincters,  which  meet 
and  form  a kind  of  ring,  much  thinner  at  its  origin  than  on  the  side  of  the  skin, 
where  it  becomes  much  thicker,  and  gives  rise  to  two  caudiform  prolongations,  of 
which  the  anterior,  the  longer,  goes  toward  the  bulb  of  the  urethra,  and  there  blends 
with  the  bulbo-cavernosus  muscle,  while  the  posterior  proceeds  to  the  coccyx.  This 
muscular  ring  is  covered  internally  by  the  end  of  the  mucous  tunic  of  the  intes- 
tine, is  united  forward  and  upward  to  the  prostate  gland,  and  is  adapted  in  every 
part  to  very  abundant  and  fatty  cellular  tissue.  Thus  the  upper  portion  of  the 


274 


DESCRIPTIVE  ANATOMY. 


C.  FORM. 

§ 2175.  The  large  intestine  is  not  uniformly  cylindrical  like  the 
other  sections  of  the  intestinal  canal,  but  presents  numerous  elevations 
and  depressions,  which  render  its  surface  uneven.  In  fact  the  longi- 
tudinal fibres  are  there  united  in  three  bands  separated  by  spaces,  and 
the  muscular  membrane  considered  generally  is  shorter  than  the  inner 
tunics.  Hence  it  follows,  that  when  the  cavity  of  the  large  intestine 
receives  the  residue  of  digestion,  it  forms  between  the  three  bands  three 
series  of  rounded  bursae  which  vary  in  size,  and  are  termed  cellules 
( cellulœ , s.  haustra). 

These  bursæ  are  all  similar  but  are  not  perfectly  alike,  and  are  no 
where  arranged  symmetrically.  Their  origin  from  the  cause  men- 
tioned proved  by  the  fact  that  on  cutting  the  bands  the  inequalities 
disappear  in  the  place  corresponding  to  the  incision,  and  the  canal 
there  possesses  a perfectly  cylindrical  form. 

D.  LENGTH  AND  BREADTH. 

§ 2176.  The  length  of  the  large  intestine  is  about  five  feet,  and  its 
breadth  when  moderately  distended  varies  between  an  inch  and  a half 
and  two  inches. 


E.  ARRANGEMENT  OF  THE  TUNICS. 

A.  PERITONEAL  COAT. 

§ 2177.  In  most  of  its  extent,  especially  in  its  ascending  and  de- 
scending portions,  the  large  intestine  is  covered  by  the  peritoneum  only 
forward  and  on  its  sides  and  not  on  its  posterior  face,  which  is  attached 
to  the  adjacent  parts  only  by  very  loose  cellular  tissue.  The  trans- 
verse portion,  on  the  contrary,  is  every  where  surrounded  by  the  peri- 
toneum. From  the  loose  portion  of  the  peritoneal  coat  arise  the 
epiploic  appendages  ( appendicces  epiploicce). 

B.  MUSCULAR  MEMBRANE. 

§ 2178.  The  muscular  membrane  of  the  large  intestine,  except 
the  rectum,  is  thinner  even  than  that  of  the  small  intestine.  It  is 
composed,  as  in  every  other  part,  of  longitudinal  and  of  transverse 
fibres. 

rectum  is  movable,  and  covered  by  the  peritoneum,  while  the  middle  and  inferior 
parts,  forming-  together  about  at  least  four  inches,  arc  surrounded  in  every  part  by 
an  abundance  of  cellular  tissue,  and  are  attached,  but  have  no  peritoneal  envelop. 

F.  T; 


OF  THE  DIGESTIVE  SYSTEM, 


275 


The  longitudinal  fibres  distinguish  the  large  intestine  from  all  the 
other  portions  of  the  intestinal  canal  in  this  respect,  that  generally 
speaking,  they  are  united  in  three  bands,  situated  at  nearly  equal  dis- 
tances from  each  other,  about  from  four  to  six  lines  broad,  which  gra- 
dually increase  in  thickness  from  the  circumference  to  the  centre.  One 
of  these  bands  is  situated  posteriorly,  and  corresponds  to  the  point 
where  the  intestine  is  kept  in  place  by  the  peritoneum  ; the  second  is 
anterior,  and  proceeds  in  the  middle  portion  below  the  insertion  of  the 
epiploon  ; the  third  occupies  the  inside  of  the  ascending  and  the  de- 
scending portion,  and  the  lower  side  of  the  transverse  portion,  where  it 
is  perfectly  loose.  All  terminate  at  the  vermiform  process  and  in  the 
longitudinal  fibres  of  the  rectum. 

The  thickness  of  the  muscular  tunic  of  the  large  intestine  is  dimi- 
nished by  the  insulation  of  its  longitudinal  fibres. 

The  bands  are  much  thicker  the  greater  the  number  of  these  fibres, 
from  which  they  arise. 

They  are  about  half  a line  thick,  so  that  the  thickness  of  the  mus- 
cular tunic  is  considerable  in  the  parts  which  correspond  to  them. 

We  also  find  at  intervals  between  these  three  bands  several  distinct 
fasciculi  of  longitudinal  fibres  ; and  in  subjects  where  the  muscular 
system  is  very  much  developed,  the  large  intestine  is  entirely  sur- 
rounded by  a layer  of  these  fibres,  always  arranged,  however,  so  that 
the  intermediate  fibres  are  much  weaker  than  the  three  bands. 

The  circular  fibres  constantly  surround  the  whole  of  the  intestine, 
but  they  are  much  feebler  than  the  longitudinal. 

C.  MUCOUS  MEMBRANE. 

§ 2179.  The  mucous  membrane  is  perfectly  smooth  when  consi- 
dered superficially,  but  when  examined  attentively  we  observe  that  it 
is  uneven,  from  numerous  small,  rounded,  oblong,  compact  depressions, 
similar  to  the  points  of  pins.  These  depressions  give  it  a shaggy  or 
honey-comb  appearance,  as  is  seen  on  the  inner  face  of  the  mucous 
membrane  of  the  stomachal)  The  elevations  between  them  occupy 
a greater  space  than  they,  and  may  be  considered  as  corresponding  to 
the  villosities  of  the  small  intestine. 

The  arrangement  of  the  inner  membrane  of  the  two  sections  of  the 
intestinal  canal  differs  extremely  at  the  place  where  they  unite,  and 
these  two  sections  are  separated  by  a very  distinctline  of  demarkation, 
although  uninterruptedly  continuous  with  each  other. 

We  cannot  determine  whether  the  function  of  these  depressions  is  to 
secrete,  any  more  than  the  other  parts.  We  know,  however,  that  they 
are  not  surrounded  by  a substance  different  from  that  of  the  rest  of 
the  mucous  membrane  ; but  this  latter  appears  moie  thin  and  more 
transparent  in  these  points  than  in  the  intervals  between  them. 

(1)  This  has  already  been  observed  by  Hewson  (Exp.  inq.,  pt.  ii.,  p.  174). 


270 


DESCRIPTIVE  ANATOMY. 


The  mucous  membrane  of  the  large  intestine  presents  a great  num- 
ber of  muciparous  glands,  which  are  distinct  or  united  in  pairs  or  in 
triplets,  and  situated  near  each  other.  These  glands  represent  small 
depressions  with  a more  or  less  elevated  edge.  They  are  very  evident 
in  intestines  hardened  by  alcohol,  because  then  the  inner  membrane  is 
contracted,  and  assumes  à brownish  color.  They  are  formed  partly 
by  the  union  of  several  of  the  smallest  glands.(l) 

F.  MUSCLES  OF  THE  ANUS. 

§ 2180.  The  lower  extremity  of  the  rectum  is  subject  to  the  in- 
fluence of  the  will,  and  is  moved  by  several  muscles,  the  sphincters, 
the  levatores  ani , and  the  transversi  perinei  muscles.  We  shall  de- 
scribe here  only  the  sphincters,  referring  the  history  of  the  others  to 
the  chapter  on  the  genital  organs,  with  which  they  are  more  intimately 
connected  than  with  the  anus. 

§ 2181.  The  anus  has  two  sphincters , an  internal  and  an  external, 
both  of  which  result  from  a greater  development  of  the  circular  fibres 
of  the  rectum. 


A.  SPHINCTER  ANI  INTERNUS. 

§ 2182.  The  sphincter  ani  internus  muscle  proves  very  evidently 
the  origin  above  mentioned  ; for  the  longitudinal  fibres  of  the  rectum 
are  deficient  from  three  to  four  lines,  the  circular  fibres  become  redder 
and  thicker,  have  the  form  of  a flattened  ring,  which  extends  beyond 
the  longitudinal  fibres.  This  ring  is  three  or  four  lines  high  and  about 
two  lines  thick,  and  it  is  situated  directly  under  the  skin. 

D.  SPHINCTER  ANI  EXTERNUS. 

§ 2183.  The  sphincter  ani  ext  emus  muscle  is  much  stronger  than 
the  preceding,  and  although  a distinct  muscle,  exactly  surrounds  it. 
It  is  situated  under  the  skin,  to  which  it  adheres  very  intimately.  It 
is  thin  and  flat  ; its  internal  fibres  are  less  arched  than  the  external,  and 
the  anterior  and  the  posterior  unite  at  an  acute  angle.  Its  anterior 
and  posterior  extremities  are  pointed. 

The  posterior  extremity  is  attached  to  the  posterior  face  of  the  last 
piece  of  the  coccyx  either  directly  or  by  a compact  cellular  tissué. 

The  anterior  blends  with  the  transversus  perinei  muscle,  and 
usually  also  in  man  with  the  posterior  extremity  of  the  bulbo-caver- 
nosus,  in  the  female  with  the  constrictor  vaginæ  muscle.  But  some- 
times also  it  terminates  in  the  perineum,  either  by  fleshy  or  by  tendi- 
nous fibres,  and  does  not  extend  to  either  of  these  two  muscles. 


(1)  Galeati,  loc.  cit.,  fig.  3. 


OF  THE  DIGESTIVE  SYSTEM. 


277 


In  the  male  it  is  more  oblong,  and  its  greatest  diameter  extends 
from  before  backward  ; in  the  female  it  is  more  circular,  and  at  its 
anterior  part  it  is  broader  and  stronger.  These  differences  undoubtedly 
depend  on  those  which  exist  in  the  two  sexes  in  the  form  of  the  pelvis 
and  the  external  organs  of  generation. 

G.  FONCTIONS  OF  THE  LARGE  INTESTINE. 

§ 2184.  The  large  intestine  absorbs  the  small  quantity  of  nutritious 
substance  still  contained  in  its  contents,  and  sends  the  rest  toward  the 
anus.  In  this  course  the  feces  gradually  become  harder  and  more 
solid.  The  action  of  the  muscular  membrane  finally  expels  them, 
overcoming  the  resistance  of  the  sphincters  with  or  without  the  con» 
currence  of  the  will.  This  expulsion  always  occurs  periodically. 

B.  DIFFERENCES  DEPENDING  ON  DEVELOPMENT. 

§ 2185.  Of  all  the  parts  in  the  abdominal  cavity  the  intestinal  canal 
is  formed  first  ; its  mode  of  development  and  the  changes  in  its  situa» 
tion,  form,  and  volume,  present  equally  remarkable  phenomena.(l) 

A.  MODE  OF  DEVELOPMENT. 

§ 2186.  In  respect  to  the  mode  of  development  one  part  is  most  in- 
timately connected  with  the  formation  of  the  whole  fetus,  but  particu- 
larly with  that  of  the  intestinal  canal,  and  must  consequently  be  men- 
tioned first  : we  mean  the  umbilical  vesicle  (vtsicula  intestinalis , s. 
umbilicalis).  It  is  a small,  more  or  less  rounded  pouch,  situated  be- 
tween the  chorion  and  the  amnion,  and  is  probably  much  larger  in 
proportion  to  the  fetus  the  more  recent  the  period  of  conception.  It  is 
even  greater  than  the  fetus  during  the  early  periods  of  gestation,  and 
we  have  reason  to  think  that  it  is  always  formed  before  it.  It  extends 
first  to  the  anterior  face  of  the  body  of  the  fetus,  which  rests  directly 
upon  it.  But  gradually  and  even  early  in  the  first  month  of  gesta- 


tt) C.  P.  Wolff,  Deformations  intestinorum  ; in  N.  C.  Petrop,  voL  xii.,  p.  1768. — 
Oken,  Anatomisch-physiologische  Untersuchungen , angestellt  an  Schweinsfötus , 
Schweinsembryonen  und  Hundsembryonen  zur  Losung  des  Problems  über  das  Na- 
betblàschen,  &c.,  in  Oken  and  Kieser,  Heytragen , Hamburgh,  1806,  1807. — J.  F. 
Meckel,  Abhandlungen  aus  der  menschlichen  und  vergleichenden  Anatomie , Halle, 
1806. — Id.,  Bcyträgen  zur  vergleichenden  Anatomie , Halle,  1808,  vol.  i.,  pt.  i.,  no.  5. 
— Id.,  Ueber  die  Divertikel,  in  Keil,  Archiv,  für  die  Physiologie,  vol.  ix. — D.  Kieser, 
Der  Ursprung  des  Darmkanas  aus  dem  Nabclblàschen,  Gottingen,  1810. — Hoech- 
stetter and  Emmer*,  Ueber  das  Nabclblàschen  ; in  Reil,  Archiv,  für  die  Physiologie , 
vol.  x. — Fleischmann,  Leichenöffnungen,  Erlangen,  1815,  p.  i— 75. — J.  F.  Meckel, 
Sur  la  formation  du  canal  intestinal  dans  les  mammifères  et  en  particulier  dans 
l’homme;  in  the  Journ.  compl.  du  diet,  des  sc.  méd.,  vol.  ii.,  p.  119  and  289. — L. 
Rolando,  Sur  la  formation  du  canal  alimentaire  et  des  viscères  qui  en  dépendent  ; 
in  the  Journ.  compl.  des  sc.  méd.,  vol.  xvi.,  p.  53. 

Vol,  ILL  3G 


278 


DESCRIPTIVE  ANATOMY. 


tion,  it  diminishes  much,  end  is  situated  farther  from  the  fetus,  so  that 
in  the  second  month  it  is  on  the  outside  of  the  umbilical  cord. 

Do  the  parietes  of  the  umbilical  vesicle  and  the  intestinal  canal  pri- 
mitively communicate  ? Several  anatomists  of  great  merit(l)  think 
that  this  communication  is  demonstrated  neither  in  ihe  fetuses  of  the 
mammalia  generally  nor  in  that  of  man  in  particular.  The  following 
facts,  however,  render  this  opinion  very  probable  : 

1st.  The  analogy  with  birds,  reptiles,  and  cartilaginous  fishes,  to 
the  vitelline  membrane  of  which  the  umbillical  vesicle  corresponds 
perfectly, (2)  and  in  which  it  is  proved  that  the  communication  in  dis- 
pute exists  at  all  periods  of  fetal  existence. 

2d.  We  sometimes  perceive  in  very  young  fetuses  a canal  which 
goes  across  the  umbilical  sheath,  from  the  vesicle  to  the  abdomen,  and 
by  which  we  can  at  pleasure  empty  the  vesicle  of  this  fluid,  and  fill  it 
again.(3) 

3d.  We  always  find  in  the  fetus,  until  the  commencement  of  the 
fourth  month,  blood  vessels  which  go  from  the  mesentery  to  the  um- 
bilical vesicle,  unite  first  on  this  latter,  but  gradually  extend  only  to 
the  anterior  wall  of  the  abdomen,  and  finally  die,  and  are  ruptured  or 
entirely  effaced.  These  are  the  omphalomesenteric  vessels  (rasa  om- 
phalo-mesaraica),  comprehending  an  artery  and  a vein,  which  arise 
from  the  mesenteric  vessels. (4) 

These  vessels  also  exist  in  birds,  where  they  go  to  the  yolk,  pro- 
ceeding along  the  vitelline  canal. 

4th.  The  intestines  are  at  first  very  near  the  umbilical  vesicle,  and 
are  situated  out  of  the  abdomen  in  the  umbilical  sheath,  which  at  this 
period  really  makes  part  of  the  abdominal  cavity. (5) 

It  is  not  unfrequent,  proportionally  speaking,  to  find  in  the  full  grown 
fetus  a canal  which  extends  from  the  intestine  to  the  umbilicus,  which 
opens  in  this  latter  place,  and  is  always  attended  by  the  omphalo- 
mesenteric vessels.(6.) 

It  is  then  very  probable,  though  not  certain,  from  all  these  facts,  that 
the  umbilical  vesicle  and  the  intestinal  canal  originally  communicate. 
There  are,  however,  others  which  really  demonstrate  the  existence  of 
this  communication. 

Thus  we  have  mentioned  above  a human  fetus  five  lines  long,  in 
which  we  saw  distinctly  a filament  attached  to  the  umbilical  vesicle 

(1)  Emmert.— Hoesclistetter.— Cuvier,  Ann.  du  Museum , vol.  iii. 

(2)  Needham,  De  form,  fœtu,  London,  1667,  p.  79. — Blumenbach,  Spec.  phys. 
comp,  inter  anim.  cal.  sang.  ov.  et  viv.,  Gottingen,  1739,  p.  11.— Sœmmerring-,  in 
Haller,  Grundriss  der  Physiologie,  vol.  ii.,  p.  799,  800. 

(3)  Hunter,  Anatomische  Beschreibung  des  schwang.  Uterus,  p.  68. 

(4)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  i.,  p.  563. — We  have 
since  verified  this  remark  in  at  least  ten  fetuses  of  this  age. 

(5)  Meckel,  Abhandlungen,  1806,  p.  301.— Oken,  Beytràge,  1806,  ch.  ix. 

(6)  We  have  collected,  in  the  first  volume  of  our  Hand,  der  Path.  Anatomie,  all 
the  known  cases  of  this  anomaly,  one  of  which  wc  observed  and  described  (Reil, 
Archiv,  für  die  Physiologie , vol.  ix). 


OF  THE  DIGESTIVE  SYSTEM. 


279 


and  extended  to  the  intestine,  and  we  have  figured  this  communication 
as  it  exists  in  fetuses  of  sheep  and  cows,(l)  since  admitted  by  Bojanus 
also  in  the  fetuses  of  sheep.(l) 

Men,  however,  of  high  authority,  doubt  it.  Emmert,  Hcechstetter, 
and  Cuvier,  assert  that  there  is  no  continuity  of  substance  between  the 
two  organs,  and  that  the  communication  existing  between  them,  is  es- 
tablished only  by  the  omphalo-mesenteric  vessels.  In  fact,  they  admit, 
beside  these  vessels,  a third  filament,  extended  between  the  vesicle  and 
the  intestine,  but  they  do  not  consider  it  as  a canal  of  union,  but  only 
as  a simple  prolongation  of  the  peritoneum.  The  following  are  the  ar- 
guments in  support  of  their  opinions  : 

1st.  The  impossibility  of  passing  water  or  any  other  fluid  from  the 
vesicle  into  the  intestinal  canal. (3) 

2d.  The  great  difference  between  the  white  and  thick  substance  of 
the  alimentary  canal,  and  the  thin  reddish  membrane  of  the  vesicle,  and 
also  the  pellucid  and  delicate  membrane  which  unites  these  two  or- 
gans, and  accompanies  the  omphalo-mesenteric  vessels. (5) 

But  we  may  reply  to  the  first  objection,  that  the  phenomenon  on 
which  it  rests  depends  perhaps  on  the  narrowness  of  the  canal,  and 
also  on  the  thinness  of  the  vesicle,  and  demonstrates  at  most  the  ab- 
sence of  a hollow  canal  of  communication,  the  admission  of  which  i3 
not  absolutely  necessary,  since  the  intestinal  canal  of  several  animals 
is  solid  at  intervals,  in  the  normal  state. 

The  second  objection  also  loses  its  weight,  when  we  consider  that 
the  allantoid  membrane  and  the  urachus  vary  at  least  as  much  from  the 
bladder,  and  we  observe  as  great,  or  even  greater  constant  differences 
between  different  parts  of  the  same  system.  This  remark  is  more  rea- 
sonable, since  we  have  found  the  opening  of  the  communication  great- 
est in  sharks,  where  the  differences  between  the  vitelline  membrane 
and  the  intestinal  canal  were  most  distinct.  Farther,  the  differences 
are  also  considerable  in  the  cases  last  mentioned. 

We  think  then  that  we  must  at  present  admit  a continuity  of  sub- 
stance between  the  umbilical  vesicle  and  the  intestinal  canal,  without 
pretending  to  decide  if  the  cavities  of  the  two  organs  open  into  each 
other. 

From  the  analogy  of  the  development  of  the  intestinal  canal  in  the 
fetuses  of  birds,  this  canal  is  formed  in  the  following  manner.  The 
vitelline  membrane,  which  is  at  first  in  direct  contact  with  the  vertebral 
column,  begins  by  forming  a small  prominence  on  each  side,  so  that 
originally,  the  intestine,  which  has  the  form  of  a groove,  opens  anteriorly. 

(1)  Muller,  De  genitalium  evolutione,  Halle,  1815,  fig-.  1-2,  p.  11. 

(2)  Sur  la  vésicule  ombilicale  du  fœtus  de  brebis  ; in  the  Journ.  compl.  du  diet,  des 
sc.  méd .,  vol.  ii.,  p.  84. — Dutrochet,  Recherches  sur  les  enveloppes  du  fœtus  ; in  the 
Mem.  de  la  soc.  méd.  d’émulation  de  Paris , 1816;  and  a note  to  the  Réflexions  du 
professeur  Emmert  sur  la  vésicule  ombilicale , in  the  Journ.  compl.  des  sc.  méd,,  vol. 
ii.,  p.  369. 

(3)  Emmert,  in  Reil,  Archiv  für  die  Physiologie , vol.  x.  p.  52. 

(4)  Emmert,  loc.  cit.,  p.  75. 


280 


DESCRIPTIVE  ANATOMY. 


This  groove  gradually  forms,  by  the  increase  of  its  parietes,  from  be- 
hind forward,  from  above  downward,  and  from  below  upward,  to  the 
place  where  the  cavity  of  the  intestine  communicates  with  the  vitelline 
sac  by  the  vitelline  canal,  the  diameter  of  which  always  diminishes.(l) 
Oken’s  opinion,  that  the  intestinal  canal  should  be  considered  as  a kind 
of  excrescence  of  the  umbilical  vesicle,  which  enters  already  formed 
into  the  abdomen  from  above  and  from  below,  is  less  probable,  and  is 
unsupported  by  facts. 

§ 21S7.  Does  the  intestinal  canal  always  communicate  with  the 
umbilical  vesicle  in  one  determinate  point  ? What  is  this  point  1 

First,  this  canal  is  continuous  with  the  vesicle  by  its  anterior  edge, 
but  very  probably  the  point  to  which  the  communication  is  finally  con- 
fined, always  corresponds  to  a determinate  place,  although  it  may  vary 
in  a certain  extent. 

Two  such  points  have  been  mentioned.  Oken  thinks  it  is  the  point 
of  union  between  the  large  and  small  intestine.  He  considers  the  ver- 
miform appendix  and  the  cæcum  as  the  result  and  the  remains  of  this 
communication. (2)  In  this  view  of  the  subject,  the  umbilical  vesicle  in 
collapsing,  and  the  intestinal  canal  on  descending  deeply  into  the  ab- 
domen, produce  a contraction,  a kind  of  neck,  the  parietes  of  which  ap- 
proach, and  are  finally  blended.  This  separates  the  intestine  from  the 
umbilical  vesicle.  The  canal  then  enters  into  the  abdominal  cavity, 
where  the  situation  of  the  intestines,  hitherto  parallel,  necessarily 
changes,  so  that  the  anterior  joins  the  neck  at  an  angle,  and  the 
neck  becomes  a prolongation  of  the  posterior,  which  preserves  its 
former  direction.  Hence,  according  to  Oken,  the  upper  intestine  seems 
to  penetrate  into  the  lower,  the  angle  of  union  becomes  the  ileo-ccecal 
valve,  and  the  neck  gives  rise  to  the  cæcum  and  iis  vermiform  appen- 
dix. But, 

1st.  We  do  not  see  why  the  contraction  of  the  intestine,  and  their 
entrance  into  the  abdomen,  necessarily  result  in  causing  the  upper  part 
of  the  intestine  to  enter  into  the  lower,  and  form  a vermiform  appendix. 
This  is  still  less  probable,  inasmuch  as  the  cæcum  and  the  ileo-colic 
valve  are  rarely  deficient  in  man  from  a primitive  deviation  of  formation, 
while  they  are  normally  absent  in  many  mammalia  provided  with  an 
umbilical  vesicle  ; while  others,  in  whom  the  cæcum  is  very  large, 
have  no  vesicle.  The  great  differences  in  the  length  and  structure  of 
the  cæcum,  render  Oken’s  opinion  very  improbable.  It  is  even  more 
probable,  on  the  contrary,  that  the  consecprence  of  such  a formation 
would  be  a simple  uninterrutped  canal. 

(1)  Wolff  demonstrated  long  since  the  manner  in  which  the  intestinal  canal  was 
formed  by  the  vitelline  membrane,  in  birds,  after  very  correct  and  careful  observa- 
tions, made  at  an  useful  time,  that  is,  at  a period  very  near  its  first  formation. 
As  Needham,  Blumenbach,  and  Sœmmcrring,  have  demonstrated  the  identity  of 
the  vitelline  envelop  and  the  umbilical  vesicle,  Oken  had  no  right  to  claim,  as  he  has 
done  ( Beytragen  zur  vergleichenden  Anatomie , 1806. — Lehrbuch  der  Naturges- 
chichte, 1815,  p.  3),  the  honor  of  having  discovered  in  the  envelops  of  the  fetus  of  the 
hog,  that  the  intestinal  canal  is  formed  from  the  umbilical  vesicle. 

(2)  Loc.  cit.,  part  ii.  p.  85. 


OF  THE  DIGESTIVE  SYSTEM. 


281 


2d.  The  cause  to  which  Oken  attributes  this  change  does  not  exist; 
for  the  cæcum  is  formed  long  before  the  intestines  pass  into  the  abdo- 
men, and  is  itself  inclosed  in  the  umbilical  sheath. 

3d.  If  the  cæcum  was  the  point  where  the  intestine  was  detached 
from  the  umbilical  vesicle,  it  would  also  be  the  most  anterior  part  of  the 
intestinal  canal,  and  the  nearest  to  the  vesicle.  But  this  never  occurs, 
for  we  always  find  a fold  of  the  small  intestine  before  the  vermiform 
appendix.  Oken,  it  is  true,  has  figured  the  contrary,  according. to  his 
idea,  that  in  man  the  intestines  must  detach  themselves  from  the  um- 
bilical vesicle, (1)  but  unfortunately  this  does  not  exist  in  nature. 

§ 2188.  Oken’s  opinion  is  still  less  admissible,  since  arguments  unite 
to  render  it  very  probable,  that  the  communication  between  the  intes- 
tine and  the  umbilical  vesicle  always  exists  in  a determinate,  but  very 
different  place  from  that  mentioned  by  him.  This  place  is  in  the  small 
intestine,  and  nearer  its  lower  than  its  upper  extremity. 

The  arguments  in  support  of  this  second  opinion,  all  of  which  are 
opposed  to  the  theory  of  Oken,  are  the  following  : 

1st.  The  canals  between  the  intestine  and  the  anterior  wrall  of  the 
abdomen,  always  proceed  from  this  point. 

2d.  In  one  rare  case,  in  a full  grown  fetus,  monstrous  from  the  deve- 
lopment being  arrested  at  several  times,  there  w'as  a real  umbilical 
vesicle  inserted  in  this  canal. (2) 

3d.  In  this  part  of  the  canal,  the  vitelline  canal  in  birds  and  reptiles 
terminates. 

4th.  We  find  as  the  normal  formation  in  most  birds,  and  perhaps 
also  in  some  mammalia,  and  not  unfrequentiy  as  an  anomaly,  in  this 
part,  and  never  in  any  other,  in  man  and  other  mammalia,  a single 
rounded  prolongation,  varying  in  length  and  breadth,  and  surrounded 
by  the  same  membranes.  This  prolongation,  termed  the  diverticulum,  is 
evidently  a trace  of  the  primitive  canal  of  communication  ; it  is  fre- 
quently attended  both  in  the  fetus  and  adult,  with  the  remains  of  the 
omphalo-mesenteric  vessels. 

Very  probably,  there  is  a period  in  the  existence  of  the  human  fetus, 
when  a similar  small  tubercle  exists  regularly,  after  the  umbilical 
vesicle  is  separated  from  the  intestine.  Having  found  a very  large  di- 
verticulum attended  by  the  omphalo-mesenteric  vessels  in  four  human 
fetuses  three  months  old,  which  we  had  occasion  to  examine  at  nearly 
the  same  time,  we  have  reason  to  think  that  the  appendix  continues 
regularly  until  this  period,  that  is,  long  after  the  intestinal  canal  ha3 
entered  the  abdomen. (3)  But  we  now  renounce  this  opinion,  although 
it  has  been  refuted  by  no  one.  If  a diverticulum  really  exist  for  some 
time  as  a normal  formation,  it  disappears  long  before  the  end  of  the 
third  month  of  gestation,  since  we  have  seen  the  cæcum  in  the  seventh 
week,  although  there  was  no  trace  of  a diverticulum;  whence  it  follows, 

(1)  Loe.  cit.,  p.  84.  vol.  iv.  fig1 2 3.  14. 

(2)  Tiedemann,  Anatomie  der  kopflosen  Missgeburten , tab.  iv. 

(3)  Handbuch  der  pathologischen  Anatomie,  vol.  i.  p.  565. 


282 


DESCT iPTIVE  ANATOMT. 


that  the  omplialo-mesenteiic  vessels  continue  much  longer  than  it. 
But  this  circumstance  does  not  prove  that  the  diverticulum  never  exists 
normally,  or  that  Oken’s  opinion  of  the  cæcum  is  correct. 

5th.  This  is  the  point  whence  the  omphalo-mesenteric  vessels  depart 
to  go  into  the  umbilical  sheath,  after,  and  even  before  the  intestines 
have  entered  the  abdomen. 

6th.  In  all  these  cases  one  or  two  normal  cæcums  always  exist  in 
the  part  where  the  large  intestine  unites  with  the  small. 

These  different  arguments  seem  to  us  to  render  the  insertion  of  the 
umbilical  vessels  on  the  ileon  much  more  probable  than  that  of  this 
organ,  in  the  point  mentioned  by  Oken.  The  diverticulum  sometimes 
found,  depends  either  on  an  abnormal  want  of  energy  in  the  formative 
power,  or  on  the  fact,  that  the  neck  of  the  umbilical  vesicle,  which  per- 
haps commonly  dies  on  the  surface  of  the  intestine,  does  not  then  dis- 
appear except  in  a greater  or  less  extent. 

Although  these  arguments  were  published  long  since,  Oken  still 
continues  to  maintain  that  the  cæcum  is  the  part  where  the  intestinal 
canal  is  detached  from  the  umbilical  vesicle,(l)  and  he  lays  it  down  as 
a principle  either  to  oppose  us,  or  to  support  his  opinion:  1st,  that 
there  is  never  but  one  cæcum  ; 2d,  that  the  cæcums  of  birds  do 
not  deserve  this  name,  and  are  only  appendages  of  the  bladder  ; 3d, 
that  the  cæcum  exists  in  all  mammalia,  and  in  all  birds  and  fishes  who 
lay  large  eggs,  while  it  is  so  small  as  to  be  invisible  in  a very  few  of 
these  animals,  the  eggs  of  which  are  small  ;(2)  4th,  that  this  organ  is 
the  old  vitelline  canal.  As  these  assertions  are  published  in  an  ele- 
mentary work,  they  deserve  to  be  examined,  although  it  is  easily  seen 
that  they  are  totally  unfounded. 

In  establishing  his  four  laws,  Oken  has  forgotten,  1st,  of  those 
mammalia  which  possess  two  cæcums,  as  the  dama  and  the  phasco- 
lomys  ; 2d,  the  coexistence  of  the  canal  of  the  .umbilical  vesicle,  the  di- 
verticulum, and  the  cæcum,  in  the  mammalia  and  birds  ; 3d,  the  per- 
fect resemblance  in  the  mammalia  and  birds,  in  the  relations  between 
the  cæcums,  the  vitelline  canal,  the  diverticulum,  and  the  rest  of  the 
intestinal  canal,  since  the  cæcums  always  exist  on  the  limit  between 
the  large  and  the  small  intestine,  while  this  is  never  true  of  the  canal 
and  the  diverticulum  ; 4th,  the  absolute  want  of  facts,  establishing  that 
the  intestinal  canal  unites  with  the  vesicle  by  the  cæcum,  while  there 
are  a great  number  proving  that  it  always  occurs  near  the  lower  part 
of  the  small  intestine  ; 5th,  the  fact  that  the  volume  has  no  effect  on 
the  deficiency  of  the  large  or  small  size,  and  the  other  conditions  of 
the  cæcum,  since  it  is  very  large  in  most  mammalia,  and  is  entirely  de- 
ficient in  many  birds.  Even  when  we  admit  that  the  diverticulum  of 
birds  is  the  cæcum,  which,  however,  is  impossible,  his  third  law  would 
still  be  refuted.  His  third  remark,  “ that  the  cæcum  exists  in  all  mam- 

(1)  Zoologie,  1815,  vol.  i.  p.  2. 

(2)  Loc.  cit.,  p.  10. 


OP  THE  DIGESTIVE  SYSTEM. 


283 


malia,  &c.,  but  it  is  so  small,  as  to  be  invisible  in  a very  few  of  these 
animals,”  is  difficult  to  understand. 

Oken  has  also  brought  forward  in  favor  of  his  hypothesis  : 

1st.  The  arrangement  of  the  cæcums  in  fishes,  in  which  the  vitel- 
line sac  of  the  superior  animals  is  divided  into  several  culs-de-sac. 

2d.  The  formation  of  the  chondropterygia,(l)  in  which  the  cæcum 
arises  distinctly  from  the  vitelline  sac. 

One  cannot  suppose  that  he  himself  believes  these  two  arguments 
to  be  valid  : for 

1st.  Comparative  anatomy  demonstrates  most  positively,  that  the 
cæcums  of  fishes  are  pancreatic  glands,  and  no  one  has  hitherto  at- 
tempted to  compare  them  to  the  vitelline  membrane,  which  also  exists 
in  these  animals. 

2d.  The  cæcum  of  the  chondropterygia  is  found  at  the  end  of  the 
large  intestine,  and  the  vitelline  canal  at  the  end  of  the  small  intestine. 

3d.  The  vitelline  canal  is  broadly  open  in  the  fetus,  and  exists  at  the 
same  time  as  the  cæcum,  and  is  entirely  separate  from  it.  This  latter 
continues  during  life,  while  the  canal  entirely  disappears. 

We  then  have  cause  to  retain  our  opinion,  as  it  is  also  supported  by 
respectable  authorities,  as  Tiedemann, (2)  Cuvier,  (3)  Dutrochet,(4) 
and  Jæger.(5) 


B.  SITUATION. 

§ 2189.  The  situation  of  the  intestinal  canal  varies  at  different 
periods,  as  one  may  conclude  from  the  details  already  mentioned.  Al- 
though it  forms  on  the  anterior  face  of  the  vertebral  column,  it  is,  how- 
ever, generally  further  from  it  in  most  of  its  extent,  during  the  early 
periods  of  existence  than  subsequently.  At  first  only  a small  portion 
of  its  upper  and  lower  extremities  exist  in  the  proper  abdominal  cavity  ; 
all  the  rest  is  inclosed  in  the  umbilical  sheath,  which  for  this  or  for 
other  reasons,  is  then  extremely  large,  and  should  be  considered  as  a 
prolongation  of  the  abdomen.  At  first  the  upper  and  lower  extremities 
of  the  intestinal  canal  extend  in  a straight  line,  side  by  side,  and  de- 
scribe an  angle  to  communicate  together;  but  gradually,  at  the 
seventh  week  of  gestation,  they  proceed  backward,  begin  to  become 
tortuous,  and  reunite  in  a fold  before  the  umbilical  opening,  Only  the 
small  intestine  is  tortuous,  the  large  intestine  is  perfectly  straight,  and 
its  blunt  extremity,  the  cæcum,  goes  forward,  but  always  far  behind 
the  anterior  extremity  of  the  small  intestine. 

About  the  middle  of  the  third  month,  the  intestinal  canal  enters  en- 
tirely into  the  cavity  of  the  abdomen,  where  the  lower  part  of  the  small 

(1)  Isis , 1818,  p.  20. 

(2)  Anatomie  der  kopflosen  Missgeburten,  p.  66. 

(3)  Isis,  1818,  p.  138. 

(4)  Loc.  cit. 

(5)  Deutsches  Archiv  für  die  Physiologie , vol.  iii.  p.  543. 


284 


DESCRIPTIVE  ANATOMY. 


intestine  is  the  last  to  proceed.  At  this  period,  and  sometime  after,  the 
canal,  especially  the  large  intestine,  varies  as  much  as  before  from  the 
arrangement  it  will  afterwards  normally  possess.  In  fact,  the  large 
intestine  is  not  formed  of  three  portions,  two  lateral,  which  are  perpen- 
dicular, and  a middle  transverse  portion,  the  right  of  which  is  attached 
to  the  organs  behind  it  only  by  a short  fold  of  the  peritoneum  ; but  it  is 
formed  at  first  by  a single  perpendicular  portion,  attached  by  a long 
mesentery,  to  the  centre  of  the  posterior  wall  of  the  abdomen.  This 
portion  is  gradually  reflected  from  right  to  left  at  its  summit  ; it  then 
descends  on  the  right,  so  that  the  union  of  the  great  and  small  intes- 
tine does  not  correspond  to  the  right  lumbar  region  until  toward  the 
end  of  the  fourth  month.  For  a long  time,  and  until  birth,  the  de- 
scending colon  describes  in  the  left  iliac  region,  a greater  curve  than  it 
does  in  the  adult,  which  undoubtedly  depends  on  the  narrowness  of  the 
pelvis. 

The  situation  of  the  stomach  differs  primitively  from  that  assumed 
by  it  in  the  adult,  as  it  is  at  first  almost  perpendicular.  The  duode- 
num is  detached  from  it,  and  goes  directly  downward  and  forward 
without  any  curve.  When  the  liver  diminishes  in  size,  and  the  intes- 
tines enter  the  abdomen,  the  stomach  and  the  duodenum  gradually 
change  their  situation,  and  assume  that  which  they  afterward  retain. 

C.  DIMENSIONS. 

§ 2190.  The  intestinal  canal  is  much  shorter  and  narrower  the 
younger  the  fetus  is.  At  first  it  is  no  longer  than  the  vertebral  column, 
on  the  anterior  face  of  which  it  is  developed.  It  then  becomes  more 
extensive,  and  extends  always  in  a straight  line  into  the  umbilical 
sheath,  but  when  it  becomes  longer,  it  is  tortuous,  being  situated  in  a 
narrow  space. 

The  small  is  much  broader  in  proportion  to  the  large  intestine,  the 
younger  the  fetus  is.  In  this  respect,  the  relation  between  them  is  op- 
posite to  that  which  exists  in  the  adult,  for  the  small  intestine,  for  a 
long  time,  is  much  greater  than  the  large,  and  even  in  the  full  grown 
fetus  the  latter  is  frequently  not  at  all  or  but  little  broader  than  it. 

On  the  other  hand,  the  large  intestine  is  much  longer  in  proportion 
to  the  small,  the  younger  the  fetus  is.  This  difference  undoubtedly 
depends  on  the  fact,  that  the  small  intestine  is  much  shorter  in  propor- 
tion to  the  body  in  the  early  periods  than  in  the  adult. 

The  cæcum  and  the  vermiform  process  are  at  first  very  small,  but 
soon  increase  considerably,  so  that  they  are  proportionally  much  larger 
and  broader  than  they  are  subsequently.  They  are  not  originally 
separated  in  the  same  manner  as  in  the  adult;  the  cæcum  is  not  en- 
larged before  it  is  continuous  with  its  appendix;  the  latter  is  not  as  nar- 
row, but  represents  the  extremity  of  the  large  intestine,  which  is  ex- 
tended in  a cul-de-sac  above  the  ileon,  gradually  contracting  a little  on 
itself. 


OP  THE  DIGESTIVE  SYSTEM. 


285 


As  the  cæcum  first  appears  in  man,  the  mammalia,  and  birds,  as  a 
small  tubercle,  which  gradually  enlarges,  and  of  which  there  is  not 
the  least  trace  at  first,  this  circumstance  alone  demonstrates  that  it  is 
not  formed  in  the  manner  mentioned  by  Oken,  but  by  an  enlargement 
of  the  large'  intestine.  Before  it  appears,  there  is  no  mark  of  difference 
between  the  large  and  the  small  intestine.  The  ileo-colic  valve  is  at 
first  imperfect  and  very  small  ; it  however  begins  to  appear  at  the 
third  month  of  gestation,  and  it  is  perfectly  developed  in  the  full  grown 
fetus. 

D.  FORM. 

§ 2191.  The  intestinal  canal  during  its  development,  differs  con- 
siderably in  its  form,  and  in  the  arrangement  of  its  membranes. 

We  have  already  mentioned  the  differences  which  occur  in  the 
cæcum,  when  speaking  of  those  in  dimension.  We  must  add  the 
following  remarks  : 

1st.  The  stomach  is  at  first  much  longer  and  more  rounded  than 
when  the  development  is  completed.  The  great  cul-de-sac  does  not 
exist  originally,  and  it  afterwards  is  larger  than  in  the  adult. 

2d.  The  outer  face  of  the  large  intestine  is  perfectly  smooth  until  to- 
ward the  end  of  the  fifth  month.  The  enlargements,  which  are  the 
sources  of  its  great  size,  appear  first  in  the  transverse  colon. 

Of  the  intestinal  tunics,  the  internal  particularly  presents  differences 
relative  to  the  development  of  the  organ. 

1st.  It  is  more  uniform  in  the  different  regions  of  the  intestinal  canal 
during  the  early  periods  of  life  than  subsequently.  Of  this  we  may  be 
easily  convinced  by  examining  the  valvules  or  the  villosities. 

а.  The  villosities  do  not  appear  before  the  third  month  of  gestation. 
At  this  time  they  are  seen  first  along  the  whole  intestinal  canal,  in  the 
form  of  longitudinal  folds,  the  surface  of  which  is  indented,  and  which, 
like  the  indentations,  gradually  increase  in  number.  Such  is  the  origin 
of  the  villosities.  When  they  are  developed  in  this  manner,  they  exist 
also  in  the  large  intestine  till  the  seventh  month  of  gestation,  although 
their  length  is  less  at  three  months  than  in  the  small  intestine,  and  it 
diminishes,  as  well  as  their  number,  from  month  to  month,  in  which 
respect,  the  two  regions  of  the  intestinal  canal  are  at  first  perfectly 
similar. 

б.  The  valvules  of  the  jejunum  do  not  exist  until  the  seventh  month  ; 
they  are  even  in  the  full  grown  fetus  but  slightly  prominent,  and  easily 
effaced  by  compression. 

These  two  peculiarities  are  curious,  as  they  are  analogous  to  what 
occurs  in  animals. 

2d.  The  inner  membrane  of  the  stomach  is  thicker,  and  more  easily 
separated  from  the  others  in  the  early  periods  of  fetal  existence  than 
subsequently  ; it  is  less  easy  to  insulate  it  entirely  in  the  form  of  a per- 
fect sac. 


VOL.  Ill 


37 


286 


DESCRIPTIVE  ANATOMY. 


ARTICLE  THIRD. 

INTESTINAL  CANAL  IN  THE  ABNORMAL  STATE. 

§ 2192.  The  abdominal  portion  of  the  alimentary  canal  presents 
numerous  anomalies  in  its  form  and  texture.(l) 

I.  DEVIATIONS  OF  FORMATION. 

A.  PRIMITIVE  DEVIATIONS  OF  FORMATION. 

§ 2193.  The  primitive  deviations  of  formation  belong  principally  to 
the  class  of  those  which  affect  the  quantity. 

Among  those  of  the  first  class,  which  essentially  consist  in  an  im- 
perfect development  of  the  formative  power,  or  a continuance  in  the 
peculiar  type  of  the  fetus,  may  be  arranged  the  following,  some  of 
which  certainly  belong  to  this  class,  and  others  may  probably  be 
arranged  in  it. 

I.  GENERAL  DEVIATIONS, 

1st.  Absence.  This  deviation  of  formation  relates  principally  : 

a To  the  stomach,  especially  in  acephalia  vera,  where  the  intestinal 
canal  generally  terminates  in  a cul-de-sac  at  its  upper  part,  and  is  sel- 
dom enlarged.  Sometimes  a portion  of  the  stomach  also  is  deficient, 
particularly  the  pyloric  valve,  which  is  wholly  or  partially  absent.(2) 

b.  To  the  smalt  intestine.  It  is  deficient,  wholly  or  partially,  in  ace- 
phalia vera,  in  which  we  often  observe  that  the  large  intestine,  or  only 
the  lower  part  of  the  small  intestine  exists. 

c.  To  the  vermiform  appendix,  which  is  sometimes,  though  rarely, 
deficient,  even  when  the  rest  of  the  canal  is  not  abnormal. 

d.  To  the  ileo  colic  valve,  which  is  then  simply  replaced  by  some 
strong  muscular  fibres. 

e.  To  the  large  intestine.  Here  the  anomaly  exists  in  several  de- 
grees, which  are  commonly  attended  with  an  imperforate  anus, 

(1)  A.  Monro,  The  morbid  anatomy  of  the  human  gullet,  stomach,  and  intestines , 
Edinburgh,  1811. — A.  D.  Stone,  A practical  treatise  on  the  diseases  of  the  stomach, 
and  of  digestion.  London,  1816. — T.  A.  Hare,  View  of  the  structure,  functions,  and 
disorders  of  the  stomach  and  alimentary  organs  of  the  human  body,  London,  1821. 
— G.  Law,  Observations  on  derangements  of  the  digestive  organs,  and  some  views 
of  their  connection  with  local  complaints , Edinburgh,  1821. — Scoutetten,  De  l’ana- 
tomie pathologique  en  général  et  de  celle  du  canal  digestif  en  particulier,  Paris, 

1822.  — Andra),  Recherches  sur  l’anatomie  pathologique  du  canal  digestif,  Paris, 

1823. 

(2)  Fleischmann,  Lcichcnôjfungcn,  p.  100-102, 


OF  THE  DIGESTIVE  SYSTEM. 


287 


( atresia  ani),  because  it  usually  attends  this  last  deviation  of  forma- 
tion. 

Very  rarely  the  large  intestine  is  entirely  deficient,  existing  only  as 
a small  appendix  in  the  form  of  a cul-de-sac  of  the  small  intestine. 
Next  in  respect  to  frequency,  come  those  cases,  in  which  a small  por- 
tion of  the  large  intestine  is  deficient,  so  that  the  communication  be- 
tween the  large  and  small  intestine  is  uninterrupted;  finally,  that  where 
the  large  intestine  is  developed  to  the  entrance  of  the  pelvis,  but  where 
there  is  no  rectum.  Sometimes  the  rectum  partially  exists,  but  it  ter- 
minates in  a cul-de-sac,  and  the  space  between  it  and  the  lower  extre- 
mity of  the  colon  is  also  closed  in  a cul-de-sac. 

In  this  case  the  rectum  sometimes  opens  into  the  vagina  ( aircsia 
vaginalis ),  the  bladder  (a.  vesicalis),{  1)  or  the  urethra  (a.  urethralis),  so 
that  a real  cloaca  is  at  the  same  time  formed. 

2d.  Diminution  in  diameter.  This  anomaly  exists  in  several  de- 
grees ; in  the  greatest  degree  it  constitutes  imperforation  (a.  vera).  It 
is  always  attended  with  the  absence  of  a part,  since  on  account  of  this 
defect,  the  part  existing  terminates  in  a cul-de-sac. 

It  occurs  principally  in  the  anus,  where  it  varies  much  in  degree. 
Sometimes  the  opening  of  the  rectum  is  closed  only  by  a thin  mem- 
brane, sometimes  this  intestine  is  replaced  entirely  by  cellular  tissue,  or 
by  a full  and  solid  cord. 

Next  comes  the  large  intestine,  which  is  imperforate  at  a greater 
or  less  distance  above  the  anus.  The  ileon  and  colon  more  rarely  ter- 
minate in  a cul-de-sac. 

Still  more  rarely,  the  same  exists  in  the  small  intestine,  either  in  some 
part  of  its  course,  or  at  its  upper  extremity,  or  occurs  in  the  stomach, 
preventing  a communication  with  the  small  intestine,  or  finally  exists 
in  several  points  of  the  intestinal  canal. 

Strictures^)  ( a . spuria)  are  most  frequent  in  the  rectum  and  anus. 
They  seem,  however,  not  to  be  rare  in  the  stomach,  where  they  present 
remarkable  peculiarities.  In  this  case  the  stomach  is  most  generally 
divided  by  a contraction  near  its  centre,  into  two  sacs,  a right,  nar- 
rower and  more  elongated — a left,  larger  and  more  rounded.  The  upper 
part  of  the  left  sac  is  usually  not  concave,  but  very  convex,  and  the 
form  of  the  two  curves,  particularly  the  inferior,  are  very  much  en- 
larged, the  second  presenting  a deep  groove.  The  esophagus  is  al- 
ways inserted  at  the  usual  place,  and  the  cul-de-sac  is  never  enlarged. 
The  degree  of  contraction  varies  much,  from  half  an  inch  to  five  inches, 
judging  from  the  five  cases  now  before  us  ; but  the  right  half  of  the 
viscus  preserves  its  normal  direction.  However,  in  one  case  we  saw  it 
turned  on  its  axis,  so  that  the  convexity  looked  upward  and  forward, 

(1)  Cavenne,  Observation  d’une  imperforation  de  Vanus , avec  ouverture  de  l’intestin 
dans  la  vessie  ; in  the  Archiv,  gêner,  de  méd.,  vol.  v.  p.  63. — J.  G.  Hasselmann,  De 
ani  intestinirumque  atresia,  Utrecht,  1819. 

(2)  Boyer,  Remarques  et  observations  sur  quelques  maladies  de  Vanus,  in  Journ. 
compl.  des  sc.méd.,  vol.  ii.  p.  24. — G.  White,  Observations  on  strictures  of  the  rectum, 
Bath,  1820. 


288  DESCRIPTIVE  ANATOMY. 

and  the  concavity  downward  and  backward,  and  descended  here  before 
the  right  end  of  cardiac  half. 

More  rarely  the  stomach  is  divided  by  a second  contraction  into  three 
sacs,  of  which  the  third  undoubtedly  arises  from  an  unusual  separation 
of  the  cavity  of  the  pylorus  from  the  rest  of  the  cavity  of  the  organ. 

All  these  anomalies  are  curious,  as  analogous  with  animals.  They 
occur  principally  in  females. 

When  they  exist,  the  texture  of  the  stomach  is  unaltered  in  the  con- 
tracted portion.  This  circumstance,  however,  is  not  sufficient  to  justify 
the  opinion  mentioned  at  the  commencement  of  the  paragraph,  that 
this  state  constitutes  a primitive  deviation  of  formation,  and  farther,  be- 
cause, as  we  have  already  mentioned,  the  stomach  contracts  transiently 
at  the  same  place  during  digestion,  and  causes  of  different  kinds  might 
render  permanent  an  arrangement  which  should  be  transitory.  The 
greater  frequency  of  this  anomaly  in  females,  is  equally  favorable  to  the 
two  opinions.  We  then  have  reason  to  think  that  the  contraction  in 
question  does  not  always  occur  in  the  same  manner,  and  this  conjec- 
ture is  rendered  still  more  probable,  as  it  is  sometimes  congenital,  and 
attended  with  other  deviations  of  formation,  which  mark  an  arrest 
of  development^  1) 

Not  unfrequently,  from  a primitive  deviation  of  formation,  the  sto- 
mach is  no  larger  than  the  intestine,  in  which  case  it  cannot  be  di- 
lated. 

We  might  probably  mention  here  a valvular  contraction  of  the  left 
orifice  of  the  stomach,  which  is  very  curiously  attended  with  the  ab- 
sence of  the  pyloric  valve. (2)  If,  however,  this  anomaly  was  not  con- 
fined to  a simple  contraction,  we  ought  rather  to  refer  it  to  the  devia- 
tions of  formation  dependent  on  an  excess  of  the  formative  power. 

3d.  Shortness.  Occurring  sometimes  in  the  whole  of  the  intestinal 
canal,  but  most  frequently  in  the  vermiform  appendix  of  the  cæcum 
only. 

II.  SPECIAL  DEVIATIONS. 

§ 2194.  The  special  deviations  of  primitive  formation  are  : 

1st.  In  the  stomach. 

a.  The  absence  of  the  base,  which  we  have  once  observed  in  a 
child  two  months  old,  where  the  cul-de-sac  of  the  pylorus  was  much 
larger  than  that  of  the  cardia,  which  was  hardly  visible. 

b.  Its  perpendicular  situation,  which  does  not  always  depend  on  the 
abnormal  enlargement  of  the  liver,  or  on  any  other  mechanical  cause. 

2d.  In  the  intestinal  canal. 

a.  The  prolapsus  of  this  canal  into  the  umbilical  sheath  in  a case  of 
exomphalos.  Instances  of  this  anomaly  are  most  frequent  in  the  small 


(1)  Sandifort,  Obs.  anat.path.,  vol.  iii.  p.  11. 

(2)  Fleischmaun,  Leichenöffnungen, p.  100. 


OF  THE  DIGESTIVE  SYSTEM. 


289 


intestine,  as  when  the  development  is  normal,  this  portion  of  the  canal 
enters  last  into  the  abdomen. 

b.  The  more  or  less  perfect  continuance  of  its  primitive  connection 
with  the  umbilical  vesicle.(l) 

This  anomaly  exists  in  several  different  degrees. 

Sometimes  the  umbilical  vesicle  continues  beyond  the  usual  time, 
and  communicates  with  the  ileon  by  an  open  canal  which  the  ompha- 
lo-mesenteric  vessels(2)  attend. 

Sometimes  only  a canal  exists  ; it  varies  in  length,  and  extends 
from  the  same  point  of  the  ileon  to  the  umbilicus,  where  it  opens,  and 
the  omphalo-mesenteric  vessels  also  accompany  it. (3) 

Finally,  sometimes  a greater  or  less  prominence  exists  in  this  place, 
a prolongation  termed  the  diverticulum  of  the  ileon , this  is  often  ac- 
companied by  the  omphalo-mesenteric  vessels,  which  float  loosely  at 
its  extremity,  or  which  are  attached  to  the  umbilicus  or  to  another  re- 
gion of  the  intestinal  canal,  so  as  to  form  a plexus. 

These  three  anomalies  are  only  different  degrees  of  the  same  devia- 
tion of  formation.  This  is  proved  by  their  appearing  always  in  the 
same  place,  by  their  connections  with  the  omphalo-mesenteric  vessels, 
and  finally,  the  insensible  shades  which  each  presents  in  respect  to 
length  and  size. 

That  they  have  the  signification  we  attribute  to  them,  is  proved  : 
1st,  by  our  history  of  the  development  of  the  intestinal  canal,  by  their 
constant  co-existence  with  the  cæcum  and  vermiform  appendix,  and 
finally,  by  the  fact,  that  they  always  have  the  character  of  a primitive 
formation. 

That  they  depend  on  a primitive  formation,  is  proved  by  the  facts, 
that  they  are  always  observed  in  the  same  place,  that  they  are  formed 
by  all  the  membranes  of  the  intestinal  canal,  and  that  they  exist  simul- 
taneously with  other  primitive  deviations  of  formation,  which  arise 
from  the  development  being  arrested,  or  which,  at  least,  favor  their  pro- 
ductions. 

All  these  circumstances  united,demonstrate  that  it  is  impossible  to  re- 
gard them  purely  as  accidental  productions, (4)  and  consider  them  as 
excrescences, (5)  or  as  contractions, (6)  or  hernias(7)  of  the  ileon. 

In  fact,  the  following  arguments  have  been  opposed  to  our  theory  of 
the  diverticula  of  the  ileon. 

(1)  Meckel.  Beyträge  zur  vergleichenden  Anatomie , vol.  i.,  pt.  i.,  1308. — Id.,  Lieber 
die  Divertikel  ; in  Reil,  Archiv  für  die  Physiologie , vol.  ix.  part  iii. — Id.,  Handbuch 
der  pathologischen  Anatomie , vol.  i.  p.  553-597. — Fulling1 2 3 4 5 6 7,  Diss.  de  diverticulo  intes- 
tinali sex  mensium  embryonis  herniam  umbilicalem  referente,  Marburg,  1807. — 
Régnault,  Observation  d’ un  cas  singulier  de  volvulus  ; in  the  Journ.univ.  des  sc. 
Méd.,  vol.  ii.  p.  108. — P.  Rayer,  Cas  mortel  d'entérite  et  de  péritonite , déterminé  par 
un  diverticule  de  l’iléon  ; in  the  Archiv,  gén.  de  méd.,  vol.  v.  p.  68. 

(2)  Tiedemann,  Anatomie  der  hopflosen  Missgeburten , p.  66.  tab.  iv. 

(3)  Meckel,  in  Reil,  loc.  cit.,  vol.  ix. 

(4)  Oken,  in  Jenceer  Literaturzeitung , 1815,  no.  35. 

(5)  Fleischmann,  loc.  cit. 

(6)  Littré,  Mery,  in  M &m.  de  Paris , 1700-1701. 

(7)  Fabric  iua  and  Morgagni,  in  Morgagni,  Bp.  an.  méd,  34,  a.  17. 


290 


DESCRIPTIVE  ANATOMY. 


a.  Their  inconstancy,(l)  their  variety, (2)  while  all  the  transitory 
formations  do  not  entirely  disappear  when  the  development  is  regular 
and  also  the  vitelline  canal  in  birds  always  continues. 

b.  The  existence  of  several  diverticula  in  the  same  intestine,  or  at 
least  that  of  real  diverticula  in  parts  of  the  intestinal  canal  beside  the 
ileon.(3) 

c.  Their  frequent  coexistence  with  deviations  of  formation  by 
doubling  or  arrest  of  development. (4) 

d.  The  great  size  and  thickness  of  their  parietes,  which  even  did  a 
canal  of  the  umbilical  vesicle  exist  in  the  early  periods  of  life,  would 
indicate  an  excess  in  the  formative  power. (5) 

But  we  have  already  opposed  most  of  these  objections  before  they 
were  brought  forward,  and  it  is  easy  to  refute  them. 

The  first  proves  nothing,  for  several  other  deviations  of  formation, 
which  consist  essentially  in  the  development  being  arrested,  are  still 
more  rare  than  the  diverticula,  and  disappear  entirely  when  the  deve- 
lopment is  regular.  We  shall  mention,  for  instance,  the  permanence 
of  the  pupillary  membrane,  the  absence  of  the  extremities,  the  continu- 
ance of  the  arterial  canal,  the  urachus,  and  the  omphalo-mesenteric 
vessels,  the  fissure  of  the  uterus.  The  analogy  with  birds,  which  has 
been  adduced,  is  valueless,  since  even  in  several  birds,  as  those  of  prey, 
the  vitelline  canal  always  seems  to  disappear  entirely,  and  we  com- 
monly observe  traces  of  the  primitive  state  longer  in  the  lower  animals 
than  in  the  higher  classes. 

Against  the  second  objection,  the  extreme  rarity  of  the  anomaly  on 
which  it  is  founded,  may  be  adduced.  Farther,  we  may  ask,  if  among 
these  extremely  rare  cases,  there  are  not  some  false  diverticula  ; if  in 
others,  the  diverticulum  is  not  produced  by  distension  ; if  in  others,  it 
does  not  depend  on  the  union  of  the  intestinal  canal  with  the  um- 
bilical vesicle  at  an  unusual  place  ; finally,  if  the  deviation  of  formation 
cannot  be  developed  as  a primitive  anomaly,  differently  from  that  which 
commonly  occurs,  although  it  is  impossible  to  conclude  any  thing 
from  it  against  this  latter. 

The  third  objection  favors  our  views,  and  is  opposed  to  the  theory  it 
is  adduced  to  support  ; since  even  where  the  whole  body  is  double,  some 
organs  alone  very  rarely  present  the  same  tendency,  for  instance,  a 
supernumerary  finger  or  eye  is  not  common  in  this  case  ; while,  on  the 
contrary,  the  imperfect  formations,  especially  those  depending  on  sus- 
pended development,  as  the  fissure  of  the  vertebral  column,  the  skull, 
the  palate,  and  the  abdomen,  the  deviations  in  the  formation  of  the 
heart  and  the  intestinal  canal  by  defect,  are  then  very  common  phe- 
nomena. 

(1)  Oken,  in  Jeanœr  Literâturzeitung,  1815,  no.  26. 

(2)  Emmert,  Reflexions  sur  la  vésicule  ombilicale  ; in  the  Journ.  compl.  des  sc. 
méd.  vol.  ii.  p.  369. 

(3)  Emmert,  loc.  cit. 

(4)  Jd.,  ib. 


OP  THE  DIGESTIVE  SYSTEM. 


291 


The  fourth  objection  is  not  more  valid  than  the  other  three,  since  the 
difference  between  the  thickness  of  the  parietes  and  the  size  of  the 
cavity  of  the  diverticulum,  depend  on  the  period  when  the  development 
is  suspended,  or  on  other  accidental  circumstances,  which  exert  their 
influence  afterward.  The  oval  foramen  is  no  less  an  anomaly,  whether 
it  is  an  inch  or  a line  in  diameter,  and  accidental  mechanical  influences 
may  sometimes  enlarge  it  during  life. 

c.  The  great  size  of  the  vermiform  appendix,  depending  on  its  con- 
tinuing to  increase  after  the  type  of  the  fetus,  although  this  anomaly 
may  be  developed  at  a later  period. 

§ 2195.  The  deviations  of  formation,  which  essentially  consist  in  an 
excess  of  the  formative  power,  are  much  more  rare  than  those  we  have 
mentioned. 

We  should  probably  consider  as  such  the  division  of  the  duodenum 
into  two  canals,  the  existence  of  two  vermiform  appendices,  doubtless, 
also  the  unusual  length  of  the  intestinal  canal,  instances  of  which  are 
seen  particularly  in  the  large  intestine,  and  which  render  it  more  or 
less  tortuous,  and  especially  render  the  transverse  colon  pendant. (1) 
Perhaps  we  must  also  refer  to  this  class  the  real  diverticula  which  oc- 
cur in  other  unusual  points,  although  we  have  every  reason  to  think 
that  they  should  be  considered  as  belonging  to  those  deviations  of  for- 
mation relating  to  the  quality. 

§ 2196.  The  primitive  deviations  of  formation  which  concern  the 
quality,  relate  to  the  form  or  situation,  or  to  both.  Among  the  latter, 
we  must  arrange  the  lateral  inversions  of  the  stomach  and  intestinal 
canal,  since  in  this  case,  the  parts  are  not  only  situated  opposite  their 
usual  place,  but  also  present  a figure  the  inverse  of  that  they  normally 
possess. 

The  form  of  the  stomach  or  the  intestinal  canal,  rarely  presents  pri- 
mitive deviations  of  formation  in  respect  to  quantity  ; and  the  examples 
known  of  them  may  all  be  referred  to  anomalies  in  the  diameter. 

The  situation  of  the  stomach  is  sometimes  changed,  this  viscus  being 
turned  on  itself  so  that  its  convex  edge  looks  upward,  and  its  concave 
edge  downward.  (2) 

B.  ACCIDENTAL  DEVIATIONS  OF  FORMATION. 

§ 2197.  The  accidental  or  consecutive  deviations  of  formation  relate 
to  the  extent,  the  mass,  the  situation,  or  the  form. 

1st.  Extent. 

a.  Excess  in  extent  rarely  occurs  in  the  whole  abdominal  portion  of 
the  alimentary  canal,  but  it  is  observed  in  all  its  parts,  and  it  is  produced 
by  very  different  causes,  that  is,  particularly  by  obliteration,  contrac- 

(1)  P.  Monterossi  has  figured  a great  many  cases  of  this  kind  at  the  end  of  a memoir 
on  the  unusual  curves  of  the  large  intestine , considered  as  the  cause  of  death  in  new 
born  children , in  Brcra,  Nuovi  commentari  di  niedicina , 1819,  vol.  iv.  p.  3. 

(2)  Fleischmann,  loc.  cit .,  p.  98. 


292 


DESCRIPTIVE  ANATOMY. 


tion,  atonia,  the  latter  always  from  an  accumulation  of  substances 
within  it.(l) 

The  abnormal  distension  of  the  vessels  of  the  alimentary  canal, 
which  not  unfrequently  exists,  deserves  tobe  mentioned  here.  It  is 
most  generally  observed  in  the  rectum,  in  the  form  of  rounded  tumors, 
which  project  into  the  cavity  of  the  intestines,  and  are  termed  haemor- 
rhoids. (2)  It  is  generally  admitted  that  these  tumors  are  situated  in 
the  hæmorrhoidal  veins  ; doubtless  also,  the  arteries  contribute  to  them, 
although  we  cannot  admit  with  Cruveilhier,  that  they  are  new  forma- 
tions, an  accidental  development  of  the  erectile  tissue.  More  probably, 
they  depend  in  some  cases  on  the  dilatation  of  the  small  vessels,  and 
in  others,  on  that  of  the  larger  vessels,  and  in  the  last  case,  where  they 
appear  as  sacs,  the  dilated  portion  is  separated  from  the  rest  of  the 
vessel. 

The  vessels  of  the  stomach  are  generally  dilated  in  melena,  and  the 
black  substance  vomited,  or  which  is  found  in  the  stomach,  is  blood 
more  or  less  changed,  which  has  transuded  through  their  extremities. 

b.  Abnormal  contractions,  when  not  primitive,  are  rarely  confined 
to  a simple  deviation  of  formation.  They  generally  succeed  alterations 
of  texture,  inflammation,  and  its  consequences,  effusion,  scirrhus,  &c. 
The  first  commonly  occurs  when  the  alimentary  canal  is  not  distended 
by  the  causes  which  habitually  act  upon  it,  consequently  after  long 
fasts. 

The  whole  canal  is  affected.  A contraction  occurs  also  in  a por- 
tion of  this  canal  situated  below  a solution  of  continuity  which  entirely 
divided  it,  consequently  when  an  artificial  anus  is  formed  after  a wound 
or  strangulated  hernia. 

2d.  We  more  seldom  find  an  increase  or  diminution  in  mass  without 
an  alteration  of  texture;  the  first  occurs  particularly  in  the  muscular 
tunic,  and  supervenes  when  this  membrane  has  been  unusually  exer- 
cised. Thus  it  is  more  rare  to  find  the  stomach  dilated  than  very 
muscular  in  gluttons.  The  muscular  membrane  is  similarly  changed 
in  a herniary  portion  of  intestine. 

The  muscular  tunic  becomes  much  thinner  in  a general  loss  of 
flesh. 

3d.  Situation.  Deviations  in  situation  should  be  referred  to  the 
chapter  on  hernias,  since  they  generally  occur  in  these  affections.  The 
small  intestine  is  particularly  liable  to  a change  in  its  situation,  on 
account  of  its  greater  mobility,  its  smaller  size,  and  its  situation.  Next 
comes  the  stomach,  which  generally  emerges  through  the  linea  alba 
or  the  upper  part  of  the  abdominal  muscles,  sometimes,  however, 
through  the  umbilical  ring.  When  abnormal  openings  exist  in  the 

(1)  Chaussier,  Observation  suivie  de  reflexions  sur  une  dilatation  excessive  de 
l’estomac  ; in  the  Bulletin  de  la  soc.  méd.  d’émid.,  1823,  September,  p.  505. 

(2)  Montegre,  Des  hémorrhoides,  or  Traité  analytique  de  toutes  les  affections 
hémorrkoidalcs,  Paris,  181t). — E.  Summe,  Diss.  de  hœmorrhoidibus  œcis,  Berlin, 
1820. 

(3)  Anat.  pathol .,  vol.  ii.  p.  145. 


OF  THF  DIGESTIVE  SYSTEM. 


293 


diaphragm,  they  allow  the  stomach  to  pass  into  the  cavity  of  the 
thorax. 

4 th.  The  principal  changes  in  form  are  : 

a.  Inversion , in  which  one  portion  of  the  intestine  is  turned,  so  that 
its  inner  face  becomes  the  external,  and  the  outer  face  the  internal. 
When  this  change  occurs  at  the  lower  part  of  the  rectum,  it  is  termed 
a prolapsus  ani.  In  every  other  part  it  is  called  intussusception  or  in- 
vagination , because  the  inverted  part  enters  that  below  it.  The  first 
state  is  more  simple,  since  the  portion  of  intestine  which  forms  the  pro- 
lapsus is  composed  of  two  parts,  situated  one  on  the  other,  the  external 
of  which  is  reversed  and  the  internal  is  normal,  while  in  the  second 
case  is  added  a third,  that  into  which  the  inverted  portion  enters. 
Sometimes  we  find  a still  greater  number  of  superimposed  layers, 
there  being  two  invaginations,  one  within  the  other. 

Several  invaginations  often  occur  at  the  same  time. 

They  are  most  frequently  situated  in  the  small  intestine,  undoubt- 
edly because  it  is  the  most  movable  portion  of  the  alimentary  canal. 

Even  those  intussusceptions  which  commence  very  high  may  de- 
scend into  the  rectum  and  emerge  from  the  anus. 

The  most  common  cause  of  this  state  is  the  irregular  action  of  the 
muscular  membrane.  Sometimes,  however,  it  is  caused  mechanically 
by  tumors,  which  force  a portion  of  the  intestinal  canal  downward  and 
inward. 

Slight  invaginations  are  doubtless  not  dangerous,  and  disappear  of 
themselves  ; but  when  they  exist  to  a greater  extent  they  cause  in- 
flammation and  gangrene  of  the  herniary  portion,  which  is  usually, 
but  not  always,  attended  with  death  ; sometimes,  however,  the  gan- 
grenous portion  sloughs  off,  and  the  space  is  filled  by  adhesive  inflam- 
mation. 

5th.  Solutions  of  continuity  result  either  from  mechanical  influence, 
as  the  action  of  a cuttting  instrument,  a rupture,  or  from  a previous 
alteration  of  texture,  as  from  ulcerations.  They  are  sometimes  com- 
plete, and  then  affect  all  the  tunics,  sometimes  confined  only  to  the 
muscular  and  peritoneal  membranes,  whence  results  a hernia  of  the 
inner  membrane,  and  the  formation  of  a rounded  tumor  termed  a false 
diverticulum  {cl.  spurium).  The  false  differs  from  the  true  diverticu- 
lum by  its  rounded  form,  by  the  absence  of  several  superimposed  tunics, 
and  finally  by  its  occurring  in  every  part,  even  in  the  stomach,  but 
most  frequently  in  the  duodenum,  and  by  the  existence  of  several  at 
oncc.(l) 

II.  ALTERATIONS  OF  TEXTURE. 

§2198.  We  not' unfrequently  observe  an  alteration  in  the  texture  of 
the  intestinal  canal,  particularly  in  the  stomach,  which  is  its  softening 

(1)  We  have  enlarged  upon  this  subject  in  our  Handbuch,  der  pathologischen 
Anatomic , vol.  ii„  p.  II. 

Vol.  Ill  38 


294 


DESCRIPTIVE  ANATOMY. 


or  thinness,  and  when  occurring  in  a still  greater  extent  its  perfora- 
tion.(l)  This  alteration  is  seen  particularly  in  the  large  cul-de-sac 
and  in  the  posterior  wall  of  the  stomach,  and  commences  by  the  inner 
membrane,  which  always  appears  very  red  in  this  place.  The  edges 
of  the  perforation  are  very  irregular,  and  differ  from  those  of  a perfora- 
tion caused  by  an  ulcer  by  the  total  absence  of  thickening  and  hard- 
ness of  the  edges,  which  are,  on  the  contrary,  very  thin  and  soft. 
Sometimes  this  change  supervenes  after  death  ; sometimes  it  occurs 
during  life,  but  in  both  cases  it  is  caused  by  the  action  of  the  gastric 
juice  on  the  stomach,  and  we  may  consider  it  as  resulting  from  the 
digestion  of  the  membranes  of  the  stomach  by  this  juice,  which  effect 
results  when  the  perforation  occurs  during  life  from  some  change  in  the 
chemical  composition  of  the  gastric  fluid. (2) 

(1)  Chaussier  has  given  a good  description  of  perforations  of  the  stomach;  wc  shall 

quote  his  words.  Ulcerations  and  perforations  of  the  stomach  vary  in  form,  situation, 
and  extent.  They  are  small  and  circular,  or  large  enough  to  introduce  the  hand 
into  them.  They  may  occur  in  any  part  of  the  stomach,  but  are  seen  particularly 
at  the  base  of  this  organ,  in  the  portion  corresponding  to  the  spleen  and  diaphragm. 
Sometimes  then  the  food  enters  into  the  abdomen,  or  the  thorax  if  the  diaphragm  be 
perforated.  But  most  generally  there  is  no  ell'usion,  the  ulcerated  portion  of  the 
stomach  being  connected  with  the  adjacent  parts.  If  we  destroy  these  adhesions, 
which  are  slight,  a viscous,  and  sometimes  a fluid,  flows  from  the  stomach,  which  is 
not  fetid,  and  sometimes  has  an  odor  like  musk  ; it  is  always  brownish,  and  mixed 
with  blackish  flacculæ  or  molecules,  as  if  finely  pulverized  charcoal  was  strewed  in 
mucous  serum.  The  edges  are  soft,  broken,  and  sometimes  surrounded  with  a more 
or  less  marked  blackish  line.  In  every  other  part  the  stomach  preserves  its  usual 
form  and  consistence.  It  rio  where  presents  marks  of  engorgement  or  inflammation  : 
only  the  capillary  plexuses  of  its  follicular  membrane  seem  to  be  more  developed, 
especially  around  the  perforation.  Sometimes  these  changes  form  suddenly  in  a 
few  hours  in  healthy  persons  ; most  generally,  however,  after  several  days  of  sickness, 
and  when  no  violent  external  causc'or  poisoning  can  be  suspected  ( Bulletin  des 
sciences  médicales  du  département  de  l’Eure,  no.  53.  p.  7).  Consult  also  on  this  sub 
ject  which  relates  to  one  of  the  most  important  questions  in  legal  medicine  : Gerard, 
Des  perforations  spontanées  de  l’estomac , Paris,  an.  xii. — Morin,  Considerations 
générales  sur  l'érosion,  Paris,  1806. — G.  Laisne,  Considerations  médico-légales  sur 
les  érosions  et  perforations  spontanées  de  l'estomac;  in  the  journal  called  Médecine 
légale,  Paris,  1819,  p.  135. — J.  Cloquet,  Sur  les  perforations  intestinales;  in  the 
Nouveau  journal  de  médecine,  vol.  i.  p.  107. — Serres,  Observation  d'une  perforation 
de  V œsophage  ; in  the  Revue  médicale,  vol.  x.  p.  166. — Id.,  Observations  de  perfora- 
tions intestinales  ; same  journal,  vol.  x.  p.  170. — E.  Legallois,  Plusieurs  perforations 
du  canal  intestinal  et  spécialement  des  gros  intestins,  â la  suite  d'une  affection  tuber- 
culeuse ; in  the  Archiv,  gén.  de  méd.,  vol.  vi.  p.  68. — Louis,  Du  râmollissemcnt  avec 
amincissement  et  de  la  destruction  de  la  membrane  muqueuse  de  l'estomac  ; same 
journal,  vol.  v.  p.  5. — Abercrombie,  Observations  sur  l’inflammation  et  l'ulcération 
de  l'estomac  ; sanie  journal,  vol.  v.  p.  447. — Louis,  Observations/elatives  aux  perfo- 
rations spontanées  de  l’intestin  grêle,  dans  les  maladies  aigues  ; saine  journal,  vol.  i. 
p.  17. — U.  Coste,  Observations  sur  les  perforations  de  l'estomac;  in  the  Journ.  unie, 
des.  sc.  méd.,  vol.  xxix.  p.  257.  F.  T. 

(2)  This  is  the  opinion  of  Hunter.  We  cannot  admit  it.  It  rests  on  Hunter’s 
opinion  in  accordance  with  that  of  Spallanzani,  in  respect  to  the  gastric  juice.  But 
it  is  very  evident  that  the  gastric  juice  does  not  exist,  as  these  two  physiologists  have 
supposed,  that  it  docs  not  accumulate  in  the  stomach  between  meals,  that  it  is  se- 
creted only  at  the  moment  when  the  viscus  is  filled  witli  food,  that  this  secretion  is 
caused  by  the  impression  produced  by  the  latter,  and  so  far  from  being  identical,  it 
always  varies  according  to  the  nature  of  the  substances  from  which  the  chyme  is 
found.  Besides,  perforation  of  the  stomach  has  never  been  observed,  in  the  cases  of 
death  by  starvation  hitherto  observed,  and  that  cited  by  Ilunter  should  be  referred 


OF  THE  DIGESTIVE  SYSTEM. 


295 


When  the  stomach  is  thus  destroyed  in  one  part,  the  softening  pro- 
duced by  the  effused  fluid  extends  also  to  the  adjacent  portions. (1) 

§2199.  The  alimentary  canal  frequently  infames, (2)  especially  in 
its  mucous  membrane. 

In  regard  to  the  inflammation  of  the  stomach,  we  ought  to  remark 
that  the  inner  membrane  of  this  viscus,  which  is  the  most  subject  to 
inflammation  on  account  of  the  numerous  vessels  it  receives,  the  forma- 
tive power  it  possesses,  its  connections  with  the  skin,  and  the  direct 
effect  of  deleterious  substances  upon  it,  often  presents,  when  not  in- 
flamed, a very  deep  red  color,  which  depends  on  an  accumulation  of 
blood  in  the  small  twigs  of  the  veins,  and  is  observed  particularly  after 
death,  from  those  causes  which  favor  the  stagnation  of  blood  in  these 
vessels  by  opposing  its  return  to  the  heart. 

In  inflammation  of  the  mucous  membrane,  the  mucus  becomes 
thicker  and  firmer.  At  the  same  time  the  fibrin  is  effused  on  the  inner 
face  and  in  the  substance  of  this  membrane.  The  result  of  the  first  of 
these  phenomena  is,  the  formation  of  more  or  less  thick,  hollow,  or  solid 
cylinders,  which  pass  off  from  the  anus,  and  which  have  been  wrongly 
considered  as  the  membranes  of  the  intestine.  The  effect  of  the  se- 
cond is,  to  thicken  the  parietes,  and  thus  to  contract  the  cavity  of  the 
canal.  In  the  latter  case  partial  adhesions  sometimes,  but  rarely, 
occur,  and  probably  arise  from  ulcerations. (3) 

In  ulcers  of  the  mucous  membrane,  the  edges  are  usually  lightly 
turned  over,  uneven,  and  hard  * sometimes  also  their  edges  are  smooth, 
and,  as  it  were,  cut. 

Inflammation  and  suppuration  frequently  form  fistula  of  the  amis 
( fistula  ani ),  that  is,  a canal  which  commences  on  the  inner  face  of 
the  rectum,  descends  on  its  sides,  and  terminates  near  the  anus.  Like 
all  fistulous  passages,  this  canal  is  covered  internally  by  an  epidermis, 
similar  to  the  mucous  membranes,  and  is  surrounded  with  a dense  cel- 
lular tissue.  (4) 

In  dysentery,  where  the  inflammation  is  situated  principally  in  the 
mucous  membrane  of  the  large  intestine,  especially  of  the  rectum,  this 
membrane  frequently  mortifies  in  several  parts,  and  black  and  dry 
eschars  are  formed  on  its  surface. 


to  the  erosions  mentioned  in  the  preceding'  note.  Consult  on  this  subject  F.  G. 
Gcedecke,  De  dissolutione  ventriculi,  sive  de  digestione  quam  dicunt  ventriculi  post 
mortem,  Berlin,  1823.  F.  T. 

(1)  Yelloly,  Observations  on  the  vascular  appearance  inthe  human  stomach,  uhich 
is  frequently  mistaken for  inflammation  of  that  organ  ; in  the  Med.  chir.  trails.,  vol. 
iv.  p.  374-425. 

(2)  Scoutetten,  Recherches  d'anatomie -pathologique,  démonstrant  le  rapport  qui 
existe  entre  l'irritation  de  la  membrane  muqueuse  du  canal  intestinal  et  celle  de  la 
■méningine  ; in  the  Journ.  univ.  des  sc.  méd.,  vol.  xxviii.,  p.  257. 

(3)  Monro,  Morb.  anat... tab.  vii. 

(4)  J.  Howship,  Practical  observations  on  the  most  common  diseases  of  the  Imecr 
intestines  and  anus , London,  1820. — C.  Bell,  A treatise  on  the  diseases  of  the  urethra, 
vesica  urinaria,  prostata,  and  rectum,  London,  1820. — T.  Copeland,  Observations  on 
the  principal  diseases  of  the  rectum  and  anus,  London,  1814. 


DESCRIPTIVE  ANATOMY. 


2f)6 

All  these  phenomena  are  usually  confined  to  the  mucous  membrane. 
The  tubercular  formation,  however,  in  which  rounded,  whitish,  and 
hard  masses  are  formed,  extends  from  this  membrane  to  the  outer  face 
of  the  organ,  where  it  forms  more  or  less  evident  prominences.  This 
change  is  commonly  observed  inthe  latter  periodof  tuberculous  phthisis, 
especially  in  the  small  intestine.  The  ideerations  thus  affect  all  the 
membranes  of  the  stomach,  and  then  gradual^  extend  from  within 
outward.  They  do  not  necessarily  result  in  the  effusion  into  the  ab- 
domen of  substances  contained  in  the  organ  ; this  is  even  propor- 
tionally rare  on  account  of  the  adhesions  with  the  adjacent  parts,  or 
because  the  opening  communicates  with  another  portion  of  the  intes- 
tinal canal,  or  with  the  exterior,  when  the  wall  of  the  abdomen  ad- 
heres to  the  diseased  organ. 

Inflammation  of  the  peritoneal  coat  of  the  alimentary  canal  is  often 
followed  by  more  or  less  general  and  intimate  adhesions  between  the 
different  parts  of  the  passage.  These  adhesions  are  sometimes  so  nu- 
merous and  intimate  that  the  folds  of  the  intestines  form  one  mass, 
which  cannot  be  separated  from  the  surrounding  substance,  and  repre- 
sents only  a canal  hollowed  in  an  amorphous  mass. 

One  of  the  most  common  alterations  of  texture  in  the  intestinal  canal 
is  the  scirrhous  formation,  which  extends  from  the  vascular  tunic  and 
the  muciparous  glands,  where  it  is  primitively  situated,  to  the  mucous 
and  muscular  membranes.  It  blends  together  all  these  tunics,  and 
renders  them  thicker  and  harder  ; they  finally  present  a carcinomatous 
ulceration.(l)  This  alteration  of  structure  causes  a contraction  of  the 
canal,  which  is  often  very  great.  It  is  observed  more  particularly  in 
the  pylorus,  the  end  of  the  descending  colon,  and  the  rectum,  which 
depends  perhaps  only  on  the  disposition  of  these  parts  to  retain  for  a 
longer  period  the  substances  which  pass  through  them,  and  are  also 
more  exposed  to  irritation  and  its  consequences.  But.  the  morbid  af- 
fection extends  also  a greater  or  less  distance  to  its  primitive  source, 
so  that  it  sometimes  attacks  the  whole  stomach  and  a very  great  por- 
tion of  the  intestinal  canal. 

Very  probably  we  must  arrange  here  tlae  morbid  alterations  de- 
scribed by  Monro,  in  which  albumen  is  deposited  in  the  vascular  tunic, 
for  all  its  essential  characters  are  the  same,  and  it  differs  from  cancer 
only  in  its  form,  since  it  appears  as  small  rounded  bodies. (2) 

The  fungous  excrescences  of  the  mucous  membrane  are  much  more 
rare.  They  have  however  been  found  in  every  part  of  the  intestinal 
canal.  Thus  authors  have  described  some  cases  of  very  large  polypi 
of  the  stomach,  one  of  which  extended  from  the  cardiac  orifice  even 
within  the  duodenum. (3)  We  have  lately  found  in  the  cadaver  of  a 

(11  Bourdon,  Observations  sur  quelques  maladies  de  l'estomac;  in  the  Rev uc  mé- 
dicale, May,  1824. 

(2)  Morbid,  ahat.,  p.  17. 

(3)  Breschct,  ' Tumeur  polypcusc  développée  dans  l’ estomac  ; in  the  JRull.de  la 
far.  de  mid.,  vo).  v.,  1817,  p.  370.  Ol  lier  cases  of  tills  kind  may  be  found  in  Monro, 

' Morbid  ariat. vi. — Fabre,  (/acetic  de  santé.,  June,  1815. 


dj?  THE  DIGESTIVE  SYSTEM. 


297 


young  man  frequently  affected  with  abdominal  affections,  and  who 
died  of  violent  enteritis,  two  excrescences  of  the  mucous  membrane  of 
the  small  intestine,  one  of  which  was  about  four  lines  in  diameter,  and 
was  covered  in  all  parts  by  the  mucous  membrane,  while  the  other, 
about  an  inch  in  diameter,  had  destroyed  this  membrane,  and  was 
unattached.  These  excrescences  are  more  common  in  the  rectum(l) 
than  in  any  other  part.  They  are  similar  only  in  form,  for  they  differ 
much  in  respect  to  texture  ; since  they  are  sometimes  very  hard  and 
solid,  sometimes  spungy,  and  of  a loose  and  soft  tissue.  The  first  pro- 
bably belong  to  the  class  of  fibro-cartilages,  and  the  others  to  that  of 
fungus  hematodes. 

A tumor  of  the  internal  membrane,  described  by  Monro ' as  a milt- 
like tumor,  and  which  affects  the  stomach  particularly,  is  doubtless  a 
fungus  hematodes. (2) 

In  fact,  in  examining  the  viscera  of  individuals  who  have  died  from  a 
severe  attack  of  small-pox,  we  have  found  the  inner  membrane  of  the 
intestinal  canal  very  red,  but  have  never  seen  in  it  pustules. 

The  normal  tissues  are  rarely  formed  abnormally  in  the  intestinal 
canal.  We  must  however  mention  here,  the  fatty  tumors  developed 
on  the  inner  face  of  the  mucous  membrane, (3)  the  hairs  which  are 
found  sometimes  alone  on  the  inner  face  of  the  intestine, (4)  sometimes 
attended  with  teeth,  in  the.  stomach, (5)  the  ossifications  of  the  inner 
face  of  the  intestine, (6)  and  finally,  at  least  in  certain  cases,  hemorr- 
hoids, when  they  are  cavernous  formations. 

§ 2200.  Foreign  bodies  of  different  kinds  are  common  in  the  abdo- 
minal portion  of  the  alimentary  canal,  particularly  in  the  intestine. 

Those  seen  most  frequently  are  the  intestinal  worms,  which  in  fact 
are  more  common  here  than  in  any  other  part  of  the  body.  The  as- 
caris lumbricoides,  the  toenia  lata,  s.  bothryocephalus  latus,  and  the 
tcenia  solium,  live  principally  in  the  small  intestine,  the  trichocephalus 
dispar  in  the  large  intestine,  and  particularly  in  the  cæcum,  finally  the 
ascaris  vermieularis,  oxyuris  vermicularis,  Bremser,  in  the  large  intes- 
tine, and  particularly  in  the  rectum. 

These  worms  exist  in  the  stomach  only  accidentally,  and  generally 
even  not  till  after  death.  The  openings  through  which  they  some- 
times pass  into  the  peritoneal  cavity  are  not  formed  by  them. 

Other  foreign  bodies,  which  are  much  more  rare,  are  concretions 
introduced  accidentally  into  the  intestinal  canal.  They  are  most  com- 

(1)  Meckel,  'Handbuch  der  pathologischen  Anatomic , vol.  ii.,  pt.  ii.,  p.  511. — Lnra- 
cine,  Observation  sur  une  tumeur  fongueuse  pèdCculée  dans  le  rectum  ; in  the  Bull, 
d.e  la  soc.  méd.  d’émul. , September,  1821. 

(2)  Morbid  anatomy,  p.  160. — Itullier,  Sur  le  cancer  de  l'estomac;  in  the  Archiv, 
gen.  de  méd.,  vol.  ii.,  p.  380. 

(3)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  ii.,  pt.  ii.,  p.  124. 

(4)  Meckel,  Mémoire  sur  les  poils  cl  les  dents  qui  se  développent  accidentellement 
dans  le  corps  ; in  the  Juurn.compl.  dessc.  méd.,  vol.  iv.,  p.  122,217. 

(5)  Jîuysch,  Advefs.  anal.,  dec.  iii. 

(6)  Meckel.  Handbuch  der  pathologischen  Anatomie,  vol.  if.,  pt.  ii.,  p.  227. 


298 


DESCRIPTIVE  ANATOMY. 


monly  biliary  calculi,  which  descend  into  it  from  the  gall  bladder. 
Next  come  the  abdominal  concretions,  which  form  partially  or  wholly 
in  the  intestine.(l) 


ARTICLE  FOURTH. 

GLANDULAR  ORGANS  OF  THE  ABDOMINAL  PORTION  OF  THE 
DIGESTIVE  SYSTEM. 

§ 2201.  The  glandular  organs  of  the  abdominal  portion  of  the  di- 
gestive system, (2)  termed  also,  together  with  the  stomach,  the  chylo- 
poietic  viscera  ( viscera  chylopoietica ),  are  the  liver , the  pancreas , and 
the  spleen.  They  are  situated  in  the  upper  half  of  the  abdomen,  and 
are  intimately  connected  with  each  other,  and  with  the  stomach  and 
the  duodenum,  not  only  in  situation  but  also  in  the  vessels  and  nerves 
they  receive,  but  even,  except  in  the  spleen,  in  continuity  of  substance. 
In  fact  they  receive  their  vessels  from  the  same  trunk,  the  cceliac 
artery  ; their  nerves  come  from  the  same  source,  the  solar  plexus  ; 
finally,  the  excretory  canals  of  the  liver  and  pancreas,  which  open  into 
the  duodenum,  are  in  fact  folds  of  the  inner  membrane  of  this  intestine. 

I.  LIVER. 

A.  PERFECT  STATE. 

A.  SITUATION. 

§ 2202.  The  liver  (hepar,  jecur),( 3)  the  largest  gland  in  the  body, 
occupies  all  the  right  hypochondriac  region,  the  upper  part  of  ihe  epi- 
gastric region,  and  in  the  female  particularly,  part  of  the  left  hypo- 
chondriac region.  It  descends  on  the  right  side  lower  than  on  the  left, 


(1)  Meckel,  Remarques  sur  les  concrétions  qui  se  recontrent  dans  le  canal  intestinal 
chez  l’homme  ; in  the  Journ.  compl.  des  sc.  méd .,  vol.  ii.,  p.  125. 

(2)  J.  Fantoni,  De  jecore,  liene  et  pancrcatc  ; in  the  Disc,  renov .,  Turin,  1745. 

(3)  A.  Rolfink,  De  hepate,  Jena,  1633. — F.  Glisson,  Anatomia  hepatis , London, 
1654. — M.  Malpighi,  De  hepate  ; in  the  De  viscerum  structura,  Bologna,  1666. — J. 
B.  Bianchi,  Historia  hcpalica,  Turin,  1711. — A.  Bertrandi,  De  hepate  et  oculo,  Turin, 
1748. — A.  Franken,  Hist,  hepat.  anat.,  Leyden,  174S. — J.  G.  Gunz,  Obs.  circa  hepar , 
Leipsic,  1748.— A.  Ferrein,  Sur  la  structure  des  viscères  nommés  glanduleux , et  par- 
ticulièrement sur  celle  des  reinset  du  foie  ; in  the  Mém.dc  Paris , 1749,  p.  709. — 
M.  Ambodick,  De  hepate,  Strasburg,  1775. — F.  A.  Walter,  De  structura  hepalis  et 
vesiculœ  felloe  ; in  the  Annot.  acad.,  Berlin,  1786. — Saunders,  A treatise  on  the  struc- 
ture, economy , and  diseases  of  the  liver,  London,  1798. — J.  M.  Mappes,  Disc,  dc  peni- 
tiori  hepatis  humani  structura,  Tubingen,  1817. — Id.,  Quelques  considerations  sur 
la  structure  du  foie  et  du  rein  ; in  the  Journ.  compl.  des  sc.  méd.,  vol.  xii.,  p.  223. — 
J.  F.  Bcltz,  <lu<cdam  dc  hepatis  dignitale,  Berlin,  1822. 


OF  THE  DIGESTIVE  SYSTEM. 


299 


so  that  it  is  situated  obliquely  from  below  upward,  and  from  right  to 
left.  On  the  left  side  it  terminates  near  the  upper  extremity  of  the 
spleen  ; its  left  portion  covers  the  stomach,  the  right  generally  the 
whole  right  kidney,  but  when  the  latter  organ  is  situated  lower  than 
usual,  only  its  greater  upper  half. 

B,  DIMENSION  AND  WEIGHT. 

§ 2203.  The  transverse  diameter  of  the  liver  in  the  adult  is  usually 
from  ten  to  twelve  inches  ; the  antero-posterior  is  from  six  to  seven 
inches.  The  gland  is  two  inches  high  in  its  thickest  portion. 

The  liver  generally  weighs  about  four  pounds  in  the  adult,  so  that 
its  weight  in  proportion  to  that  of  the  whole  body  is  as  1 : 36. 


c.  FORM. 

§ 2204.  The  form  of  the  liver  is  irregular  and  quadrangular.  It  is 
much  thicker  from  one  side  to  the  other  than  from  before  backward, 
and  is  thinnest  from  above  downward. 

§ 2205.  The  liver  is  generally  divided  into  two  halves  or  lobes  (loin), 
the  right  and  the  left,  separated  on  the  upper  face  by  the  suspensory 
ligament,  on  the  anterior  edge  by  a deep  groove,  and  on  the  lower  face 
by  a deep  longitudinal  fissure,  which  extends  the  whole  breadth  of  the 
gland. 

§ 2206,  The  right  lobe  (/.  hepatis  dexter , s.  major ) is  about  four 
times  as  large  as  the  left  (l.  hepatis  sinister , s.  minor),  and  much  ex- 
ceeds it  in  all  its  dimensions,  but  particularly  in  its  thickness. 

Its  upper  face  is  uniformly  convex  ; the  lower  presents  elevations 
and  depressions  which  render  it  very  uneven. 

These  inequalities  are  connected  with  the  blood  vessels,  the  lym- 
phatics and  the  biliary  vessels  which  enter  or  emerge  from  the  liver, 
and  correspond  to  the  fissures  ( hilus ) of  the  other  glandular  organs. 

The  two  edges  of  the  liver,  the  anterior  or  inferior , and  the  posterior 
or  superior , are  generally  convex,  but  the  first  is  more  so  than  the 
other.  The  anterior  is  thin  and  sharp,  the  posterior  thick  and  blunt, 
so  that  the  upper  and  lower  faces  gradually  unite  in  that  part,  al- 
though there  is  a very  distinct  limit  between  them. 

The -left  portion  of  the  lower  face  of  the  right  lobe,  which  is  the 
smallest,  and  which  occupies  the  centre  of  the  lower  face  of  the  liver, 
considered  as  a whole,  has  the  form  of  an  H inclined  from  before  back- 
ward, the  transverse  bar  and  the  two  legs  of  which  are  formed  by  the 
fissures  (sulci,  s.  foveœ)  which  converge  behind  the  lower  face  of  the 
liver,  between  which  are  the  elevations  (lobidi). 

§ 2207.  The  transverse  or  median  fissure  (sulcus  intermedins,  s. 
transversus)  is  situated  about  the  centre,  a little  nearer  the  posterior 
than  the  anterior  edge.  We  notice  in  it  the  commencement  of  the 


300 


BESCßimVE  ANATOMY 


excretory  duel  of  the  liver,  or  the  hepatic  canal  (d.  hepatic us),  the  com- 
mencement of  the  arterial  portion  of  the  vena-porta  and  the  hepatic 
arteries.  The  hepatic  canal  is  situated  entirely  forward,  the  vena- 
portae  between  an  anterior  and  a posterior  series  of  branches  of  the 
hepatic  artery.  Each  of  these  three  vessels  divides  into  a right  and  a 
left  branch  ; from  the  hepatic  artery  are  commonly  formed  two,  which 
are  entirely  distinct,  a right  and  a left. 

§ 2208.  The  left  longitudinal  fissure  ( fossa  longiludinulis  sinistra), 
which  separates  the  right  from  the  left  lobe,  extends  from  the  anterior 
to  the  posterior  edge.  The  left  extremity  of  the  vena-portae  divides 
these  into  two  halves,  an. anterior,  longer  and  deeper,  and  a posterior, 
smaller  and  more  superficial. 

The  anterior  half  ( fovea  pro  vena  umbiiicali,  s.  lig.  terete)  is  the 
groove  for  the  umbilical  vein  or  the  round  ligament  of  the  liver. 

Gunz  has  asserted,  contrary  to  most  anatomists,  that  this  anterior 
half  is  most  generally  changed  into  a real  canal,  as  in  almost  all  ani- 
mals, by  one  or  more  bands  of  the  substance  of  the  liver,  which  extend 
like  a bridge  from  the  lower  face  of  the  great  lobe,  to  that  of  the  small, 
and  are  sometimes  also  replaced  by  a simple  prolongation  of  the  peri- 
toneal capsule  of  the  gland. 

The  posterior  half  of  the  left  longitudinal  fissure,  which  is  more  su- 
perficial than  the  anterior,  especially  toward  the  left  lobe,  is  the  fossa 
for  the  venous  canal  {fossa  pro  duc  lu  venoso),  which  is  there  directed 
from  before  backward,  from  below  upward,  and  near  its  termination  a 
little  from  left  to  right. 

It  is  continuous  posteriorly  with  the  fissure  of  the  ascending  vena- 
cava. 

We  rarely  find  it  intimately  united  with  the  venous  canal  by  a 
layer  of  the  substance  of  the  liver,  which  is  then  very  thin. 

§ 2209.  The  right  longitudinal  fissure  ( fossa  longiludinalis  dexlra) 
is  much  more  superficial,  and  its  anterior  part,  separated  from  the  pos- 
terior by  the  vena-porta,  differs  much  from  this  latter  in  form  and  in 
importance. 

The  anterior  is  planer  and  is  not  covered  by  the  peritoneum  ; it  re- 
ceives the  gall-bladder  [ fossa  pro  vosiculd  jelled).  This  depression  is 
most  generally  indicated  forward  by  a greater  or  a less  groove,  and 
sometimes  it  communicates  near  its  anterior  extremity  with  the  upper 
face  of  the  liver  by  an  opening. 

The  posterior  is  directed  from  below  upward,  and  is  continuous  with 
the  posterior  edge  ; it  is  termed  the  fossa  of  the  vcna-cava  {fossa  venae 
cavœ),  because  it  receives  the  upper  part  of  the  ascending  vena-cava. 
It  blends  posteriorly  in  the  blunt  edge  of  the  liver  with  the  fissure  of 
the  venous  canal.  It  is  rarely  wholly  or  partially  changed  into  a canal 
by  a band  of  the  substance  of  the  liver. 

About  twenty  small  hepatic  veins  proceed  from  this  fossa  from  below 
upward,  in  pairs  side  by  side,  and  empty  into  the  ascending  vena-cava  ; 
but  from  its  upper  part  arise  two  large  venous  trunks,  a right  and  a 
left,  which  terminate  in  the  same  manner. 


OF  THE  DIGESTIVE  SYSTEM. 


301 


Thus  the  vena-cava  follows,  in  the  arrangement  of  its  branches,  the 
same  law  as  the  other  vessels  of  the  liver,  and  although  the  latter  is  a 
simple  organ,  it  seems  composed  of  two  halves,  a right  and  a left. 

Its  vascular  fissures  are  separated  from  each  other  on  the  lower 
face  by  the  posterior  middle  lobe  ; they  however  blend  together  pos- 
teriorly. 

§ 2210.  The  portion  of  the  lower  face  of  the  liver,  situated  between 
the  two  longitudinal  fissures,  is  divided  by  the  portal  eminence  into  two 
halves,  an  anterior  and  a posterior. 

The  anterior,  which  is  deeper,  is  situated  between  the  depressions 
of  the  gall-bladder  and  the  umbilical  vein  on  one  side,  and  the  portal 
eminence  and  the  anterior  edge  on  the  other,  and  has  been  called  from 
its  form  the  square  lobe  (Z.  quadratus). 

The  posterior  is  smaller,  more  elongated,  narrower,  but  more  promi- 
nent, because  situated  on  a narrower  base,  is  found  between  the  porta, 
the  fissure  of  the  ascending  vena-cava,  that  of  the  venous  canal,  and 
the  posterior  edge.  It  is  termed  the  lobe  of  Spigel  ( lobulus  Spigelii, 
s.  caudatus). 

§ 2211.  The  right  portion  of  the  lower  face  of  the  great  lobe  is  the 
most  extensive  and  thickest,  and  is  uniformly  convex  or  concave. 

§ 2212.  The  left  lobe,  which  is  much  smaller  and  thinner,  gra- 
dually terminates  in  a blunt  extremity.  Its  upper  and  its  lower  faces 
are  smooth  and  united. 

Beside  the  fissures  we  have  described,  we  not  unfrequently  find, 
particularly  in  the  right  lobe,  several  which  vary  in  size  and  are  not 
constant  •,  these  are  analogous  to  the  division  of  the  liver  into  many 
lobes  in  the  mammalia. 


d.  attachments. 

§ 2213.  The  liver  is  enveloped  by  the  peritoneum,  except  the  right 
part  of  its  posterior  edge  and  the  portion  of  its  lower  face  covered  by 
the  gall-bladder.  This  membrane  is  reflected  on  it  backward  by  its 
blunt  edge,  and  forward  by  the  portal  eminence  or  the  suspensory  liga- 
ment. There  is  no  other  envelop  between  it  and  the  tissue  of  the 
gland  in  most  of  its  extent  ; we  however  find  an  intermediate  layer  of 
cellular  tissue  at  the  posterior  part  of  the  upper  face  near  the  edge. 

§ 2214.  The  liver  is  kept  in  place  by  several  folds  of  peritoneum, 
namely  : 

1st.  By  the  coronary  ligament,  at  its  posterior  edge. 

2d.  By  the  right  and  left  triangular  ligaments,  which  form  its  right 
and  left  extremities,  to  the  lower  face  of  the  diaphragm. 

3d.  By  the  suspensory  ligament,  which  is  attached  to  the  lower  face 
of  the  diaphragm  and  to  the  linea  alba. 

The  small  epiploon  unites  it  to  the  small  curve  of  the  stomach. 

A short  cellular  tissue  also  unites  it  very  loosely  to  the  right  kidney, 
which  it  receives  in  a depression  of  the  lower  face  of  its  right  lobe. 


VOL.  III. 


39 


302 


DESCRIPTIVE  ANATOM  V. 


E.  COLOR,  SPECIFIC  GRAVITY,  AND  CONSISTENCE. 

§ 2215.  The  color  of  the  liver  is  brownish  red  in  young  persons  and 
those  in  the  prime  of  life.  It  becomes  darkish  and  blacker  in  old  age. 
Its  specific  gravity  is  about  as  15  : 10. 

Its  substance  is  firm,  but  brittle.  Thus  the  liver  is  one  of  the  organs 
most  frequently  ruptured,  from  a mechanical  cause  acting  on  the  pa- 
rietes  of  the  abdomen  when  the  external  parts  are  uninjured. 

F.  TEXTURE. 

§ 2216.  The  parenchyma  of  the  liver  is  not  absolutely  homoge- 
neous. In  fact  we  do  not  find,  as  in  the  other  glands  and  the  ence- 
phalon, the  two  substances  of  which  it  is  composed  separated  from 
each,  so  that  one  is  placed  internally  and  the  other  externally.  But 
whatever  point  we  examine,  these  two  substances,  which  are  every 
where  arranged  alternately,  are  easily  distinguished.  At  first  view 
they  seem  to  form  undulated  bands  about  half  à line  thick  ; but  when 
examined  more  attentively  we  perceive  that  the  yellow  forms  a co- 
herent mass  in  all  parts  of  the  gland,  that  it  there  produces  numerous 
elevations  and  depressions,  although  interrupted  in  many  parts,  and 
consequently  represents  a very  complicated  net-work.  In  the  spaces, 
which  are  about  a line  in  diameter,  and  which  are  polygons,  we  find 
a dark  substance  which  does  not  form  a coherent  whole  like  the  pre- 
ceding, and  which  is  softer  but  less  transparent-  than  it. 

Ferrein  had  already  well  distinguished  these  two  substances. (I) 
Haller(2)  and  Gunz(3)  also  mention  its  discovery.  Autenrieth,(4) 
Bichat, (5)  Cloquet, (6)  and  Mappes,(7)  have  also  mentioned  this  struc- 
ture, which  we  have  always  thought  was  easily  seen  ; hence  we  con- 
sider as  erroneous  the  opinion(8)  that  they  are  arranged  arbitrarily. 
Physiologists,  however,  differ  in  regard  to  their  uses.  Ferrein  terms 
the  deep  colored  substance  the  medullary , and  the  bright  colored  sub- 
stance the  cortical  ; while  Autenrieth  and  Mappes  have  applied  these 
terms  in  opposite  senses.  The  views  of  these  last  two  writers  seem 
to  us  to  be  more  just  than  those  of  the  others  regarding  the  difference 
in  the  consistence  and  the  transparency  of  the  two  substances,  in  re- 
spect to  their  color,  or  finally  their  arrangement  in  regard  to  conti- 
nuity, since  in  all  these  respects  the  bright  substance  is  more  similar 

(1)  Mhn.  de  Paris , 1735,  hist.  51. 

(2)  Bibl.  anat.,  vol.  ii.,  p.  253. 

(3)  De  hepate,  p.  28. 

(4)  lieber  die  Rindensubstanz  der  Leber;  in  Reil,  Archiv,  für  die  Physiolosric, 
vol.  vii.,  1817,  p.  299-308. 

(5)  Anat.  dcscript.,  vol.  v.,  p.  93. 

(6)  Traité  d'anat.,  vol.  ii.,  p.  1032,  1033. 

(7)  Loc.  cit.,  p.  6. 

(8)  Porta),  Anal,  prat .,  1804,  vol.  v.,  p.  278. 


OF  THE  DIGESTIVE  SYSTEM. 


303 


to  the  bright  substance  of  the  encephalon,  the  spinal  marrow,  and  the 
kidneys  ; and  the  dark  substance  to  the  cortical  substance  of  these 
latter. 

When  the  yellow  medullary  substance  is  examined  attentively,  it 
seems  formed  of  small  points  or  grains. 

We  may  term  the  small  masses  composed  of  medullary  and  of  cor- 
tical substance  the  lobules  (acini),  although  they  are  more  blended 
than  in  the  other  glands,  and  are  not  separated  by  spaces  filled  only 
with  cellular  tissue  ; so  that  the  structure  of  the  liver  is  consequently 
much  less  lobular  than  that  of  the  salivary  glands. 

From  the  consistence  and  hardness  of  the  substance  of  the  liver,  the 
orifices  of  the  vessels  which  are  intimately  united  with  it  remain  ga- 
ping when  it  is  cut. 

§ 2217.  The  liver  is  formed  by  the  ramifications  of  the  biliary  ducts, 
of  the  vena-portae,  of  the  hepatic  artery  and  the  hepatic  veins,  and  by 
lymphatic  vessels  and  nerves,  united  by  mucous  tissue.  It  is,  how- 
ever, essentially  formed  by  the  biliary  vessels  and  the  mucous  tissue 
which  surrounds  them. 

§ 2218.  The  vessels  of  the  liver  are  not  all  distributed  exactly  in 
the  same  manner.  They  vary  in  their  connections  with  each  other, 
and  with  the  substance  of  the  organ. 

The  hepatic  artery,  the  vena-portæ,  and  the  biliary  ducts  are  enve- 
loped in  their  whole  course  through  the  substance  of  the  liver  by  a 
common  cellular  sheath,  a prolongation  of  the  capsule  of  Glisson. 
Hence  they  are  not  in  direct  contact  with  the  substance  of  the  gland, 
like  the  ramifications  of  the  hepatic  artery,  around  which  the  capsule 
does  not  exist,  and  they  are  more  solid  and  more  resisting  than  the 
latter. 

The  hepatic  artery  seems  to  be  intended  for  the  nourishment  prin- 
cipally of  the  tissue  of  the  liver  ; for  according  to  Glisson’s  observa- 
tions/!) which  have  since  been  proved  correct  by  Bianchi,(2)  Wal- 
ter,(3)  and  Mappes,(4)  it  is  distributed  on  the  other  vessels,  giving  rise 
there  to  a very  complex  net-work.  The  finest  ramifications,  however, 
enter  the  vena-portæ. (5) 

Its  branches  are  fewer  and  straighter  than  those  of  the  latter. (6) 
When  injected  it  is  generally  entirely  filled,  but  sometimes  this  is  true 
only  of  the  vena-portæ. (7) 

§ 2219.  The  vena-portæ  forms  by  far  the  largest  part  of  the  vascu- 
lar substance  of  the  liver.  It  ramifies  very  frequently,  and  evidently 

(1)  L.  i.,  c.  xxix.,  De  arteriœ  hepatis  distributions, 

(2)  hoc.  cit.,  pt.  i.,  cap.  viii.,  § 5. 

(3)  Loc.  cit.,  p.  96. 

(4 ) ' Loc.  cit.,  p.  13. 

(5)  Walter,  p.  96,99. 

(6)  Id.,  p.  95,  96. 


304 


descriptive  anatomy. 


like  a disk,  although  one  of  the  two  branches  is  much  larger  than  the 
other.(l) 

It  terminates  in  two  modes  ; several  branches,  some  of  which  are 
very  large  and  even  a line  in  diameter,  anastomose  with  the  corre- 
sponding twigs  of  the  hepatic  veins, (2)  and  hence  the  facility  with 
which  the  vena-portæ  is  injected  through  these  latter,  or  the  hepatic 
veins  through  the  vena-portæ. (3)  Other  and  more  minute  branches 
are  more  particularly  connected  with  the  origins  of  the  biliary  ducts  ; 
but  their  connections  are  less  intimate  than  those  we  have  mentioned, 
since  by  injecting  the  vena-portæ  we  can  never  fill  the  biliary  canals 
alone,  but  the  injection  always  passes  into  the  other  vessels,  particu- 
larly into  the  hepatic  veins. (4)  Its  most  minute  twigs  do  not  enter 
into  the  medullary  substance  of  the  liver,  but  are  distributed  in  the 
cortical  substance,  and  have  no  direct  or  proximate  connection  with 
the  first.(5) 

§ 2220.  The  biliary  canals  differ  from  the  other  vessels  of  the  liver, 
as  their  twigs  are  larger.  Only  the  large  branches  unite  in  the  man- 
ner of  a disk.  The  union  of  the  small  twigs  is  less  regular,  and  seve- 
ral proceed  from  the  same  point.  Their  parietes  are  much  firmer  than 
those,  of  the  veins.  The  muciparous  depressions  upon  their  inner 
face  on  the  outer  half  of  the  liver  do  not  exist  except  in  the  largest 
branches,  and  entirely  disappear  in  the  most  minute,  which  are  per- 
fectly smooth.  When  they  are  injected  the  injection  generally  pene- 
trates into  no  other  kind  of  vessel,  or  when  this  happens  the  lympha- 
tics,(6)  and  next  the  branches  of  the  vena-portæ  are  most  perfectly 
and  frequently  filled. 

The  roots  of  the  biliary  canals  seem  to  arise  on  the  limit  between 
the.  medullary  and  the  cortical  substance,  although  they  do  not  dis- 
tinctly pass  through  the  former.(7)  They  never  terminate  on  the  sur- 
face of  the  liver,  and  even  when  they  are  superficial,  they  penetrate 
within  the  gland. 

2221.  The  twigs  of  the  hepatic  vein  are  also  fewer  and  larger  than 
those  of  the  vena-portæ  and  the  hepatic  artery.  They  do  not  contribute 
as  much  as  the  vena-portæ,  to  form  the  substance  of  the  liver, (8) 
although  their  less  degree  of  development  is  only  apparent,  since  their 
twigs  are  so  small,  that  they  are  more  easily  destroyed  than  the  other 
hepatic  vessels.  When  injected,  the  fluid  scarcely  passes,  excepting 
into  the  vena-portæ. (9)  Their  direction  is  generally  transverse,  while 
that  of  the  other  hepatic  vessels  is  oblique  from  below  upward,  and 
almost  perpendicular,  so  that  they  cross  these  latter.  Their  final  twigs 

(1)  Mappes,  p.  13. 

(2)  Berlin,  in  the  Mém.  dc  Paris , 1765. — Walter,  p.  94,  95. 

(3)  Walter,  p.  63. — Mappes,  p.  23. 

(4)  Id.,  p.  64,  65. — Mappes,  p.  22. 

(5)  Mappes,  p.  11-13. 

(6)  Walter,  p.  70. — Mappes,  p.  24. 

(7)  Mappes,  p.  i. 

(8)  Walter,  loc.  at. 

(9)  Glisson,  p.  285. 


OF  THE  DIGESTIVE  SYSTEM. 


305 


are  more  intimately  connected  with  then:  medullary  substance  than 
those  of  the  other  hepatic  vessels,  and  it  is  more  or  less  easy  to  trace 
them  into  this  substance,  which  depends  partly  on  their  not  being  sur- 
rounded like  these  latter  by  the  cellular  capsule. 

§ 2222.  The  lymphatics  of  the  liver  are  intimately  connected  with 
the  biliary  ducts,  and  then  cavity  directly  communicates  with  them,  or 
at  least  the  substance  between  them  is  extremely  thin,  soft,  and  easily 
destroyed.  Those  of  the  different  regions  of  the  liver  do  not  anasto- 
mose together,  for  the  injection  of  one  branch  fills  only  the  portion  of  the 
organ  to  which  this  branch  is  distributed. 

B.  EXCRETORY  PORTION  OF  THE  BILIARY  SYSTEM. 

§ 2223.  The  excretory  portion  of  the  biliary  system  includes  the 
proper  excretory  duct  of  the  liver,  and  a cul-de-sac  of  this  canal  termed 
the  gall-bladder  ( cystis , s.  vesicula  fellea,  cholecystis) . 

A.  EXCRETORY  DUCT. 

§ 2224.  The  excretory  duct,  of  which  we  have  already  described  the 
portion  within  the  liver,  is  formed  by  two  membranes,  one  external, 
solid,  and  cellular,  the  other  internal,  thicker,  and  smooth  presenting 
numerous  and  very  compact  depressions.  We  distinguish  in  it  three 
portions,  the  hepatic  canal,  the  cystic  canal,  and  the  ductus  choledochus. 

The  hepatic  canal  ( d . hepaticus ),  or  the  first  portion  of  the  excretory 
duct,  arises  in  the  fissure  of  the  vena-portæ  generally  by  two  branches, 
one  on  the  right,  which  is  smaller,  and  comes  from  the  anterior  part  of 
the  great  lobe  of  the  liver,  the  other  on  the  left,  which  is  larger,  and 
arises  from  the  posterior  part  of  this  lobe,  and  from  the  left  lobe.  These 
two  branches  anastomose  at  an  acute  angle  before  leaving  the  fissure 
of  the  vena-portæ.  The  canal  formed  by  their  union  is  from  one  and  a 
half  to  two  inches  long,  and  nearly  two  lines  broad  in  the  normal  state  ; 
it  is  directed  from  above  downward,  and  from  right  to  left,  and  divides 
to  give  rise  to  the  cystic  canal  and  the  ductus  choledochus,  which 
make  a part  of  it. 

The  cystic  canal  ( cl . cysticus ) is  directed  at  an  acute  angle  forward, 
downward,  and  to  the  right.  It  is  narrower,  and  usually  a little 
longer  than  the  hepatic,  and  enlarges  to  form  the  gall-bladder. 

B.  GALL-BLADDER. 

§ 2225.  The  gall-bladder  is  situated  in  a special  depression  of  the 
lower  face  of  the  liver.  It  is  usually  pear-shaped.  The  extremity, 
near  its  orifice,  termed  the  neck  (cervix),  is  the  narrowest  part  ; it  is 
broadest  in  its  centre.  Its  anterior  extremity  terminates  in  a cul-de-sac, 
and  is  called  the  base  ( fundus ) ; it  commonly  extends  a little  beyond 
the  anterior  edge  of  the  liver.  •The  gall-bladder  generally  adheres  in- 


soc 


DESCRIPTIVE  ANATOMY. 


timately  by  its  upper  part,  to  the  lower  face  of  the  liver,  but  sometimes 
also  it  is  loosely  united  with  it  by  a fold  of  the  peritoneum.  The  peri- 
toneum covers  it  more  or  less  perfectly,  according  as  it  presents  one  or 
the  other  of  these  two  arrangements. 

We  find  below  the  peritoneum  a dense  cellular  tissue,  in  which  pro- 
ceed the  large  vascular  trunks,  and  which  is  called  the  vascular  or  ner- 
vous tunic.  The  external  face  of  the  second  tunic  presents  some  fibres 
which  are  generally  whitish,  proceed  in  different  directions,  sometimes 
very  analogous  to  those  of  the  muscular  coat  of  the  intestinal  canal,  and 
which  cannot  be  considered  as  forming  a distinct  layer. 

The  cellular  tunic  covers  the  internal  or  mucous  membrane,  the  in- 
ner face  of  which  presents  folds  which  represent  a reticular  tissue, 
formed  of  irregular  pentagons,  which  do  not  disappear  even  when  the 
gall  bladder  is  in  its  greatest  possible  state  of  distension.  Some  very 
small  openings,  which  are  observed  on  this  face,  lead  to  simple  glands 
which  are  commonly  invisible.  Only  ramifications  of  veins  are  distri- 
buted on  the  surface  of  the  folds. 

The  cystic  canal  and  the  neck  of  the  gall-bladder  are  contracted  by 
about  a dozen  transverse  folds,  which  are  real  valves,  and  arise  from 
the  internal  and  cellular  tunics.  Most  of  these  folds  have  their  loose 
edge  turned  toward  the  cavity  of  the  gall-bladder,  so  as  to  form  between 
them  and  the  wall  of  the  canal,  a depression  which  has  the  same  di- 
rection. 

These  folds  gradually  enlarge  from  the  hepatic  canal  toward  the 
neck  of  the  gall-bladder.  They  are  attached  to  each  other,  especially 
the  largest,  by  intermediate,  longitudinal,  oblique,  elevations  which  are 
less  prominent. 

§ 2226.  The  ductus  choledoclms , or  the  lower  portion  of  the  excre- 
tory canal  of  the  liver,  is  the  continuation  of  the  hepatic  and  the  cystic 
ducts.  It  is  a little  broader  than  these  two  canals,  but  it  is  more 
similar  to  the  hepatic  in  structure  and  diameter,  and  may  be  con- 
sidered the  direct  continuation  of  it,  for  it  has  the  same  direction,  and 
there  exists,  at  least  very  frequently,  along  the  opening  of  the  cystic 
canal,  a small  elevation  between  it  and  these  two  passages. 

This  canal  is  generally  about  four  inches  long  ; its  lower  extremity 
goes  to  the  posterior  wall  of  the  duodenum,  and  opens  at  its  central 
portion.  Its  diameter  is  generally  the  same  until  it  opens  into  the  in- 
testine, but  it  contracts  much  in  gliding  between  the  muscular  and  cel- 
lular tunics  of  the  latter,  and  finally  terminates  in  an  orifice  which  is 
narrower  than  the  rest  of  its  course. 

§ 2227.  When  we  cut  the  duodenum,  we  observe  in  the  posterior 
wall,  the  opening  of  the  ductus  choledochus,  in  the  form  of  an  oblong 
tubercle,  about  four  lines  in  length,  and  presenting  at  its  lower  extre- 
mity an  opening  directed  obliquely  from  above  downward  ; this  open- 
ing is  generally  situated  three  inches  below  the  commencement  of  the 
intestine,  and  is  formed  by  the  mucous  and  cellular  membranes  of  the 
latter  and  the  ductus  choledochus,  which  are  uninterruptedly  continu- 
ous with  each  other. 


OF  THE  DIGESTIVE  SYSTEM. 


307 


The  lower  part  of  this  orifice  does  not  belong  to  the  ductus  choie» 
dochus  alone,  but  it  is  common  to  the  pancreatic  canal. 

§ 2228.  The  most  evident  function  of  the  liver,  is  the  very  important 
one  to  secrete  bile,  a green,  very  bitter  alkaline  liquid,  which  is  indis- 
pensibly  necessary  to  digestion  ; its  physical  qualities  vary  much  in 
more  than  one  respect.  The  bile  is  generally  distinguished  into  cystic 
and  hepatic  ; the  first  is  thicker,  darker,  more  bitter,  and  consequently 
more  concentrated  than  the  second  ; which  differences  depend  on  the 
gall-bladder,  and  not  on  the  different  origin  of  these  two  fluids,  although 
Malpighi(l)  and  Galeati(2)  have  adopted  this  last  opinion,  or  at  least 
in  part. 

It  is  very  probable,  that  putting  out  of  view  this  difference  of  con- 
centration, the  bile  has  not  always  the  same  chemical  composition. 

It  always  contains  a considerable  quantity,  and  generally  about 
eleven-twelfths  of  water.  The  rest  is  composed,  according  to  Thenard, 
of  albumen  and  of  resin,  of  each  about  an  equal  quantity,  which  form 
almost  the  whole  of  it  ; a small  quantity  of  insoluble  yellow  substance, 
of  a still  smaller  quantity  of  soluble  substance,  finally,  some  traces  of 
soda,  of  the  phosphate,  the  sulphate,  and  the  hydrochlorate  of  soda  ; of 
the  phosphate  of  lime,  and  of  the  oxide  of  iron,  all  of  which  are  dis- 
solved in  the  water  except  the  yellow  substance,  which  is  insoluble. (3) 
The  resin  admitted  by  Thenard  and  his  successors,  is  produced,  ac- 
cording to  Berzelius,  (4)  by  the  action  of  acids  on  a peculiar  substance, 
similar  to  albumen.  This  chemist  considers  bile  composed  in  1000 
parts  : of  water  907.4  ; of  a peculiar  substance  80.0  ; of  mucus  3.00  ; 
of  soda  and  common  salts  9.6.  None  of  these  constituent  parts  con- 
tain azote  ; this  is  curious,  on  account  of  the  frequent  change  of  bile 
into  a fatty  body,  and  on  account  of  the  analogy  of  the  meconium  with 
vegetable  substances. 

Thenard  asserts  that  picromel,  a peculiar  substance  of  a sweet  and 
bitter  taste,  which  commonly  occurs  in  the  bile  of  most  mammalia, 
does  not  exist  in  that  of  man,  but  it  has  been  found  there  by  Che- 
valier.^) 

Probably  the  bile  is  formed  entirely,  or  in  great  part,  at  the  expense 
of  the  venous  blood  of  the  vena-portæ,  and  the  hepatic  artery  only 
serves  to  nourish  the  liver. 

The  principal  arguments  in  favor  of  this  opinion,  are  : 

1st.  The  distribution  of  the  hepatic  artery  in  the  vascular  mem- 
branes. 

2d.  The  existence  even  of  the  system  of  the  vena-portæ. 

3d.  The  great  analogy  between  the  venous  blood  and  the  bile,  and 
between  it  and  the  arterial  blood. 

. (1)  De  liene,  c.  vi. 

(2)  Com.  Bonon.,  vol.  i.  ib.  vol.  ii.  p.  i. 

(3)  Mem.  de  la  soc.  (PArcueil,  vol.  i. 

(4)  Med.  ckir.  trails.,  vol.  iii. 

(5)  Annales  de  chimie  et  de  physique,  vol.  ix. 


30S 


DESCRIPTIVE  ANATOMY. 


4th.  The  relation  between  the  caliber  of  the  hepatic  vein  and  the 
size  of  the  liver,  without  regard  to  the  abundance  of  the  biliary  secre- 
tion, while  this  latter  circumstance  is  always  attended  with  a greater 
development  of  the  vena-portæ. 

The  arguments  adduced  against  this  theory,  are  : 

1st.  The  absence  of  the  system  of  the  vena-portæ  in  the  invertebral 
animals. 

2d.  The  cases  where  the  vena-portæ  opens  into  the  vena-cava,  and 
the  hepatic  artery  is  unusually  large. 

3d.  The  correspondence  between  the  caliber  of  the  excretory  duct 
of  the  liver  and  that  of  the  hepatic  artery,  and  the  disproportion  be- 
tween that  of  the  hepatic  canal  and  that  of  the  vena-portæ. 

These  arguments  do  not  refute  those  on  the  other  side.  We  have 
reasons  for  thinking  that  the  arterial  blood  of  the  invertebral  animals 
is  perhaps  more  proper  for  the  secretion  of  bile  than  that  of  the  verte  - 
brated  animals.  Possibly,  also,  the  arterial  blood  of  the  latter  was 
more  appropriate  for  this  use  in  the  anomaly  on  which  the  second  ar- 
gument rests,  than  generally,  because  the  biliary  secretion  then  did 
not  contribute  to  render  the  blood  of  the  vena-portæ  more  analogous  to 
that  which  circulates  in  the  arteries.  Farther,  all  the  known  cases  of 
this  anomaly  have  been  observed  in  children,  the  bile  being  less  bitter 
and  less  in  quantity  than  usual.  As  to  the  third  objection,  the  hepatic 
artery  compared  with  the  arteries  of  the  other  secretory  organs,  seems 
too  small  to  admit  that  it  serves  for  secretion  and  nutrition. 

Some  physiologists,  regarding  the  size  of  the  liver,  its  constant  ex- 
istence, and  the  frequency  of  its  diseases,  have  been  led  to  believe  that 
it  fulfills  in  the  economy  another  function  from  that  of  secreting  bile  ; 
but  this  other  function  is  not  proved.  Theuses  of  the  bile  .are not  confined 
to  digestion,  but  it  is  connected  with  the  whole  vital  action  ; in  this  re- 
spect, the  secretion  which  forms  it,  prevents  an  excess  of  hydrogen  and 
carbon  in  the  body,  as  is  indicated  by  its  increase  when  the  respiratory 
function  diminishes  in  the  animal  series,  when  it  does  not  exist  as  in 
the  fetus,  or  when  it  is  deranged  as  in  certain  diseases. (1) 

The  purpose  of  the  circulation  of  the  vena-portæ,  however,  may  also 
be  to  attenuate,  to  assimilate  foreign  substances  brought  by  the  venous 
system  into  the  intestinal  canal,  and  thus  diminish  the  injurious  in- 
fluence they  might  exercise  on  the  body. 

C.  DIFFERENCES  DEPENDING  ON  DEVELOPMENT. 

2229.  The  differences  depending  on  the  development  of  the  liver(2) 
relate  to  its  volume,  situation,  form,  and  texture. 

1st.  The  liver  is  very  large  during  the  first  week  of  gestation,  and 
we  may  say  from  the  first  moment  of  its  appearance,  that  it  is  propor- 

(1)  Meckel,  Abhandlungen , 1806. 

(2)  Walter,  loc.  cit.,  sect.  i. — A.  Portal,  Observations  sur  la  situation  des  viscères  du 
bas-ventre  chez  les  enfans,  et  sur  le  déplacement  qu’ils  éprouvent  dans  un  âge  plus 


OF  THE  DIGESTIVE  SYSTEM. 


309 


tionally  much  larger  the  younger  the  fetus  is.  Thus,  in  the  fetus  of 
three  weeks,  its  weight  is  one  half  that  of  the  rest  of  the  body,(l)  and 
even  in  the  full  grown  fetus  it  is  to  the  latter  as  1 : 18,  or  as  1 : 20, 
while  the  relation  is  as  1 : 35-36  in  the  adult.  But  the  great  propor- 
tional size  of  the  liver  diminishes  at  the  end  of  the  first  half  of  gestation, 
because,  after  this  period,  the  gland  increases  more  slowly.  It,  how- 
ever, continues  to  grow  till  birth  ; but  afterward  the  absolute  weight 
and  size  diminish  until  the  end  of  the  first  year,  for  we  have  found  in 
five  new  born  children,  that  the  liver  was  one  quarter  heavier  than  in 
five  other  children  from  eight  to  ten  months  old. 

2d.  The  liver  at  first  occupies  a much  greater  space  the  younger 
the  fetus  is  ; even  at  the  third  or  fourth  month  of  gestation,  it  nearly 
fills  the  cavity  of  the  abdomen,  descends  to  the  crest  of  the  ileum,  and 
covers  the  other  viscera.  This  difference,  however,  partly  depends 
upon  its  being  situated  more  perpendicularly  at  first,  so  that  then,  that 
face  which  is  afterwards  superior,  looks  forward,  and  that  which  is  to 
be  inferior,  backward. 

3d.  Its  formation  is  at  first  as  much  more  symmetrical  as  is  its  situ- 
ation, and  it's  left  lobe  differs  less  in  size  from  the  right  lobe,  and  the 
limit  between  these  two  parts  corresponds  more  to  the  median  line. 
The  absolute  diminution  mentioned  above,  takes  place  almost  entirely 
at  the  expense  of  the  left  lobe,  for  while  during  this  period,  the  right 
lobe  preserves  the  size  it  had  at  birth,  and  often  even  increases  a little; 
the  left  diminishes  in  every  direction,  so  that  in  a child  of  a year  old,  it 
is  hardly  half  as  large  as  in  a new  born  child  ■ the  lobe  of  Spigel,  on 
the  contrary,  is  more  developed.  The  liver  is  at  first  more  rounded, 
and  its  lower  face  is  more  convex  than  it  is  afterwards. 

4th.  Its  tissue  is  softer,  more  homogeneous,  more  brittle,  and  more 
vascular  in  the  earlier  periods  of  life  than  subsequently,  where  the  ves- 
sels diminish  in  size,  and  many  of  them  disappear.  We,  however, 
very  readily  distinguish  the  two  substances  in  the  full  grown  fetus. 

5th.  Its  coloris  at  first  a bright  grayish  brown  ; it  does  not  become  a 
deep  red  until  after  the  first  half  of  gestation  ; its  tint  brightens  shortly 
after  birth,  and  its  tissue  then  changes  also  a little  in  appearance. 

§ 2230.  The  gall-bladder  isatfirst  entirely  concealed  in  the  substance 
of  the  liver,  is  proportionally  very  long,  narrow,  filiform,  a little  en- 
larged at  its  lower  extremity,  and  empty.  Its  cavity  cannot  be 
seen  except  by  the  aid  of  the  microscope.  Its  inner  membrane  is 
smooth  until  the  sixth  month  of  gestation  ; broad,  irregular  elevations 
are  then  developed  in  it,  between  which  are  narrow  depressions,  similar 
to  superficial  grooves.  These  grooves  gradually  become  deeper,  and 
also  more  numerous,  and  many  fissures  are  developed  on  the  surface 


avance;  in  the  Mémoires  de  Paris,  1771. — Id.,  Observations  sur  la  situation  du  foie 
dans  l’etat  naturel,  arec  des  remarques  sur  la  manière  de  connaitre,  par  le  tact , plu- 
sieurs de  ses  maladies  ; in  the  Mém.  de  Paris,  1773. — J.  S.  Schumann,  Dehepatis 
inembryone  magnitudinis  causis  ejusdcmquefundionc  cum  infœlutum  inhomine 
nato,  Breslau,  1817. 

(1)  Walter,  loc.  cit.,  p.  45 
Vol.  iff.  40 


310 


DESCRIPTIVE  ANATOMY. 


of  the  elevations  ; hence,  regular  and  narrow  cellules  are  formed,  which 
are  separated  by  .thin  intermediate  septa. 

Notwithstanding  its  primitive  narrowness,  the  gall-bladder  is  never 
deficient  at  any  period,  according  to  our  observations,  as  one  would  be 
led  to  believe  from  some  cases  where  its  total  absence  has  been  assert- 
ed. Its  situation  also  in  regard  to  the  other  biliary  organs,  is  always 
the  same-  ~ consequently  it  never  arises  by  a kind  of  granulation,  deve- 
loped from  the  extremity  of  the  biliary  passage,  but  it  arises  in  the 
groove  at  the  lower  part  of  the  liver,  which  is  destined  particularly  for  it, 
and  which  is  at  first  proportionally  much  deeper  than  in  the  adult. 
We  have  never  known  it  to  communicate  with  the  liver  at  first  by 
one  or  more  6peciul  canals,  while  we  have  seen  it  manifestly  terminate 
in  a cul-de-sac. 

D.  ABNORMAL  STATE. 

§ 2231.  The  liver  is  one  of  the  organs  most(l)  frequently  abnormal 
in  more  than  one  respect,  but  principally  in  its  texture,  which  undoubt- 
edly depends  on  the  numerous  organic  elements  which  compose  it 


A.  LIVER. 

§ 2232.  The  deficiency  of  the  liver  has  hitherto  been  observed  only- 
in  some  acephalous  monsters  ; in  these  it  is  the  rule,  which  has  but  few 
exceptions,  that  the  liver  is  always  very  small. 

This  organ  sometimes  preserves  the  same  situation  as  in  the  fetus, 
which  depends  on  the  imperfect  development  of  the  anterior  face  of  the 
abdomen.  In  this  case  it  is  sometimes  situated  externally,  forming 
either  alone  or  with  the  other  viscera,  an  umbilical  hernia,  in  which  it  is 
wholly  or  but  partially  contained.  It  exists  more  rarely  in  the  cavity 
of  the  thorax,  on  account  of  the  imperfect  development  of  the  dia- 
phragm. Sometimes,  in  these  two  cases,  especially  the  first,  the  her- 
niary part,  forms  a prolongation,  which  is  attached  to  the  peduncle , 
this  may  give  rise  to  the  opinion  that  two  livers  exist.  Sometimes, 
also,  when  no  similar  mechanical  cause  exists,  the  liver  is  divided  by 
more  or  less  deep  grooves,  into  a greater  or  less  number  of  distinct 
lobes. 

Sometimes  an  anomaly  of  the  liver  exists,  similar  to  the  latter  in  ex- 
ternal appearance,  but  differing  much  from  it  in  form  and  origin.  It 
consists  in  fractures  of  this  organ,  which  are  frequent  on  account  of  its 
fragility,  even  when  the  external  parts  are  uninjured  from  externa! 

(1)  Portal,  Observations  sur  la  nature  et  le  traitement  des  maladies  de  Joie,  Paris, 
181 3. — Farre,  The  morbid  anatomy  of  the  liver , London,  1812*1815. — J.  Thomas,  A 
treatise  on  the  diseases  oj  the  liver  and  digestive  organs , London,  1820.— J.  Johnston, 
A treatise  on  derangement  of  the  liver,  London,  1820. — J.  Faithorn,  Facts  and,  obser- 
vations on  liver  complaints  and  bilious  disorders  in  general,  Philadelphia,  1820. 


OF  THE  DIGESTIVE  SYSTEM. 


311 


causes,  acting  not  only  on  the  region  of  the  body  in  which  it  is  situa- 
ted, but  also  upon  remote  parts. 

It  is  rare  that  the  liver  is  abnormally  small  from  a primitive  devia- 
tion of  formation,  but  it  often  diminishes  in  the  course  of  time,  particu- 
larly in  advanced  life,  and  finally  becomes  unusually  hard  and  firm  ; 
this  state  is  termed  scirrhus , although  this  term  is  not  perfectly  con- 
venient.- 

Hypertrophy  (1)  of  the  liver  is  one  of  its  most  common  affections  ; it 
supervenes  at  all  periods  of  life,  but  most  frequently  in  advanced  age  : 
it  is  generally  attended  with  a greater  or  less  alteration  of  texture,  and 
particularly  with  induration , even  when  it  does  not  depend  solely  on 
new  formations  within  the  gland. 

Induration  of  the  liver,  however,  is  not  always  attended  by  its  hy- 
pertrophy, although  the  contrary  is  generally  admitted,  since  the  latter 
is  sometimes  attended  with  softening.  Hypertrophy  of  the  liver  fre- 
quently attends  chronic  general  diseases,  especially  rachitis,  scrofula, 
and  dropsy.  In  this  case  the  gland  is  usually  harder  than  in  health  : 
but  in  scrofula,  on  the  contrary,  where  we  find  hypertrophy  at  least  as 
frequently,  its  tissue  is  softer  than  in  the  normal  state.  The  enlarge- 
ment,of  the  liver,  which  usually  attends  pulmonary  affections,  is  evi- 
dently, at  least  in  most  cases,  an  effort  of  nature  to  restore  health. 

Induration  of  the  liver  is  the  most  frequent  alteration  of  texture,  and 
it  often  exists  with  or  without  enlargement.  Softening  of  the  liver  is 
much  more  rare,  and  exists  sometimes  with,  and  sometimes  without 
atrophy  of  the  gland. (2) 

The  new  formations  in  the  liver  are  rarely  repetitions  of  the  normal 
tissues  : the  most  common  anomaly  is  the  change  into  fat,  which  exists 
in  several  different  degrees,  usually  affects  the  whole  organ,  and  is  ob- 
served in  the  idle  and  luxurious. 

Accidental  ossification  is  generally  developed  on  the  edge  of  the 
liver,  below  the  peritoneal  coat.  Probably  it  is  only  a change  of 
another  accidental  formation,  for  instance,  of  one  of  those  serous  or 
fibroserous  cysts,  often  developed  in  the  liver,  where  they  form  hy- 
datids. 

The  liver  is  not  unfrequently  the  seat  of  entirely  new  formations, 
generally  termed  tubercles  (tuber a)  .(3)  These  tumors  are  rarely  in- 
closed in  a cyst,  and  are  rounded.  They  are  generally  whitish,  sel- 
dom red  or  brown.  They  vary  in  size  from  three  to  four  inches.  They 
are  frequently  very  numerous,  being  developed  in  the  centre  of  the 
liver,  which  is  otherwise  healthy.  Like  most  new  formations,  they  are 

(1)  V.  Murat,  Sur  l’hypertrophie  du  foie  ; in  the  Bull,  de  la  soc.  mod.  d'emuL, 
September,  1821. 

(2)  Portal,  p.  117. 

(3)  V.  Murad  Des  moyens  de  distinguer  entre  elles  les  diverses  affections  du  foie, 
désignées  sous  les  noms  de  tubercules  scrofuleux,  d'hydatides,  de  squirrhe,  d'hydro- 
pisie  enkystée,  généralement  confondues  sous  le  nom  d' obstructions  ; in  the  Bull,  de 
la  soc,  méd.  d' émut-,  September,  1821. 


312 


DESCRIPTIVE  ANATOMY, 


generally  albuminous.(l)  Those,  however,  which  have  a brownish 
tint,  appear  from  some  recent  experiments,  to  be  more  analogous  with 
gelatine. (2)  The  diseases  they  resemble  are  principally  scrofula  or 
fungous  hæmatodes. 

AH  the  anomalies  in  the  mass,  size,  and  consistence  of  the  liver 
hitherto  mentioned,  all  the  accidental  formations  mentioned  in  this 
gland,  supervene  principally  after  the  immoderate  use  of  arderlt  spirits. 
As  they  render  the  liver  unfit  for  the  secretion  of  bile,  or  prevent  the 
excretion  of  that  which  it  forms,  they  frequently  occasion  jaundice. 
This  affection  depends  on  a deposition  of  bile  in  a greater  or  less  num- 
ber of  organs  and  fluids,  particularly  in  the  skin.  It  may  also  be  de- 
termined by  the  adjacent  organs,  and  sometimes  we  discover  no  altera- 
tion to  which  it  can  be  attributed. 

From  the  important  functions  of  the  liver,  and  also  the  intimate  con- 
nection between  it  and  the  mind,  this  organ  varies  more  or  less  in  all 
general  chronic  and  in  all  mental  affections. 

Entozoaries  are  developed  in  this  gland  more  rarely.  ' The  animals 
most  commonly  found  there  are  hydatids,  which  occur  in  the  liver  more 
frequently  than  in  any  other  organ  ; they  are  extraordinarily  large 
and  numerous,  and  form  very  rapidly  ; they  are  generally  developed 
in  one  point,  rarely  in  several,  and  most  commonly  in  the  right  lobe. 
They  are  commonly  separated  from  the  healthy  substance  of  the  organ 
by  cysts,  usually  formed  by  several  layers.  They  not  unfrequently 
destroy  the  liver  to  a great  extent,  and  quitting  the  place  where  they 
are  formed,  generally  proceed  outward,  most  commonly  by  entering 
into  the  intestinal  canal,  more  rarely  into  the  chest  and  lungs,  some- 
times even  directly  through  an  opening  in  the  common  integuments. 

Biliary  concretions  are  more  rare  in  the  liver  ; probably  they  al- 
ways form  in  the  biliary  passages,  whence  they  afterwards  pass  into 
the  substance  of  the  gland. 

B.  BILIARY  PASSAGES. 

§ 2233.  Sometimes,  but  rarely,  a part  of  the  biliary  passages,  par- 
ticularly the  gall-bladder,  is  deficient(3)  from  a primitive  deviation  of 
formation,  although  this  anomaly  does  not  necessarily  exercise  an  in- 
jurious influence  on  the  health,  which  is  less  astonishing,  since,  accor 
ding  to  the  experiments  of  Herlin,  the  gall-bladder  may  be  extirpated 
in  cats  without  inconvenience,  and  it  is  normally  absent  in  many 
animals.  On  the  contrary,  the  entire  absence  of  the  biliary  passages(4) 
is  always  attended  with  the  most  fatal  results. 

(1)  Portal,  p.  95,  Des  obstructions  albumineuses  du  foie. 

(2)  Portal,  p.  98,  Des  obstructions  gélatineuses  dufoie. 

(3)  Ollivier,  Note  sur  V atrophie  de  la  vésicule  biliare  ; in  the  Archiv,  gév . de  méd., 
yol.  v.,  p.  196. 

(4)  Home,  Phil,  frans.,  1813,  pt.  ii-,  p.  146-158, 


OF  THE  DIGESTIVE  SYSTEM. 


313 


We  rarely  also  meet  in  the  biliary  passages  deviations  of  formation 
in  regard  to  the  quality,  such  as  the  existence  of  hepato  cystic  ducts 
(d.  hepato-cystici ),  going  directly  from  the  lower  face  of  the  liver  into 
the  gall-bladder,  the  slow  union  of  the  two  roots  of  the  hepatic  canal, 
the  opening  of  one  or  more  branches  into  the  cystic  canal,  or  even  into 
the  gall-bladder,  the  insertion  of  the  ductus  choledochus  in  a point 
different  from  the  intestinal  canal,  or  even  in  the  stomach. 

Of  all  the  biliary  passages,  the  gall-bladder  most  frequently  presents 
anomalies  of  this  kind,  since  when  it  is  divided  by  a contraction  into 
two  cavities,  placed  successively  in  a longitudinal  direction,  or,  as  is 
more  rare,  when  a longitudinal  septum  divides  it  into  two  parts  adapted 
one  to  the  other.  The  enlargement  and  the  contraction  of  the  biliary 
passages  generally  depends  on  mechanical  causes,  among  which  we 
must  place  first  the  biliary  calculi  contained  within  them,  next,  as  is 
more  rare,  the  engorgement  of  the  lymphatic  glands,  which  compress 
it  from  without  inward.(l)  The  gall-bladder  may  be  contracted 
or  dilated  by  the  calculi  within  it.  The  contraction  and  the  total  obli- 
teration of  its  cavity  occur  when  a few  or  small  calculi  prevent  by  their 
situation  the  bile  from  entering  it.  On  the  contrary,  numerous  or  large 
calculi,  either  alone  or  together  with  the  bile,  often  dilate  the  gall- 
bladder considerably  when  they  are  so  situated  as  not  to  prevent  en- 
tirely the  entrance  or  departure  of  the  bile,  or  when  they  exist  in  the 
ductus  choledochus.  Sometimes  the  gall-bladder  is  enormously  dis- 
tended, simply  by  an  increased  secretion  of  bile,  without  any  mechanical 
obstruction  ; the  membranes  of  this  latter  are  then  generally  thin, 
while  in  the  opposite  state  they  are  very  thick.  Sometimes  the  calculi 
are  separated  by  perfect  septa. 

New  formations  rarely  occur  in  the  gall-bladder  ; we  must  mention 
as  such,  however,  the  osseous  plates  sometimes  developed  on  the 
outer  face  of  the  mucous  membrane,  and  the  hairs  inserted  on  its  inner 
face. 


(1)  Andral  ( Observations  sur  l’oblitération  des  canaux  biliaires;  in  the  Archiv, 
gen.  de  méd.,  vol.  vi.,  p.  16)  admits  four  principal  causes  of  perfect  or  imperfect, 
transient  or  permanent  obliteration  of  the  biliary  passages  ; these  are  the  obstruc- 
tion of  their  cavity  by  a foreign  body,  a compression  upon  their  parietes  by  mem- 
branous folds  and  by  tumors  of  different  kinds,  a spasmodic  contraction  independent 
of  all  inflammation,  and  an  inflammation  followed  by  the  engorgement  of  the  mu- 
cous membrane  and  its  thickening.  He  remarks  that  the  first  two  causes  are  fre- 
quent, that  in  most  cases  the  third  has  rather  been  supposed  than  demonstrated,  and 
that  physicians  have  not  yet  attended  to  the  fourth.  The  latter,  however,  seems  to 
be,  if  not  always,  at  least  very  frequently,  a consequent  of  a gastro-intestinal  inflam- 
mation; it  is  not  unusual,  and  we  have  every  reason  to  think  that  it  always  exists 
in  thé  cases  where  the  nervous  pathology  led  one  to  suppose  the  third.  Like  all  in- 
flammations, that  of  the  biliary  passages,  whether  acute  or  chronic,  is  attended  with 
the  thickening  of  the  parietes  of  the  canal,  which  is  finally  changed  into  a ligamen- 
tous cord.  F.  x. 


314 


DESCRIPTIVE  ANATOMY 


C,  BILE. 

§ 2234.  The  bile  is  often  abnormal  in  its  physical  and  chemical 
qualities,  although  we  cannot  always  discover  a certain  connection 
between  its  anomalies  and  the  state  of  the  liver.  It  however  seems 
less  bitter  when  this  organ  is  changed  into  fat. 

The  most  striking  anomaly  is  that  resulting  from  the  presence  of 
biliary  calculi.(l) 

These  concretions,  which  are  found  in  aged  persons,  or  in  those  who 
lead  a sedentary  life,  differ  from  each  other  in  situation,  composition, 
•color,  number,  size,  texture,  form,  and  consistence. 

1st.  Situation.  The  biliary  calculi  generally  occur  in  the  gall-blad- 
der, so  that  they  seem  to  be  developed  in  this  organ.  They  have 
been  found  also  in  the  biliary  passages,  in  the  substance  of  the  liver, 
although  proportionally  very  rarely.  Sometimes  also  they  are  situated 
in  the  hepatic  or  cystic  canal,  or  in  the  ductus  choledoch  us,  but  they 
finally  fall  into  the  gall-bladder.  Not  unfrequently  they  leave  the 
ductus  choledochus  and  pass  into  the  intestinal  canal. 

The  rarest  case  is  where  they  occur  out  of  the  cavity  of  the  bili- 
ary passages  in  the  substance  of  the  liver,  or  in  the  membranes  of  the 
gall-bladder.  The  former  may  be  formed  in  the  place  where  they 
occur  ; but  the  second  are  doubtless  primitively  developed  in  the  cavity 
of  the  gall-bladder,  and  afterwards  glide  between  its  membranes,  and 
are  then  inclosed  by  the  closing  of  the  opening  which  at  first  existed, 
although  it  is  admitted  they  are  formed  in  the  place  even  where  they 
are  observed  ; and  this  fact  has  even  been  cited  to  prove  that  the  bile 
is  partially  secreted  by  the  glands  of  the  gall-bladder.  (2) 

The  justice  of  our  etiology  is  demonstrated  by  the  fact,  that  calculi 
are  sometimes  found  in  the  depressions  of  the  gall-bladder,  which  case 
is  evidently  intermediate  between  that  where  they  are  entirely  loose  in 
the  cavity,  and  where  they  are  situated  on  the  outside  of  it  and  en- 
circled in  the  membranes. 

2d.  Chemical  composition.  The  chemicafcomposition  of  the  biliary 
calculi  generally  causes  all  those  properties  of  which  we  have  yet  to 
speak.  They  are  composed  principally  of  two  different  substances  ; 
one  more  or  less  dark  in  color  and  brownish,  and  the  other  white  ; 
the  latter  is  termed  cholesterine.  The  bile  contains  none  of  it  in  the 
normal  state. (3)  The  other  is  the  yellow  coloring  substance  of  this 

(1)  Vicq-d’Azyr,  in  the  Mém.  de  la  soc.  de  mid.,  1779.- — Fourcroy,  Sur  les  calculs 
des  animaux  ; in  t lie  Annales  du  Muséum,  vol.  i. — S.  T.  Sœmmerring-,  De  concre- 
mentis  biliariis,  Frankfort,  1793.— Mosovius,  Diss.  de  calculorum  animalium  origine 
et  naturâ,  Berlin,  1812. 

(2)  D.  G.  Galeati,  De  calculxs  in  cysti  fcllcâ  et  mira  ejus  tunicas  repertis  ; in  the 
Comm.  Bonon.,  vol.  i.,  p.  354. — Ici.,  De  cystis  fclleœ  duclibus,  same  journal,  vol.  i., 
pt.  ii.,  p.  331. 

(3)  Chevrcul  has  detected  it  in  the  bile  of  man  and  several  animals  ( Note  sur  la 

présence  de  la  cholestérine  dans  la  bile  de  l’homme  ; in  the  Jourrt.  de  physiol,  cxvér., 
vol.  iv.,  p.  267).  F.  T. 


or  THE  DIGESTIVE  SYSTEM. 


315 


fluid.  The  cholesterine  probably  arises  from  the  change  of  a peculiar 
substance  which  exists  in  the  bile. 

The  biliary  calculi  also  contain  a little  of  bile,  which  is  easily  sepa- 
rated from  it  by  water. 

We  rarely  find  carbonate  of  lime  on  then  surface.(l) 

3d.  Color.  These  concretions  are  more  or  less  colored  from  the 
brighest  yellow  to  the  deepest  dark  brown,  because  they  generally 
contain  the  substances  mentioned  above.  Those  only  which  are 
formed  of  cholesterine  are  entirely  white,  and  they  are  very  un- 
common. Farther,  the  tint  varies  in  the  different  parts  of  a biliary 
calculus. 

4th.  Number.  It  varies  from  one  to  several  hundreds.  The  calculi 
formed  of  pure  cholesterine  are  usually  single,  or  at  least  very  few. 

5th.  Volume.  It  varies  no  less  than  the  number,  and  usually  hi  an 
inverse  ratio.  The  calculi  of  pure  cholesterine  are  generally  larger  than 
the  compound  concretions.  Not  unfrequently  one  of  them  fills  the 
gall-bladder,  and  even  distends  it. 

6th.  Form.  The  biliary  calculi  are  generally  more  or  less  round  ; 
those  of  pure  cholesterine  are  more  oblong.  Their  form  is  modified 
also  by  their  number,  since  the  friction  between  them  renders  their 
surface  smooth.  Hence  why  those  of  cholesterine  are  generally 
more  corrugated  than  the  others  ; but  these  concretions  rarely  pre- 
sent sharp  points. 

7th.  Their  texture  varies. 

a.  The  biliary  calculi  are  generally  full  and  solid  ; we,  however, 
have  one  which  is  hollow. 

b.  They  are  formed  of  several  superimposed  and  differently  co- 
lored layers. 

c.  These  layers  are  sometimes,  though  rarely,  composed  of  one  of 
the  two  substances  mentioned  above.  In  the  contrary  case  they  are 
all  colored,  and  differ  only  in  their  shade  of  color.  We  not  unfre- 
quently find  externally  an  entirely  white  layer. 

d.  The  fight  colored  layers  have  generally  more  oi  less  evidently 
a radiated  and  fibrous  texture.  It  is  often  easy  to  see  that  they  are 
formed  of  very  oblong  pyramids  slightly  connected  with  each  other, 
the  summits  of  which  converge  towards  the  centre.  This  form  seems 
to  depend  on  the  cholesterine,  for  it  is  never  more  apparent  than  in  the 
calculi  formed  by  this  fatty  body,  and  it  decreases  inversely  with  the 
color. 

e.  Consistence.  Biliary  calculi  generally  are  neither  very  hard  nor 
solid.  They  are  much  softer  and  more  brittle  than  the  urinary  con- 
cretions. Sometimes,  however,  they  are  considerably  hard.  Those 
of  pure  cholesterine  are  generally  harder  than  the  others,  being  even 
very  firm  and  solid  ; but  they  are  frequently  also  very  soft,  while 
others  which  are  more  deeply  colored  are  considerably  hard. 


(1)  London  mod.  repository. , vol.  iv.,  p.  469, 


316 


DESCRIPTIVE  ANATOMY. 


II.  PANCREAS. 

§ 2235.  The  pancreas(  1 ) is  the  largest  of  the  salivary  glands.  Its 
weight  and  size  are  three  or  four  times  those  of  the  parotid  gland,  as 
it  is  six  inches  long  and  one  thick,  and  weighs  from  four  to  six  ounces. 
It  is  oblong,  and  is  situated  transversely  at  the  upper  part  of  the  abdo- 
minal cavity,  before  its  posterior  wall,  in  front  of  the  first  and  second 
dorsal  vertebra,  behind  the  stomach.  Its  left  extremity  generally 
touches  the  spleen  and  the  left  kidney.  It  passes  before  the  aorta,  and 
its  right  extremity  is  situated  between  the  upper  and  lower  folds  of  the 
duodenum. 

It  is  included  between  the  two  layers  of  the  transverse  mesocolon, 
which  slightly  adheres  to  its  upper  part,  and  does  not  cover  it  poste- 
riorly: 

Its  figure  is  that  of  a hammer,  since  it  enlarges  at  its  right  extremity, 
from  whence  proceeds  an  inferior  prolongation,  which  embraces  the 
duodenum  posteriorly,  and  on  the  left,  and  even  a little  forward.  The 
lower  prolongation  is  called  the  /read,  and  the  transverse  larger  portion 
the  tail. 

§ 2236.  The  pancreas  is  attached  to  the  adjacent  parts  by  a very 
loose  cellular  tissue,  and  enveloped  by  a thick  layer  of  the  same  ; it 
has  no  special  capsule.  We  also  distinguish  through  the  cellular  en- 
velop, the  lobes  which  unite  to  form  it. 

These  lobes  can  be  divided  into  extremely  minute  lobules,  attached 
by  a very  loose  cellular  tissue. 

The  pancreas  is  yellowish  brown,  and  rather  firm  in  its  texture. 

§ 2237.  A considerable  excretory  duct  passes  entirely  through  this 
organ  ; it  is  white  and  solid,  and  is  called  the  pancreatic  canal  (ductus 
pancreaticus) ,(l ) or  the  canal  of  Wirsung  (ductus  TVirsungianus). 
This  canal  arises  at  its  posterior  extremity  by  the  union  of  several 
branches,  which  anastomose  at  an  acute  angle.  In  its  course  it  re- 
ceives at  a right  angle,  both  above  and  below,  a considerable  number 
of  other  branches,  which  may  be  easily  followed  by  smaller  granula- 
tions, so  that  it  gradually  increases  in  volume,  and  finally  becomes  a 
line  and  a half  in  diameter.  Just  before  quitting  the  gland,  it  also  re- 
ceives one  or  more  very  large  twigs,  which  arise  from  the  head,  and 
which  also  open  separately  into  the  duodenum. 

This  canal  is  not  visible  on  the  surface  of  the  gland,  which  must  be 
cut  across  in  order  to  see  it. 

(1)  Brunner,  Exp.  nova  circa  pancreas , Amsterdam,  1638. — Graaf,  Dc  succo  pan- 
creaiico,  Leyden,  1664. — Johrenius,  Dc  affect,  hypoehondriacis , Rinteln,  1678.—.). 
M.  Hoffmann,  Dc  panercale,  Altdorf,  1706.— J.  D.  Santorini,  Tabula:  scptcmdccim, 
tab.  xiii. 

(2)  J.  G.  Wirsung',  Figura  ductus  cujusdam,  cum  multiplicibus  suis  ramulis ■ 
novitcr injiancrcatc,  in diversia corporibus  humanis observati,  Padua,  1643. 


OP  THE  DIGESTIVE  SYSTEM. 


317 


It  generally  opens  into  the  duodenum,  three  or  four  inches  below 
the  pylorus,  but  sometimes  much  lower  down,  and  even  ten  inches 
from  it. 

In  the  place  where  it  communicates  with  the  duodenum,  it  unites 
externally  with  the  ductus  choledochus,  but  the  two  cavities  remain 
perfectly  distinct,  even  when  proceeding  side  by  side  through  the  mem- 
branes of  the  intestine.  They  open  side  by  side  near  the  pancreatic 
duct,  a little  to  the  left  of  the  choledochus,  at  the  base  of  a small  cavity 
about  two  lines  long,  the  membrane  of  which  has  all  the  characters  of 
the  inner  tunic  of  the  duodenum,  so  that  we  cannot  properly  consider 
them  as  having  a common  orifice. 

Near  its  orifice  the  excretory  duct  of  the  pancreas  enlarges  more  or 
less,  but  contracts  at  its  opening,  although  there  is  no  fold  similar  to  a 
valve  in  this  or  in  any  other  part.  The  appearance  of  a valve  at  its 
opening  depends  only  on  the  septum  between  it  and  that  of  the  ductus 
choledochus. 

§ 2238.  The  pancreas,  like  all  the  salivary  glands,  and  most  of  the 
glandular  organs,  is  more  developed  in  the  early  periods  of  life  than 
subsequently. 

We  have  observed  that  its  excretory  duct  very  constantly  presents 
a remarkable  difference,  as  it  is  at  first  double,  that  is,  beside  the 
permanent  valve,  there  is  then  a second,  which  opens  separately  into 
the  duodenum.(l) 

§ 2239.  The  congenital  anomalies  of  this  gland  extend  principally 
to  the  arrangement  of  its  excretory  duct,  which  sometimes  seems 
double  ; this  state  must  be  considered  as  a permanence  of  that  in  the 
fetus.  (2) 

The  most  remarkable  consecutive  anomalies  are  induration  and  hy- 
pertrophy. We  more  rarely  find  in  its  excretory  duct,  calculi, (3) 
composed  of  phosphate  of  lime  and  of  an  animal  substance. 

III.  SPLEEN. 

A.  PERFECT  STATE. 

§ 2240.  The  spleen  ( splen , lien)( 4)  is  situated  in  the  left  hypochon- 
drium,  between  the  great  cul-de-sac  of  the  stomach,  the  lumbar  portion 

(1)  Meckel,  Abhandlungen,  p.  331,  353,  366,  380. 

(2)  Tiedemann,  Sur  les  différences  que  le  canal  excreteur  du  pancreas  presente 
dans  l'homme  et  dans  les  mammifères  ; in  the  Journ.  compl.  des  sc.  méd.,  vol.  iv.  p. 
370. 

(3)  Baillie  has  figured  a remarkable  case  of  it.  ( Engravings , fasc.  v.  tab.  vii.) 

(4)  F.  Schuyl,  Dénatura  etusulienis,  Leyden,  1664. — Malpighi,  I)e  liene  ; in  De 
structura  viscerum. — C.  Drelincourt,  Dc  licnosis,  Leyden,  1693. — G.  Stukcley,  The 
spleen , its  description , uses , and  diseases,  London,  1723. — J.  G.  Duvernoi,  De  liene  ; 
in  the  Comm.  Petrop.,  vol.  vi.  p.  156. — S.  T.  Quellmalz,  De  liene,  Leipsic,  1748. — C. 
L.  Rolof , De  fabrica  et  functions  lienis,  Frankfort,  1750. — Lasson  e,  Histoire  anatir 
mique  de  la  rale  ; in  the  Mém.  de  Paris,  1754. — Werlhof,  De  splenis  usu,  Wolfenbuttel, 
1761. — J.  F.  Lobstein,  De  liene , Strasburg,  1774. — J,  P,  P.  Assolant,  Recherches  sur 

Vol.  HI.  41 


31S 


DESCRIPTIVE  ANATOMY. 


of  the  diaphragm,  the  commencement  of  the  descending  colon,  and  the 
left  renal  capsule,  which  it  covers  anteriorly.  Its  form  is  elliptical  ; its 
posterior  or  external  face  is  convex  ; the  anterior  or  internal  is  con- 
cave, and  divided  by  a longitudinal  groove  called  the  fissure  of  the 
spleen  ( hylus  lienalis),  into  two  halves,  an  anterior,  which  is  the  larger, 
and  a posterior.  Its  upper  extremity  is  a little  thicker  than  the  lower  ; 
a fold  of  the  peritoneum  unites  it  to  the  diaphragm,  the  stomach,  and 
the  descending  colon. 

It  varies  much  in  size,  not  only  in  different  individuals,  but  also  in 
the  same  individual  at  different  periods,  and  inconstantly.  In  general 
we  may  say,  that  in  the  adult  it  is  about  four  inches  long,  three  broad, 
and  a little  less  than  one  thick. 

Its  weight  varies  as  much  as  its  size.  Its  mean  weight  is  eight 
ounces,  so  that  in  the  adult  it  is  to  that  of  the  whole  body  as  I : 210. 
But  the  volume  and  the  weight  of  this  organ  are  not  necessarily  in 
an  inverse  ratio  with  the  distension  of  the  stomach,  as  has  been 
asserted. (1)  Its  specific  gravity,  compared  with  that  of  distilled  water, 
is  as  1.200  : 1000. 

It  is  of  a brighter  or  darker  red. 

The  consistence  of  the  spleen  is  slight  ; it  is  also  very  soft. 

§ 2241.  At  first  view  the  spleen  seems  formed  entirely  of  blood-ves- 
sels, of  which  the  arteries  come  from  the  cœliac  trunk  and  the  veins 
rest  directly  on  the  surface  of  the  artery,  and  are  proportionally  larger 
than  in  any  other  part  of  the  body  ; they  empty  into  the  vena-portae, 
and  carry  there  a very  dark  blood.  The  substance  of  the  organ  is  sur- 
rounded by  a very  firm  sero-fibrous  membrane.  The  external  layer 
is  serous  and  comes  from  the  peritoneum,  with  which  it  is  continuous 
by  two  prolongations  mentioned  above. 

The  fibrous  layer  belongs  properly  to  the  spleen,  but  it  can  be  se- 
parated from  the  serous  membrane  only  to  a slight  extent  in  the  fis- 
sure. 

Numerous  layers  and  very  minute  solid  fibres  proceed  from  it,  which 
interlace  in  many  different  ways,  and  enter  the  space  circumscribed  by 
the  capsule,  leaving  between  them  irregular  spaces,  in  which  the 
splenic  vessels  are  distributed. 

These  productions  form,  properly  speaking,  the  base  of  the  tissue  of 
the  spleen. 

Beside  these  fibres,  other  hollow  canals  proceed  from  the  inner  mem- 
brane of  the  spleen  to  its  fissure  ; these  closely  envelop  the  vessels, 
and  unite  with  them.  The  first  filaments  are  attached  to  the  outer 

la  rate,  Paris,  1801.— A.  Morcschi,->SW  vero  eprimario  usu  della  milza,  Milan,  1803. 
— E.  Home,  On  the  structure  and  use  of  the  spleen  ; in  the  Phil,  trans.,  1808. — C.  F. 
Heusinger,  Ueberd.cn  Bäu  und  Verrichtung  der  Milz , Thionvillc,  1817.— F.  Gell- 
haus, Inaugural  Abhandlung  über  den  Nutzent  der  Milz, 'Wurzburg,  1817.— G.  M. 
Felici,  Osservazioni  fisiologiche  sopra  lefunzioni  della  milza,  Milan,  1818. — I.  Deel- 
linger,  Betrachtungen  über  die  Milz  ; in  the  Deutsches  Archiv  für  d.ie  Physiologie, 
vol.  vi.  p.  155.— Jæckel,  Etwas  über  die  Verrichtung  der  Milz  ; same  journal,  vol.  vi. 
pi.  581.— Hodgkin,  Sur  les  fonctions  de  la  rate;  in  the  Journ.  com.pl.  des  sc.  méd.,  vol. 
xiv.  p.  89. — Home,  in  the  Phil.  Irans.,  1821,  p.  25. 

(1)  Assolant,  loc.  cit.,  p.  129-133. 


OF  THE  DIGESTIVE  SYSTEM. 


319 


face  of  these  canals  in  the  same  manner  as  to  the  inner  face  of  the 
fibrous  capsule. 

The  splenic  arteries  give  off  in  their  course  numerous  branches, 
which  divide  into  very  minute  ramuscules,  arranged  like  the  bristles  of 
a brush,  but  they  do  not  anastomose  together.  On  the  contrary,  the 
veins  which  surround  these  arterial  fasciculi,  frequently  anastomose 
with  each  other,  and  with  the  adjacent  veins.  There  are,  however, 
no  great  communications  between  the  arteries  or  the  veins  of  the  dif- 
ferent regions  of  the  spleen.  Those  between  the  veins  and  arteries  are 
very  large,  as  may  easily  be  seen  by  the  aid  of  a microscope,  or  by  the 
facility  with  which  injections  pass  from  the  arteries  into  the  veins. 

Besides  the  blood-vessels,  the  spleen  also  possesses  numerous  lym- 
phatics. Its  nerves  come  from  the  splenic  plexus,  and  are  very  small. 
They  are  scarcely  one  twelfth  as  large  as  the  arteries  they  surround, 
and  we  cannot  trace  them  far  within  the  organ.  Beside  these  consti- 
tuent parts,  which  several  anatomists  assert  are  the  only  ones, 
the  spleen  also  contains,  according  to  the  more  correct  observations  of 
others,  particularly  Malpighi,  Hewson,  Dupuytren,  Home,  Heusin- 
ger,  and  Meckel,  very  many  rounded,  whitish,  and  very  probably 
hollow,  or  at  least  veiy  soft  corpuscles,  which  differ  much  in  respect 
to  size  and  situation  ; their  size  varies  from  one  sixth  of  a line  to  one 
line,  and  they  are  sometimes  near,  and  sometimes  rather  distant 
apart.  « 

These  corpuseles  are  very  intimately  connected  wtth  the  rest  of  the 
tissue  of  the  spleen,  and  receive  many  blood-vessels;  according  to 
Home’s  observations,  confirmed  by  those  of  Heusinger  and  our  own, 
they  swell  much  in  animals  when  they  drink. 

Malpighi  considers  them  as  glands.  Ruysch  and  several  other  ana- 
tomists have  denied  their  existence,  and  have  asserted,  but  wrongly, 
that  they  are  only  simple  fasciculi  of  vessels. 

Although  neither  these  corpuscles,  nor  the  spleen,  have  excretory 
ducts,  they  very  probably  contribute  much  to  the  changes  of  the  blood 
in  passing  through  this  organ,  and  assist  in  forming  the  gastric  juice, 
but  particularly  the  bile. 

The  substance  of  a reddish  brown,  easily  separated  by  washing  and 
pressure,  should  be  regarded  not  as  a constituent  part  of  the  spleen, 
but  as  the  blood  changed  by  this  organ. 

The  cellules  heretofore  admitted  in  the  spleen,  were  very  probably 
produced  by  the  destruction  of  a part  of  the  vessels,  and  of  the  internal 
fibrous  tissue,  by  injections  made  with  too  much  force,  whence  were 
formed  spaces  which  are  afterwards  distended  by  inflation. 

§ 2242.  As  the  spleen  has  no  excretory  duct,  its  functions  are  very 
obscure,  and  the  more  so,  as  it  has  frequently  been  extirpated  without 
producing  any  constant  or  very  great  derangement  in  any  function. 
Even  at  present,  after  so  many  experiments  infinitely  varied,  after  so 
many  observations  and  reflections,  we  can  only  hazard  conjectures  on 
this  subject.  We  may,  however,  conclude  from  facts  hitherto  known, 


320 


DESCRIPTIVE  ANATOMY. 


that  the  spleen  is  intimately  connected  with  the  functions  of  the  liver 
and  stomach,  and  acts  in  concert  with  these  two  organs. 

That  it  assists  in  the  functions  of  the  liver,  is  proved  by  the  fact, 
that  all  the  blood  which  passes  through  its  tissue,  is  carried  to  this 
organ  by  the  trunk  of  the  vena  -portée.  Hence,  we  may  conjecture, 
and  very  probably,  that  the  blood  is  changed  within  it,  and  rendered 
more  proper  for  the  secretion  of  bile,  which  conjecture  is  not  contra- 
dicted by  chemical  experiments,  from  whence  it  has  been  concluded, 
that  the  blood  of  the  splenic  veins  does  not  differ  from  that  in  the  other 
veins.  Possibly,  also,  the  spleen  contributes  mechanically  to  increase 
the  secretion  of  bile,  since,  during  abstinence,  a greater  or  less  quantity 
of  blood  collects  there,  which  is  afterwards  expelled  by  the  pressure  of 
the  stomach  when  filled  with  food,  and  then  goes  toward  the  liver. 
But  as  the  blood  is  not  merely  circulated  in  the  spleen,  but  there  under- 
goes some  change,  it  follows,  that  the  relation  is  not  mechanical  only, 
but  also  chemical. 

The  spleen  receives  less  blood  at  the  commencement  of  digestion, 
because  the  stomach,  which  is  then  full,  prevents  the  blood  from  flow- 
ing freely  into  it  ; but  in  proportion  as  the  contents  of  the  stomach  pass 
out  from  it,  the  blood  flows  more  easily  to  the  spleen,  and  the  function 
of  this  latter,  in  regard  to  the  . liver,  becomes  more  active.  Probably 
also  the  spleen  concurs  in  the  accessory  function  attributed  above  to 
the  liver,  that  of  neutralizing  and  assimilating  foreign  substances  in- 
troduced into  the  body.  Hence  we  must  consider  it  as  a viscus  which 
performs,  in  regard  to  the  vascular  s3rstem,  particularly  to  the  liver, 
the  same  part  as  the  conglobate  glands  towards  the  lymphatic  system. 
It  is  more  analogous  to  these  glands  than  to  the  liver,  as  it  has  no 
excretory  duct.  The  liver  then  appears  as  an  organ  composed  of  a 
conglomerate  and  a conglobate  gland  in  the  vascular  system. 

The  action  of  the  spleen  may  also  relate  to  that  of  the  stomach  in 
several  different  respects  : 

1st.  In  a dynamical  respect,  since  the  two  organs  seem  to  be  op- 
posed to  each  other,  and  the  soft  and  blackish  spleen  may  be  consi- 
dered, from  its  substance  and  the  change  of  the  blood  which  passes 
through  it,  as  contributing  particularly  to  produce  hydrogen,  while 
the  stomach  is  an  organ  which,  from  the  nature  of  its  secreted  fluid, 
tends  particularly  to  produce  oxygen. 

2d.  In  a mechanical  respect,  as  the  spleen  attracts  the  blood  to  it 
when  digestion  is  not  guing  on,  while  it  receives  less  when  this  viscus 
is  full,  so  that  the  blood  flows  in  greater  quantity  toward  the  latter, 
that  is,  precisely  at  the  period  when  most  necessary  to  the  secretion 
of  the  gastric  juice. 

The  function  of  the  spleen  seems  also  to  be  to  receive  promptly  at 
least  a part  of  the  liquids  introduced  into  the  stomach,  although  this 
function  does  not  belong  exclusively  to  it,  since  after  it  has  been  extir- 
pated the  liquids  disappear  as  quickly  as  before,  and  the  substances 
contained  in  this  viscus  reappear  in  certain  fluids. 


OF  THE  DIGESTIVE  SYSTEM, 


321 


B.  DIFFERENCES  DEPENDING  ON  DEVELOPMENT. 

§ 2243.  At  first  the  spleen  does  not  exist.  It  begins  to  appear  dis- 
tinctly during  the  second  month  of  gestation. 

It  is  at  first  infinitely  smaller  in  proportion  to  the  bod}7,  and  parti- 
cularly to  the  liver,  than  it  is  subsequently,  although  it  wrinkles  and 
also  wastes  in  old  age. 

The  whitish  corpuscles  are  proportionally  larger  and  more  visible 
during  the  latter  periods  of  fetal  existence  and  in  infancy  than  during 
the  successive  periods. 

All  these  peculiarities  are  very  important,  as  they  support  the  eighth 
law  established  in  our  introduction.  In  fact  the  spleen  does  not  exist 
in  the  mollusca  which  have  a liver  ; it  becomes  proportionally  smaller 
and  smaller  as  we  descend  from  the  mammalia  toward  the  lower 
classes  of  the  animal  kingdom  ; and  in  most  mammalia,  as  also  in 
several  other  animals,  the  corpuscles  are  regularly  larger  in  proportion 
than  in  man. 


c.  abnormal  state. 

<5  2244.  Among  the  anomalies  of  the  spleen  we  must  distinguish 
particularly  some  deviations  of  formation,(l)  which  deserve  to  be  no- 
ticed. 

This  organ  is  very  rarely  deficient  from  a primitive  deviation  of  forma- 
tion in  a subject  where  the  formation  is  otherwise  normal,  while  it  is 
generally  absent  in  cases  of  acephalia  vera. 

A deviation  of  formation  almost  peculiar  to  the  spleen,  or  at  least 
observed  in  it  more  frequently  than  in  any  other  organ,  is  its  division 
into  several  spleens  termed  accessory  ( licnculi , s.  lienes  accessorii). 
These  accessory  bodies  are  always  situated  on  the  inner  face,  and 
generally  toward  the  lower  extremity  of  the  spleen. 

They  are  usually,  but  not  always,  rounded,  and  vary  in  number 
from  one  to  twenty-three.  The  latter  number,  however,  has  been  ob- 
served only  once,  and  we  rarely  find  more  than  one  supernumerary 
spleen. 

The  great  number  of  these  accessory  spleens  is  usually  attended 
with  other  deviations  of  formation.  This  occurred  in  a subject  who 
had  twenty-three. (2)  In  another  case,  where  there  were  seven,  all 
the  organs  of  vegetative  life  were  at  the  same  time  inverted. (3)  In  a 

(1)  C.  S.  Heusinger,  Mémoire  sur  les  monstruosités  de  la  rate  produites  par  le 
défaut  de  développement  de  ce  viscère  ; in  the  Journ.  compl.  des  sc.  méd.,  vol,  x., 

p.  216. 

(2)  Otto,  Handbuch  der  pathologischen  Anatomie , p.  302. 

(3)  Heusinger,  loc.  cit.t  p.  62. 


322 


DESCRIPTIVE  ANATOMY. 


third,  where  there  were  four,  the  foramen  ovale  of  the  heart  was  open 
to  some  extent.(l) 

The  accessory  spleens  vary  much  in  size. 

The  existence  of  a great  number  of  fissures  which  are  frequently 
very  deep  on  the  anterior  edge  of  the  spleen,  particularly  toward  its 
lower  extremity,  or  of  a more  or  less  distinct  transverse  fissure,  which 
passes  over  its  whole  external  face,  form  a remarkable  intermediate 
degree  between  this  anomaly  and  the  normal  state. 

Among  the  accidental  deviations  of  formation,  one  consists  in  an 
enlargement  of  the  spleen,  usually  attended  with  induration,  which 
commonly  arises  from  the  metastasis  of  a general  disease.  (2) 

We  not  unfrequently  find  the  spleen  unusually  hard  withour  en- 
largement or  very  soft.  The  latter  exists  particularly  in  diseases 
attended  with  great  debility. 

New  formations  are  rarely  developed  in  the  spleen.  The  tubercles 
sometimes  seen  in  it  are  probably  white  corpuscles  somewhat  enlarged. 
Perhaps  we  should  consider  a special  formation  a solid  uneven  yel- 
lowish white  mass  which  is  frequently  developed  in  the  spleen.  It, 
however,  seems  to  be  very  similar  to  fungus  liæmatodes. 

The  capsule  of  the  spleen  frequently  ossifies,  particularly  in  ad- 
vanced age,  to  such  an  extent  even  that  when  the  osseous  substance 
has  acquired  a certain  thickness  in  proportion  to  which  the  organ 
always  wastes,  we  are  led  to  think  that  the  spleen  itself  is  changed 
into  bone. 


ARTICLE  FIFTH. 

VESSELS  AND  NERVES  OF  THE  ABDOMINAL  PORTION  OF  THE 
DIGESTIVE  ORGANS. 

§ 2245.  The  vessels  of  the  most  important  and  the  largest  part  of 
the  digestive  organs  mostly  arise  from  three  trunks,  the  cceliac,  and 
the  superior  and  inferior  mesenteric  arteries,  which  come  directly  from 
the  abdominal  aorta,  and  anastomose  very  frequently  together.  The 
lower  extremity  of  the  rectum  also  receives  some  branches  from  the 
hypogastric  artery. 

The  veins,  if  we  except  those  of  the  lower  part  of  the  rectum  which 
empty  into  the  iliac  veins,  unite  and  form  the  vena-portae,  so  that  all 
the  blood  that  returns  from  these  organs  passes  through  the  liver  be- 
fore going  to  the  heart,  and  from  thence  into  the  lungs. 

(1)  Baillie,  Phil.  Irans.,  vol.  lxxviii.,  p.  350. 

(2)  C.  F.  Heusinger,  Ueber  dir,  Entzündung  und  Vergrosscrung  der  Milz, 
Eisenach,  1820. — S.  Grotlanelli,  Ad  acuta:  et  ceronica:  splenüidis  h.istoriam  animad- 
versioncs,  Florence,  1821. — C.  11.  Schmid,  Cummcnlatiu  de  palhulogiû  lienis,  Got- 
tingen, 1816. 


OF  THE  ORGANS  OF  VOICE. 


323 


The  nerves  come  principally  from  the  great  sympathetic  nerve. 
Those  of  the  stomach,  however,  arise  chiefly  from  the  pne.umo-gastric 
nerve,  and  those  of  the  rectum  from  the  sacral  pairs. 


CHAPTER  II. 

ORGANS  OF  VOICE  AND  RESPIRATION. 

§ 2246.  In  the  preceding  chapter  on  the  systems  we  described  the 
digestive  organs  which  belong  to  vegetative  life  ; these  appear  earliest 
in  animals,  or  in  the  fetuses  of  animals,  perform  at  first  the  functions 
of  all  the  rest,  and  are  the  type  on  which  these  latter  are  formed,  which 
are,  however,  less  perfect  and  much  less  complex.  We  now  proceed 
to  describe  the  respiratory  organs,  in  which  the  nutritious  fluid  formed 
in  the  first  is  in  general  perfected. 

The  vocal  apparatus  is  so  connected  with  the  organs  of  respiration 
that  it  occupies  the  summit  of  the  canal  by  which  these  latter  commu- 
nicate with  the  air  by  the  cavities  of  the  nose  and  mouth,  and  it  is  in 
fact  only  a development  of  the  upper  extremity  of  this  canal.  It  is 
then  most  convenient  to  begin  with  it. 


ARTICLE  FIRST. 

ORGANS  OF  VOICE. 

§ 2247.  The  organs  of  voice(l)  are  composed  principally  of  the 
larynx,  in  which  the  voice  is  formed,  although  it  is  modified  in  differ- 
ent modes  when  passing  through  the  cavities  of  the  nose  and  mouth, 
which  are  situated  before  it. 

I.  LARYNX  GENERALLY  IN  THE  PERFECT  STATE. 

§ 224S.  The  larynx  is  an  oblong,  quadrangular  cavity,  formed  of 
several  cartilages,  of  ligaments  which  unite  them,  of  muscles  which 

(1)  Galen,  Vocalium  instrumentorum  disscctio:  in  the  Opp.  omn. — Fabricius  of 
Aquapendente,  De  visione,  voce,  etauditu:  Id.,  De  laryngé  vocis  instrumenta:  in  the 
Opp.  omn.^—3.  Casserio,  De  vocis  auditusqvc  organis , Ferrare,  1600. — D.  Santorini, 
De  laryngé  : in  the  Obs.  anat.,  c.  vi. — A.  F.  Walther,  De  laryngé  et  voce , Leipsic, 
1740.— R.  A.  Vogel,  De  laryngé  humano  et  rocis  formatione,  Erfurt,  1747.— J.  G. 
Runge,  De  voce  ejusque  organis,  Leyden,  1753. — Hérissant,  Recherches  sur  les  or- 
ganes de  la  voix  des  quadrupèdes  et  de  celle  des  oiseaux  : in  the  Mêvti.  de  Daris , 
1753.— J.  M.  Busch,  De  mec/ianismo  organi  vocis  hujusque  functione,  Groningen, 
1 770. — Vicq-d’Azyr,  De  la  structure  des  organes  qui  servent  à la  formation  de  la 
voix,  considérée  dans  l'homme  et  dans  les  différentes  classes  d’animaux  : in  the 
Mém.  de  Paris,  1779,  p.  178-206.— J,  WolfT,  Diss.  de  organo  vocis  mammalium, 
Berlin,  1812. 


324 


DESCRIPTIVE  ANATOMY. 


move  them,  and  of  a mucous  membrane  which  covers  them  in  every 
part,  after  which  it  is  continuous  upward  with  the  buccal  membrane, 
below  with  that  of  the  trachea.  This  cavity  gradually  contracts  a 
little  from  above  downward.  It  is  situated  at  the  upper  and  anterior 
part  of  the  neck,  below  and  behind  the  lower  jaw,  between  the  trachea 
and  the  cavities  of  the  nose  and  mouth,  of  which  it  is  the  direct  conti- 
nuation. 

A.  CARTILAGES  OF  THE  LARYNX. 

§ 2249.  There  are  nine  cartilages  which  form  the  base  of  the 
larynx,  three  of  which  are  unmated  and  six  exist  in  pairs.  The  pairs 
are  situated  on  the  sides  ; the  unmated  are  divided  by  the  median  line 
into  two  equal  halves,  a right  and  a left. 

The  unmated  cartilages  are  the  largest,  and  principally  form  the 
whole  larynx.  They  are  the  thyroid  and  cricoid  cartilages,  and  the 
epiglottis.  The  pairs  are  the  arytenoid , the  rounded , or  the  tubercles 
of  Santorini , and  the  cuneiform  cartilages. 

I.  THYROID  CARTILAGE. 

§ 2250.  The  thyroid  cartilage  (C.  thyroidca ),  the  largest  of  the  car- 
tilages of  the  larynx,  forms  its  upper  and  anterior  part,  produces  at  the 
upper  part  of  the  neck,  a prominence  called  Adam's  apple.  It  is  an  ob- 
long quadrilateral  plate,  more  broad  than  high,  and  composed  of  two 
lateral  halves,  which  unite  forward  on  the  median  line,  where  the  angle 
they  form  is  more  acute  in  the  male  than  in  the  female.  Hence  this 
layer  is  very  convex  forward  and  very  concave  backward,  where  it  is 
open. 

Its  upper  edge  is  very  convex  ; it  however  presents  in  its  centre  a 
deep  groove,  so  that  the  cartilage  is  lower  in  this  place. 

Its  lower  edge  is  very  convex  : it  is  formed  on  each  side  of  two 
superficial  grooves,  separated  by  a median  prominence. 

The  posterior  edges  are  loose  ; they  extend  upward  and  downward 
into  two  elongated  horns,  which  are  rounded  and  turned  backward, 
and  which  are  distinguished  into  upper  and  lower.  The  upper  horns 
are  longer  and  thinner  than  the  lower. 

We  observe  on  the  outer  face  of  the  cartilage  at  the  base  of  the 
upper  horn  a considerable  triangular  prominence,  whence  arises  an 
oblique  line  which  descends  from  behind  forward  to  the  lower  edge, 
and  which  separates  the  posterior  sixth  of  each  half  of  this  external 
face  of  the  five  anterior  sixths. 


OF  THE  ORGANS  OF  VOICE. 


325 


II.  CRICOID  CARTILAGES. 

§ 2251.  The  cricoid  cartilage  (C.  cricoidea,  s.  annularis ),  which 
forms  the  lower  part  and  a portion  of  the  posterior  part  of  the  larynx,  is 
circular,  as  its  name  indicates,  and  about  three  times  higher  posteriorly 
than  anteriorly.  It  is  convex  forward,  and  on  the  sides  are  depres- 
sions which  render  the  surface  corrugated,  and  on  its  upper  edge  is  a 
sharp  prominence  which  inclines  outward. 

The  posterior  part  is  irregularly  quadrilateral  and  broader  below 
than  above.  Its  anterior  face  is  uniformly  concave  ; the  posterior  is 
loose  and  very  prominent  in  the  centre,  especially  below. 

We  there  observe  a depression  on  each  side,  and  it  presents  a plane 
articular  facet  where  it  unites  with  the  side. 

Its  upper  edge  also  enlarges  on  each  side  into  a plane  articular  facet 
which  is  inclined  from  above  downward. 

III.  ARYTENOID  CARTILAGES. 

§ 2252.  The  arytenoid , triangular , or  pyramidal  cartilages  (C.  ary- 
tœnoideœ , s.  triquelrœ , s.  pyramidales ) have  an  elongated  triangular 
form.  Their  anterior  face  is  convex  and  uneven,  and  divided  by  a 
transverse  prominence  into  a superior  and  an  inferior  depression. 

The  posterior  has  about  the  same  extent  as  the  anterior,  and  is 
concave.  The  internal  is  much  smaller  than  the  other  two,  and  is 
slightly  convex. 

These  two  cartilages  are  fitted  by  their  concave  base  to  the  sides  of 
the  upper  articular  facets  of  the  cricoid  cartilage  (§  2251). 

IV.  ROUND  CARTILAGES. 

§ 2253.  On  the  summit  of  each  arytenoid  cartilage  is  a much 
smaller,  and  also  triangular  cartilage,  termed  the  tubercle  of  Santorini, 
or  the  round  or  horny  cartilage  (corniculum,  s.  capilulum  Santorinia- 
nwn),(l)  the  convex  face  of  which  looks  forward,  and  the  internal 
backward.  Its  lower  face  is  concave,  rests  on  the  convex  summit  of 
the  preceding,  and  is  articulated  with  it  by  a loose  capsular  ligament, 
some  fibrous  ligaments  of  which  add  to  its  solidity. 

V.  CUNEIFORM  CARTILAGES. 

§ 2254.  The  cuneiform  cartilages  (C.  cunéiformes ) are  slightly 
curved  on  themselves.  Their  bases  are  turned  upward,  and  their  sum- 
mits downward.  They  are  situated  in  the  centre  of  the  membranous 
expansion  extended  between  the  arytenoid  cartilages  and  the  epiglottis. 


VOL  III. 


(1)  Loc.  cit.,  p.  97. 
42 


326 


DESCIUETIVE  ANATOMY. 


VI.  EPIGLOTTIS. 

§ 2255.  The  epiglottis  ( epiglottis , s.  ligula ),  a very  soft  cartilage,  is 
nearly  rhomboidal  ; its  lower  part  is  pointed,  and  terminates  by  a su- 
perficial groove,  and  is  situated  directly  above  the  groove  of  tlie  upper 
edge  of  the  thyroid  cartilage.  Its  length  exceeds  its  breadth,  and  it  is 
much  thinner  from  before  backward  than  in  any  other  direction,  except 
at  its  centre.  It  presents  numerous  openings,  through  which  pene- 
trate small  muciparous  glands,  which  open  on  these  two  faces.  Its 
elasticity,  and  the  ligaments  to  be  described,  cause  it  generally  to  he 
perpendicular,  and  to  rise  towards  the  isthmus  of  the  fauces  : but  the 
weight  of  the  substances  which  pass  on  it,  and  the  action  of  special 
muscles,  depress  it,  so  that  it  covers  the  entrance  of  the  larynx. 

The  epiglottis  prevents  the  entrance  of  foreign  bodies,  especially 
the  food  and  drink,  from  the  cavity  of  the  nose,  and  particularly  the 
mouth,  into  the  larynx.  Although  pathological  observations,  in  regard 
to  the  absence  of  this  cartilage,(l)  and  experiments,  where  deglutition 
has  not  been  impeded  by  removing  the  epiglottis,  when  the  nerves  and 
muscles  of  the  glottis  were  preserved,  while  it  was  very  difficult  when 
these  nerves  were  divided,  the  epiglottis  remaining  entire  ;(2)  although 
all  these  facts(3)  prove  that  the  closing  of  the  glottis  also  partially  con- 
tributes to  prevent  the  food  from  falling  into  the  larynx,  it  does  not  fol- 
low that  the  epiglottis  does  not  fulfill  the  function  attributed  to  it  by 
every  physiologist  since  the  time  of  Aristotle.  This  function,  in  regard 
to  which  we  quote  a lively,  but  perfectly  correct  remark  of  Casscrio,(4) 
has  been  doubted  by  Magendie,  whose  opinion  has  been  contested  by 
Mayer,  from  observations  carefully  made  upon  himself.(5) 

(1) Targioni  Tozzetti,  Prima  raccolta  di  osservazioni,  Florence,  1752.— Magendie, 
Précis  de  physiologie , vol.  ii.  p.  63. 

(2)  Magendie,  Mémoire  sur  l'usage  de  l'épiglotte  dans  la  déglutition,  Paris,  1813. 

(3)  C.  T.  F.  Reichel  ( Diss . de  usu  epiglottidis,  Berlin,  1816)  has  observed,  con- 

trary to  Magendie’s  assertion,  that  removig  the  epiglottis  always  rendered  deglu- 
tition difficult  in  those  animals  where  it  wa3  removed.  On  this  subject,  Rudolphi 
mentions  the  case  of  a man  who  died  of  laryngeal  phthisis,  in  whom  the  epiglot- 
tis was  destroyed  so  that  but  a small  portion  of  its  base  remained.  This  man 
found  it  very  difficult  to  swallow:  he  was  obliged  to  mix  drinks  with  his  food 
to  form  akind  of  pulp,  which  was  introduced  into  the  stomach  with  difficulty.  G. 
Sachse  relates  several  cases,  which  prove  that  deglutition  is  always  very  much  im- 
peded in  laryngeal  phthisis.  (Beiträge  zur  genauem  Kcnntniss  und  Unterschei- 
dung der  Kchlkopfs-und  Lujtrührcnschwindsuchlcn,  Hanover,  1821).  Farther, 
Rudolphi  attributes  to  the  epiglottis  another  use  also  : he  thinks  that  this  cartilage 
serves  also  in  those  animals  who  breathe  through  the  nostrils,  the  mouth  being 
closed,  to  favor  the  entrance  of  the  air  into  the  larynx,  by  presenting  a more  direct 
way  than  through  the  cavity  of  the  mouth.  F.  T. 

(4)  Loc.  cit.,  De  epiglottide,  c.  xvii.,  'Palis  structura , talc  officium,  ut  stupidus 
ille,  vecorsque  did  mereatur,  quern  non  corum  consideratio,  allonilum  quasi,  in  ad- 
mirationem  Dei  rapiat. 

(5)  Ueberdic  Function,  des  Kehldeckels,  in  the  Salzburger  Zeitung,  1814,  vol.  iii. 
p.  156. 


OF  THE  ORSANS  OF  VOICE, 


327 


H.  LIGAMENTS  OF  THE  LARYNX. 

§ 2256.  The  cartilages  of  the  larynx  are  united  with  each  other, 
and  with  the  hyoid  bone  and  trachea,  by  capsules,  fibrous  ligaments, 
and  compact  Cellular  tissue. 

L SPECIAL  LIGAMENTS. 

A.  BETWEEN  THE  THYROID  AND  CRICOID  CARTILAGES. 

§ 2257.  The  thyroid  and  cricoid  cartilages  are  united  by  three  liga- 
ments, a central  or  pyramidal,  and  two  lateral. 

a.  Middle  crico-tbyroid  ligament. 

§ 2258.  The  middle  crico-thyroid  ox  pyramidal  ligament  (L.  conoi- 
deum , s.  thyreo-cricoideum  medium ),  is  short,  fibrous,  strong,  and  trian- 
gular. Its  base  looks  downward,  and  its  blunt  summit  upward.  It 
fills  the  space  between  the  centre  of  the  lower  edge  of  the  thyroid  car- 
tilage, and  that  of  the  upper  edge  of  the  cricoid  cartilage. 

It  prevents  the  cricoid  and  thyroid  cartilages  from  separating  from 
each  other  too  far  upward  and  downward. 

b.  Lateral  tbyro-cricoid  ligament. 

§ 2259.  The  lateral  thyro-cricoid  ligament  (L.  thyreo-cricoideum 
laterale ) is  loose,  composed  of  fibres,  which  are  oblique  from  above 
downward,  and  situated  between  the  lower  horn  of  the  thyroid  carti- 
lage and  the  lower  articular  facet  of  the  cricoid. 

Its  uses  are  the  same  as  those  of  the  preceding.  It  serves,  however, 
also  to  confine  the  motions  of  the  two  cartilages  forward  and  backward. 


B.  LIGAMENTS  BETWEEN  THE  THYROID  CARTILAGES  AND  HYOID  BONE. 

a.  Middle  thyro-hyoid  ligament. 

§ 2260.  The  middle  thyro-hyoid  ligament  ( L . thyreo-hyoideum  me- 
dium) is  a broad  layer  of  compact  cellular  tissue,  which  descends  from 
the  posterior  edge  of  the  body  of  the  hyoid  bone,  to  the  middle  groove 
of  the  upper  edge  of  the  thyroid  cartilage. 

b.  Lateral  thyro-hyoid  ligament. 

§ 2261.  The  lateral  thyro-hyoid  \igo.ment  (L.  thyreo-hyoideum  late- 
rale) is  oblong,  rounded,  and  formed  of  longitudinal  fibres.  It  extends 


32S 


DESCRIPTIVE  ANATOMY. 


from  the  summit  of  the  upper  horn  of  the  thyroid  cartilage,  to  the  ex- 
tremity of  the  great  horn  of  the  hyoid  bone.  At  about  its  centre,  but 
generally  nearer  the  upper  than  the  lower  edge,  it  contains  a small 
rounded  and  oblong  cartilage,  or  bone  (C.  tritica),  which,  in  fact,  be- 
longs to  the  class  of  the  cartilages  or  bones  of  the  tendons. 

C.  LIGAMENT  BETWEEN  THE  CRICOID  AND  ARYTENOID  CARTILAGES. 

§ 2262.  Each  arytenoid  cartilage  is  united  by  its  lower  face  to  the 
upper  articular  facet  of  the  cricoid  cartilage,  by  a loose  synovial  cap- 
sule, strengthened  at  intervals  by  ligamentous  fibres. 

D.  LIGAMENT  BETWEEN  THE  ARYTENOID  AND  ROUND  CARTILAGES. 

§ 2263.  These  two  cartilages  are  united  by  a very  loose,  and  often 
slightly  apparent  capsule,  on  the  surface  of  which  pass  ligamentous 
fibres.  • 

I 

E LIGAMENTS  OF  THE  EPIGLOTTIS. 

a.  Epiglotli-byoid  ligament. 

§ 2264.  The  epiglottis  is  united  to  the  upper  edge  of  the  middle 
hyoid  bone  by  a compact  cellular  tissue,  termed  the  epiglotti-hyoid 
ligament  (L.  epiglotti-hyoideum) . 

b.  Thyro-epiglottid  ligament. 

§ 2265.  The  thijro-epiglottid  ligament  (L.  ihyreo-epiglottideum ) is 
strong  and  fibrous.  It  extends  from  the  lower  extremity  of  the  epi- 
glottis to  the  groove  in  the  upper  edge  of  the  thyroid  cartilage. 

F.  LIGAMENTS  BETWEEN  THE  THYROID  AND  ARYTENOID  CARTILAGES. 

§ 2266.  We  find  on  each  side,  between  the  arytenoid  and  thyroid 
cartilages,  one  above  the  other,  two  ligaments,  directed  from  behind 
forward,  from  above  downward,  and  from  without  inward,  which  are 
situated  some  lines  from  each  other,  and  are  termed  the  thyro-arytenoid 
ligaments  (L.  thyreo-cinjlenuidea). 

a.  Inferior  thyro-arytenoid  ligament. 

§ 2267.  The  inferior  thyro-arytenoid  ligament  (L.  thyreo-arytenoi- 
deum  inferius ),  is  much  larger  than  the  upper,  and  is  composed  of  very 
distinct  fibres.  It  extends  from  the  upper  and  prominent  end  of  the 
anterior  edge  of  the  inner  face  of  the  arytenoid  cartilage,  to  the  lower 


OF  THE  ORGANS  OF  VOICE. 


329 


part  of  the  posterior  face  of  the  thyroid  cartilage,  and  is  attached  in 
this  place,  directly  at  the  side  of  its  mate,  above  the  groove  of  the 
lower  edge. 

These  two  ligaments  are  generally  more  developed  in  the  male  than 
in  the  female,  and  are  termed  the  vocal  cords,  or  ligaments  of  the  glot- 
tis ( L . vocalia , s.  glottidis ),  and  the  fissure  between  them  is  termed 
the  glottis  (glottis,  s.  rima  glotlidis). 

b.  Superior  tliyro-arytenoid  ligaments. 

§ 2268.  The  superior  thyro-arytenoid  ligaments  (L.  thyreo-arytenoi- 
deora  superior  um,  s.  vcntricula  laryngis)  are  situated  farther  outward 
and  upward,  between  the  centre  of  the  anterior  face  of  the  arytenoid  car 
tilage,  and  the  angle  of  the  thyroid  cartilage.  Those  of  the  two  sides 
are  more  remote  from  each  other,  are  looser  and  much  less  evidently 
fibrous  than  the  two  preceding.  They  are  distinguished  only  because 
the  mucous  membrane  of  the  larynx  is  reflected  outward,  and  forms  a 
depression  between  them  and  these  latter. 

C.  MUCOUS  MEMBRANE  AND  GLANDS  OF  THE  LARYNX. 

§ 2269.  The  larynx  is  covered  internally  by  a reddish  and  smooth 
mucous  membrane,  which  is  uninterruptedly  continuous  above  with  that 
of  the  cavity  of  the  mouth,  and  below  with  that  of  the  trachea.  The 
outer  face  of  this  membrane  contains  muciparous  glands,  which  vary 
in  size,  and  are  united  in  bundles.  One  of  these  glands,  the  a7'ytenoid 
(G.  arytenoidea),  is  situated  before  the  arytenoid  cartilage.  Another 
is  larger,  imbedded  in  the  midst  of  fat,  and  is  termed  the  epiglottid 
gland  ( G.  epiglottidea ) ; it  occupies  the  space  between  the  epiglottis,  the 
tongue,  and  the  hyoid  bone.  It  opens  by  from  twenty  to  thirty  excre- 
tory passages,  which  pass  through  the  epiglottis,  and  the  origins  of 
which  are  easily  seen  on  the  inner  face  of  the  mucous  membrane  and 
the  epiglottis. 

§ 2270.  The  mucous  membrane  forms  on  each  side  a considerable  de- 
pression, termed  the  ventricle  of  the  larynx  ( ventriculus  laryngis).  This 
depression  is  situated  between  the  superior  and  inferior  thyro-arytenoid 
ligaments  ; it  is  at  most  but  one  line  deep;  and  two  broad.  It  extends 
then  much  farther  from  before  backward,  than  in  any  other  direction, 
It  is  covered  below  by  a considerable  number  of  muciparous  glands. 

D.  MUSCLES  OF  THE  LARYNX. 

§ 2271 . The  muscles  of  the  larynx  are  divided  into  those  which 
move  the  whole  apparatus,  and  those  which  move  some  of  its  carti- 
lages. 


330 


DESCRIPTIVE  ANATOMY. 


I.  GENERAL  MUSCLES  OF  THE  LARYNX. 

§ 2272.  The  general  muscles  of  the  larynx  are  the  sterno-thyroideus 
and  the  hyo-thyroideus. 

a.  Sterno-thyroideus. 

§ 2273.  The  sterno-thyroideus  muscle  (M.  bronchitis ),  is  thin,  ob- 
long, and  considerably  contracted  from  below  upward.  It  arises  from 
the  posterior  face  of  the  handle  of  the  sternum,  and  the  inner  part  of 
the  posterior  face  of  the  cartilage  of  the  first  rib,  ascends  directly  before 
the  trachea,  covered  by  the  sterno-hyoideus  muscle,  and  is  attached 
by  an  oblique  edge,  formed  of  very  short  tendinous  fibres,  to  the  oblique 
line  of  the  thyroid  cartilage.  It  is  generally  blended  at  its  outer  part 
with  the  thyro-hyoideus  muscle,  and  it  is  cleft  in  a greater  or  less 
extent. 

Its  external  face  generally  presents,  some  distance  from  its  lower  ex- 
tremity, a transverse  or  oblique  tendinous  intersection. 

Sometimes  there  are  two  of  these  muscles  placed  one  above  the 
other.(l)  It  depresses  the  larynx,  by  acting  on  the  thyroid  cartilage. 
Its  union  with  the  following  muscle  causes  it  to  depress  the  hyoid 
bone.  . 

b.  llyo-tLiyrokleus. 

§ 2274.  The  hyo-thyroideus  muscle  has  an  oblong  square  form  : it 
gradually  contracts  from  below  upward,  and  at  the  same  time  becomes 
thicker  in  the  same  direction.  It  arises  from  the  oblique  line  of  the 
thyroid  cartilage,  directly  above  the  upper  edge  of  the  preceding,  and 
ascends  along  the  outer  part  of  the  lateral  face  of  the  thyroid  cartilage, 
to  arrive  at  the  great  horn  of  the  hyoid  bone,  and  is  attached  to  the 
anterior  part  of  the  lower  face. 

It  raises  the  thyroid  cartilage  and  the  larynx,  when  the  hyoid  bone 
is  fixed,  and  depresses  it  when  the  latter  is  not  fixed,  so  that  it  con- 
tributes by  the  first  of  these  two  actions,  to  produce  acute  sounds,  and 
by  the  second  to  deglutition. 

II.  SPECIAL  MUSCLES  OF  THE  LARYNX. 

§ 2275.  The  special  muscles  of  the  larynx  are  those  which  dilate 
and  contract  the  glottis. 

A.  MUSCLES  WHICH  DILATE  THE  GLOTTIS. 

a.  Crico-thyroideus. 

§ 2275.  The  crico-thyroideus  muscle  (M.  crico-thyroideus,  s.  dila- 
tator glottidis  anterior ),  is  very  small,  and  nearly  rhomboidal,  and  its 

(1)  Gunz,  Ohs.  anat.,  in  the  Mém.  prés,  a Vac.  des  sc.,  vol.  i.  p.  286. 


or  THE  ORGANS  OF  VOICE. 


331 


figure  is  a slightly  inequilateral  square.  It  is  covered  by  the  sterno- 
thyroideus  muscle,  and  is  situated  between  the  lateral  faces  of  the  thy- 
roid and  the  lower  edge  of  the  cricoid  cartilage.  It  arises  from  the 
lower  edge  and  the  lateral  face  of  this  latter.  Its  fibres  are  directed 
obliquely  from  below  upward,  and  from  before  backward,  and  are  often 
divided  into  two  distinct  fasciculi,  an  anterior  and  a posterior.  It  is 
attached  by  a short  tendon  to  the  lower  edge,  and  the  inferior  horn  of 
the  thyroid  cartilage. 

It  is  used  to  draw  the  sides  of  the  thyroid  cartilage  downward  and 
outward,  so  that  it  enlarges  the  glottis. 

6.  Crico-arytenoideus. 

§ 2277.  The  crico -ary tenoideus  muscle  (AI.  crico-arytcnoides,  s.  dila- 
tator glotlidis  posticus ),  is  rhomboidal,  and  fills  most  of  the  posterior 
face  of  the  cricoid  cartilage.  It  arises  from  its  whole  extent,  ascends 
from  within  outward,  and  is  attached  by  a short  tendon  to  the  outer 
edge  of  the  arytenoid  cartilage. 

It  draws  this  cartilage  outward,  turns  it  a little  on  its  axis,  and  thus 
dilates  the  glottis,  especially  at  its  posterior  part. 

B.  MUSCLES  WHICH  DILATE  THE  GLOTTIS. 

a.  Crico-arytenoideus  lateralis. 

§ 2278.  The  crico-arytenoideus  l at  trails  muscle  is  small,  and  of  an 
elongated  triangular  form.  It  extends  obliquely  from  before  backward, 
and  from  below  upward,  from  the  posterior  part  of  the  upper  edge  of 
the  lateral  portion  of  the  cricoid  cartilage,  to  the  lower  part  of  the  outer 
face  of  the  arytenoid  cartilage. 

b.  Arytenoides  obliquus  et  transversus. 

§ 2279.  The  arytenoides  obliquus  and  transversus  muscles  being 
united  very  intimately,  should  be  considered  as  forming  a single  mus- 
cle, the  different  layers  of  which  do  not  follow  the  same  direction. 

The  oblique  fibres  form  the  two  posterior  and  weaker  layers.  They 
arise  from  the  lower  part  of  the  outer  edge  of  the  arytenoid  cartilage, 
above  the  insertion  of  the  crico-arytenoideus  muscle,  ascend  obliquely 
towards  the  opposite  side,  and  becoming  broader  and  thinner,  are 
attached  to  the  outer  edge  of  the  arytenoid  cartilage  of  the  op- 
posite side. 

The  fibres  which  come  from  the  left  arytenoid  cartilage,  usually 
cover  those  arising  from  the  cartilage  of  the  other  side. 

The  transverse  fibres  are  partly  covered  by  the  preceding,  and  are 
attached  by  their  two  edges  to  the  posterior  face  and  the  external  edge 
of  the  two  arytenoid  cartilages. 


332 


DESCRIPTIVE  ANATOMY. 


All  these  fibres  bring  together  forcibly,  the  two  arytenoid  cartilages, 
and  thus  contract 'the  glottis,  especially  at  its  posterior  part,  in  a 
transverse  direction. 


c.  Thyro-arytenoideus. 

§ 2280.  The  thyro-arytenoideus  muscle  (AI.  thyro-arytenoideus)  is 
very  elongated  ; it  arises  from  the  centre  of  the  inner  face  of  the  thy- 
roid cartilage,  from  the  pyramidal  ligament,  sometimes  also  from  the 
lower  part  of  the  epiglottis,  goes  backward  and  a little  upward,  and  is 
inserted  at  the  lower  part  of  the  outer  edge  of  the  arytenoid  cartilage, 
directly  above  the  upper  extremity  of  the  crico-arytenoideus  lateralis 
muscle,  with  which  it  is  blended. 

Sometimes  we  observe,  still  higher,  another  and  smaller  synonymous 
muscle. 

These  two  muscles  draw  the  arytenoid  cartilage  forward,  and  thus 
contract  the  glottis  from  before  backward.  They  diminish  the  extent 
of  the  glottis  more  than  any  other  muscle.  The  fibres  which  go  to 
the  epiglottis,  are  inserted  in  this  cartilage. 

cl.  Thyro-epiglotticus. 

§ 2281.  The  thyro-epiglotticus,  or  the  depressor  cpigloilidis  muscle, 
arises  from  the  centre  of  the  inner  face  of  the  thyroid  cartilage,  and  is 
inserted  on  the  lateral  edge  and  the  lower  part  of  the  epiglottis. 

There  is  sometimes  a smaller  one,  which  arises  farther  inward  and 
upward. 

These  two  muscles  depress  the  epiglottis. 


F.  NERVES  OF  THE  LARYNX. 

§ 2282.  The  nerves  of  the  larynx  arise  from  the  pneumo-gastric 
nerve,  and  are  the  superior  laryngeal  and  the  inferior  laryngeal  or  re- 
current nerve.  Both  are  distributed  in  the  mucous  membrane  and  in 
the  muscles.(l) 

(1)  Magendie  (Physiologie,  vol.  i.,  p.  206)  and  Cloquet  (Traité d' anatomic,  vol.  ii., 
p.  622)  think  the  first  of  these  nerves  goes  wholly  or  nearly  so  to  the  crico-thyroidei 
posticus  and  laterales  muscles,  and  also  to  the  thyro-arytenoideus.  Hence,  whether 
the  different  muscles  contract  or  dilate  the  glottis,  they  receive  all  their  filaments 
from  one  of  these  two  nerves,  and  completely  dividing  or  tying  them,  enfeebles  the 
voice,  which  is  entirely  lost  when  both  are  divided.  Kudolphi  ( Physiologie , vol.  ii., 
p.  376)  remarks  that  this  description  is  incorrect,  and  that  we  must  adopt  that  of 
Andcrsch  and  Scemmcrring,  whose  neurology  is  followed  by  Meckel.  In  fact,  the 
superior  laryngeal  nerve  anastomoses  by  some  twigs  with  the  recurrent  nerve  within 
the  larynx  ; the  two  nerves  send  twigs  also  to  the  muscles  which  contract  and  dilate 
the  glottis,  and  the  recurrent  nerve  sends  some  to  the  crico-thyroideus  muscle.  An- 
dersch  (Tract,  de  nervis  hum.  corp.  aliquibus,  p.  i.,  Koningsberg,  1797,  p.  60)  men- 
tions a case  where  the  two  nerves  did  not  anastomose  in  the  larynx,  but  expressly 


OF  THE  ORGANS  OF  VOICE. 


333 


G.  FUNCTIONS  OF  THE  LARYNX. 

§ 2283.  The  mucous  membrane  of  the  larynx  is  extremely  suscep- 
tible, on  account  of  the  great  number  of  nerves  which  it  receives,  par- 
ticularly in  the  region  of  the  glottis.  This  sensibility  prevents  foreign 
bodies  from  entering  the  trachea,  where  they  would  inevitably  cause 
suffocation.  It  is  curious  that  it  is  so  developed  only  at  the  upper 
paît  of  the  air-passages,  and  that  the  mucous  membrane  of  the  trachea 
does  not  possess  it. 

The  vitality  of  the  larynx  is  manifested  principally  by  its  motions, 
which  are  of  two  kinds.  In  fact  ; 

1st.  They  extend  to  the  whole  system,  or  are  confined  to  some  of 
its  component  parts. 

2d.  They  move  in  several  different  cases,  and  are  connected  with 
several  functions. 

The  general  motions  of  the  larynx  vary  its  relations  with  the  adja- 
cent parts,  according  as  it  is  drawn  upward,  downward,  forward,  or 
backward.  The  partial  motions  change  the  mutual  relations  of  its 
constituent  parts,  and  vary  particularly  the  form  and  extent  of  the 
glottis. 

The  whole  larynx  moves  in  speaking  and  deglutition. 

During  deglutition,  the  larynx  is  drawn  forward  and  upward,  as  we 
have  already  explained,  which  prevents  the  food  from  entering  it. 

In  speaking,  the  larynx  rises  in  acute  sounds,  both  to  raise  the  thy- 
roid from  the  cricoid  cartilage,  and  thus  to  contract  the  glottis,  and  at 
the  same  time  to  tense  its  ligaments,  so  as  to  lengthen  and  contract  the 
trachea.  In  low  tones,  on  the  contrary,  it  is  depressed  to  produce  op- 
posite changes. 

The  partial  motions  are  connected  with  deglutition,  respiration,  and 
speaking. 

In  fact,  in  deglutition,  the  glottis  is  so  contracted  by  the  action  of  its 
constrictor  muscles,  that,  even  were  the  epiglottis  absent,  the  food 
would  not  necessarily  and  constantly  fall  into  the  air  passages. 

In  respiration,  the  glottis  is  dilated  during  inspiration,  and  contracted 
in  expiration  ; these  changes  constantly  occur,  even  when  the  voice 

states  that  this  is  not  the  common'  arrangement.  When  it  may  be  as  true  that  it  is 
not,  says  Rudolphi,  that  the  constrictor  muscles  and  those  which  dilate  the  glottis 
receive  distinct  branches  from  the  par  vagum,  what  must  we  conclude  ? One  nerve 
causes  the  contractions  in  muscles  which  contract  and  those  which  dilate  the  glottis  j 
it  is  then  unimportant  which  these  museles  receive.  But  the  fact  that  the  same 
muscle  receives  twigs  from  the  upper  and  from  the  lower  nerve  is  very  important, 
since  the  action  may  take  place  in  one  direction  when  a ligature  or  section  prevents 
it  in  the  opposite,  and  it  is  still  more  so  as  the  pneumo-gasti  ic  nerve  anastomoses- 
above  and  below  with  the  great  sympathetic  nerve,  and  above  with  the  glosso-pha- 
ryngeal,  the  accessory,  and  the  hypogastric  nerves,  so  that  the  inner  nerves  of  the 
larynx  certainly  come  from  several  different  sources.  F.  T. 


VOL.  III. 


43 


334 


DESCRIPTIVE  ANATOMY. 


cannot  be  formed,  on  account  of  an  opening  in  the  Irachea.(l)  Far- 
ther, this  is  not  surprising,  since  they  coincide  with  analogous  changes 
which  supervene  simultaneously  in  the  trachea,  of  which  the  larynx 
must  be  considered  the  upper  enlarged  and  more  developed  part. 

From  Legallois’  experiments  the  closing  of  the  glottis  is  the  cause 
of  rapid  death  in  suffocation,  which  occurs  in  certain  cases  from  di- 
viding the  pneumo-gastric  nerve  or  the  laryngeal  branch,  particularly 
in  youth,  as  in  such  states  the  glottis  always  appears  very  much  con- 
tracted.^) 

The  fact  is  correct,  but  the  mode  of  explaining  it  by  the  paralysis  of 
the  arytenoidei  muscles  is  only  partially  true.  The  contraction  and 
even  the  closing  of  the  glottis  from  Ihe  paralysis  of  the  muscles  to 
which  the  recurrent  nerve  is  distributed,  seems  to  depend  rather  on  the 
predominance  of  the  muscles,  the  nerves  of  which  are  unaltered,  and 
therefore  caused  only  in  part  by  the  paralysis. 

In  fact  in  animals  of  a certain  age,  in  which  the  operation  is  less 
dangerous  on  account  of  the  size  of  the  glottis,  this  opening  is  almost 
entirely  closed  after  dividing  the  two  recurrent  nerves,  while  it  is  closed 
but  imperfectly  when  the  superior  laryngeal  nerves  are  cut,  and  the 
power  of  forming  it  is  lost  after  separating  all  the  nerves  of  the  la- 
rynx.(3) 

The  special  motions  of  the  larynx  are  very  remarkable  in  forming 
the  voice. 

At  each  tone  the  glottis  contracts,  and  the  more  the  louder  the  tone 
is. (4)  The  contraction  occurs  particularly  from  one  side  to  ihe  other  ; 
sometimes  also  from  before  backward,  and  often  in  every  direction  at 
once. 

§ 2284.  The  larynx  is  the  organ  of  the  voice.  This  is  proved  : 

1st.  By  the  loss  of  voice,  without  any  derangement  in  the  respira- 
tion, when  the  trachea  presents  an  opening  through  which  the  air 
enters  and  emerges  in  inspiration  and  expiration. 

2d.  By  the  diminution  or  the  total  loss  of  voice  when  some  parts  of 
the  larynx,  as  the  vocal  cords  have  been  destroyed,  or  the  arytenoid 
or  cricoid  cartilages,  or  the  laryngeal  nerves  are  divided. 

3d.  By  the  differences  in  the  voice,  dependent  on  those  in  the  ar- 
rangement of  the  parts  of  the  larynx. 

The  voice  is  formed  in  the  glottis,  since  the  power  of  producing  it  is 
lost  when  the  crico-thyroid  ligaments  are  divided,  and  the  removal  of 
the  upper  half  of  the  arytenoid  cartilages  and  the  longitudinal  section 

(1)  Bichat,  Anat.  descript.,  1802,  vol.  ii.,  p.  405. — Legallois,  Exp.  sur  !c  principe  de 
la  rie,  Paris,  1812,  p.  198. — L.  Mende,  Lieber  die  Bewegung  der  Stimmritze  beim 
Athemholen,  eine  neue  Entdeckung  ; mit  beygefügten  Bemerkungen  über  den. 
Nutzen  und  die  Verrichtung  des  Kehldeckels , Gripswald,  1816. 

(2)  Leg'allois,  p.  197. 

(3)  Magendie,  Sur  l’épiglotte,  p.  4. 

(4)  Ferrein  (M ém.  de  Paris,  1741,  p.  559)  has  already  opposed  the  opinion  hitherto 
existing,  viz.  that  the  contrary  is  true.  Bichat  has  followed  in  the  same  track  (Anat. 
dcscr.,  vol.  ii.,  p.  408). 


©F  THE  ORGANS  OF  VOICE. 


335 


of  the  thyroid  cartilage  produces  the  same  effect,  which  is  always  ob- 
served iu  the  contraction  of  the  glottis  in  crying,  as  the  destruction  of 
the  upper  ligaments  has  no  effect  on  the  voice,  and  as  these  ligaments 
likewise  are  always  too  far  from  each  other  to  contract  the  glottis(l) 
transversely. 

§ 2285.  We  have  now  to  determine  how  the  voice  is  formed  in  this 
place.  Some  suppose  it  is  owing  to  the  vibrations  of  the  air,  as  in  a 
wind-instrument. (2)  Others  assert  that  it  is  produced  by  the  vocal 
cords,  as  in  a stringed  instrument.(3)  Finally,  several  have  combined 
these  two  theories. (4) 

The  first  has  been  supported  : 

1st.  By  the  analogy  of  the  air-tube  with  a wind  instrument,  in 
which  the  formation  of  the  different  sounds  is  produced  by  modifying 
the  diameter  of  the  opening. 

2d.  By  the  comparison  with  the  lips,  where  the  same  conditions 
occur. 

3d.  By  different  experiments  proving  : 

a.  That  the  tension  or  relaxation  of  the  vocal  cords  has  no  effect  on 
the  acute  or  grave  character  of  the  sound,  inasmuch  as  the  glottis  is 
dilated  or  contracted  by  them. 

b.  That  when  one  of  the  vocal  cords  is  tense  and  the  other  relaxed, 
they  do  not  produce  two  different  sounds,  but  one  sound,  the  acuteness 
of  which  is  proportional  to  the  breadth  of  the  glottis. 

c.  That  the  tone  does  not  change  when  we  touch  the  vocal  cords. 

d.  That  the  contraction  of  the  glottis  is  sufficient  to  render  the  tone 
more  acute,  and  its  dilatation  to  depress  it,  although  the  tension  of  the 
vocal  cords  does  not  change,  and  independent  too  of  their  form. 

e.  That  the  sound  is  independent  of  the  force  with  which  the  air 
leaves  the  lung. 

f.  That  no  tones  are  formed  when  the  glottis  is  very  much  dilated, 
and  the  vocal  cords  are  very  tense,  and  the  air  is  forcibly  expelled  from 
the  lung.(5) 

(1)  E.  Grasinow  lias  asserted  (Russiche  Jahrbücher,  vol.  ii.,  pt.  i.,  p.  125-143)  that 
the  voice  is  formed  in  the  trachea.  Burdach  has  refuted  this  absurd  opinion  (same 
journal,  p.  153-160). 

(2)  Fabricius  of  Aquapendente,  De  laryngé,  p.  ii.,  c.  iv.  Vocis  opifcx,  causa  seu 
organum  inquiritur. — C.  F.  S.  Liscovius,  Diss.  sistens  theoriam  vocis,  Leipsic,  1814, 
p.  28-37. 

(3)  Ferrein,  De  la  formation  de  la  voix  dans  Vhomme  ; in  the  Mém.  de  Paris.  1 741, 
p.  545. 

(4)  Galien,  De  vsu  partium,  vol.  vii.,  p.  10. — Casserio,  De  laryngé,  book  ii.,  ch. 
xiv.,  De  glottide. — Dodart,  Mém.  sur  les  causes  de  la  voix  de  l'homme  et  de  ses  diffé- 
rens  tons  ; in  the  Mém.  de  Paris,  1700,  p.  308. — Id.,  Supplémens  aux  mémoires  sur 
la  voix  et  sur  les  tons;  same  journal,  1706,  p.  169  and  500;  1707,  p.  83. — Dodart, 
however,  attributes  most  influence  to  the  vibrations  of  the  air  ; it  is  then  difficult  to 
understand  why  modern  physiologists,  even  neglecting  Fabricius  of  Aquapendente, 
should  maintain  that  Ferrein’s  opinion  was  the  only  one  admitted,  ana  present  the 
theory  a3  new,  and  more  so  because  Ferrein  directly  opposes  the  hypothesis  of 
Dodart. 

(5)  Liscovius,  he.  cit.,  p.  29-34. 


33G 


descriptive  anatomy. 


The  second  theory  is  supported  : 

1st.  By  the  analogy  of  the  vocal  cords  with  stringed  instruments^  1) 

2d.  By  experiments  which  have  proved  that  the  extent  to  which  the 
larynx  was  open  had  absolutely  no  effect,  on  the  acute  or  grave  charac- 
ter of  the  sound,(2)  while,  on  the  contrary,  the  tone  became  acute  as 
the  vocal  cords  were  carried  outward  and  extended  by  the  air  leaving 
the  lung,  and  was  lower  when  the  ligaments  were  compressed  ; that  it 
is  modified  in  the  same  manner  when  these  ligaments  are  fixed  on  se- 
veral points  ; that  the  different  tones  are  produced  when  the  degree  of 
tension  of  the  ligaments  varied  ; finally,  that  similar  phenomena  occur 
when  the  ligaments  of  the  larynx  are  entirely  detached,  except  at 
their  tw1 2 3 4 5 6 7 * 9o  extremities,(3) 

Hence,  the  degree  of  openness  of  the  larynx  would  not  cause  a dif- 
ference in  the  sounds,  but  only  in  the  volume  of  the  voice. (4) 

Very  probably  the  third  opinion  is  most  correct,  although  the  experi- 
ments  first  mentioned  prove,  that  the  vibrations  of  the  vocal  cords  con- 
tribute less  to  produce  the  voice  than  those  of  the  air  passing  through 
the  glottis  ; they  occur  simultaneously,  without  being  necessarily  con- 
nected with  speaking,  and  the  more  as  the  larynx  and  trachea  vibrate 
very  evidently  when  the  air  is  blown  in  with  force,  although  the  voice 
js  not  necessarily  produced. (5) 

The  acuteness  of  the  voice  in  the  female  corresponds  very  well  with 
the  narrowness  of  the  glottis,  but  not  with  the  greater  softness  of  the 
vocal  cords. 

§ 2286.  But  although  the  voice  forms  in  the  larynx,  panicularly  in 
the  glottis,  the  parts,  however,  before  this  opening,  the  epiglottis,  the 
cavity  of  the  month,  and  the  nasal  fossæ,  also  assist  to  form  it. 

Doubtless  the  principal  function  of  the  epiglottis  is  to  close  the  la- 
rynx during  deglutition,  but  very  probably  also  it  contributes  to  produce 
the  voice. 

In  fact  Haller  has  refused  to  it,  contrary  to  the  opinion  of  Tam 
\-ry,(6)  and  Santorini, (7)  all  agency  in  phonation,  not  because  it  exists 
before  the  fetus  possesses  a voice, (8)  but  because  this  latter  is  formed 
in  the  larynx,  consequently  below  the  epiglottis,  and  because  birds  sing 
although  deprived  of  it. (9) 

This  view  of  the  subject  is  supported  by  some  experiments,  which 
demonstrate  that  the  force  of  the  voice  does  not  change,  although  we 
cut  transversely  between  the  larynx  and  the  hyoid  bone,  draw  the 

(1)  Ferrein,  p.  566,  560. 

(2)  14.,  p.  559. 

(3)  Fer  roin,  loc.  cil. — Porta],  Exp.  sur  la  voix  ! in  bis  Mémoires , vol.  ii.,  p.  308. 

(4)  Ferroin,  p.  558. 

(5)  Liscovius,  p.  34. 

(6)  Nor.  anal.,  Ulin,  1694,  p.  408. 

(7)  De  laryngé,  § 10. 

(9)  Mayer,  loc.  cil,,  p.  185, 186. 

(9)  Epiglottis  cquidem  nihil  facial  ad  vocem.cum  ea  (rox)  nat.a  sit  el  perfecta 
qua  m primvm  aer  ex  glottidis  rima  prodiit  el  absque  epiglotlide  arcs  suaviseime 
fçijiant  (El  phys.,  ).  ix.,  pt.  i.,  § v.,  p.  572). 


OF  THE  ORGANS  OF  VOICE, 


337 


epiglottis  outward,  and  thus  place  the  glottis  directly  opposite  the 
external  wound  : that  the  removal  of  the  top  of  this  cartilage  has  no 
influence  on  the  voice  generally,(l)  and  that  its  depression,  its  eleva- 
tion, and  even  its  entire  removal,  have  no  effect  on  the  character  of  the 
sounds.(2) 

But  these  facts  only  demonstrate  that  the  epiglottis  is  not  absolutely 
necessary  to  phonation.  Farther,  the  argument  drawn  from  birds 
proves  nothing,  since  their  voice  is  formed  in  a lower  larynx,  and  in 
them  the  epiglottis  may  be  replaced  by  the  whole  trachea  and  by  the 
superior  glottis. 

Finally,  several  observations  and  experiments,  made  with  great  care, 
admit  the  conjecture  that  the  epiglottis  alone,  or  together  with  the  soft 
palate,  contributes  materially  to  the  changes  in  the  volume,  tone,  and 
modulation  of  the  voice, (3)  since  its  situation,  direction,  and  form  ex- 
perience changes  like  those  remarked  in  this  respect  in  the  voice,  and 
we  have  no  authority  for  admitting  that  these  phenomena  result  from 
other  changes  which  occur  in  the  larynx,  an  opinion  probably  pro- 
fessed by  Ferrein,(4)  since  the  new  organ  of  voice  he  maintains  can 
hardly  be  the  soft  palate.(5) 

In  regard  to  the  cavities  of  the  nose  and  mouth  we  may  remark, 
that  the  power  and  clearness  of  the  voice  are  increased  by  its  being 
retained  in  these  two  cavities,  as  is  easily  seen  from  the  difference 
when  the  nose  is  stopped,  or  the  pituitary  membrane  is  swelled. 

Farther,  the  different  inflexions  of  the  voice,  which  are  termed  let- 
ters,(6)  are  produced  both  by  the  larynx  and  the  different  parts  of  the 
oral  cavity. 

The  vowels  are  formed  principally  in  the  canal  included  between  the 
tongue  and  the  palate.  Their  differences  depend  almost  entirely  on 
those  in  the  diameter  of  this  canal,  caused  by  the  motions  of  the 
tongue. 

On  the  contrary,  the  epiglottis  and  the  different  parts  of  the  mouth, 
especially  the  lips  and  the  soft  palate,  have  great  effect  on  the  forma- 
tion of  the  consonants. 

II.  SEXUAL  DIFERENCES  IN  THE  LARYNX. 

§ 2287.  The  larynx  is  one  of  the  organs  which  presents  most  mani- 
festly the  differences  of  sex.  That  of  the  female  is  usually  one  third 
and  sometimes  one  half  smaller  than  that  of  the  male  ; all  its  con- 
stituent cartilages  are  much  thinner  : the  thyroid  cartilage  also  is  even 
flatter,  because  its  two  lateral  halves  unite  at  a less  acute  angle. 

(1)  Bichat,  Anat.  descript.,  vol.  ii.,  p.  402,  404. 

(2)  Liscovius,  p.  34. 

(3)  Mag-endie,  Physiol.,  vol.  i.,  p.  221. — Mayer,  toe.  cit. — Mende,  loc.  cit. 

(4)  JSur  la  formation  de  la  voix  ; in  the  Mem.  de  Paris,  1741,  p.  574. 

(5)  Haller,  loc.  cit.,  p.  455. 

(6)  Kempelen,  Mechanismus  der  menschlichen  Sprache,  nebst  der  Beschreibung 
seiner  sprecaenden  Maschine , Vienna,  1791. 


338 


DESCRIPTIVE  ANATOMY. 


Hence  why  the  larynx  in  the  male  forms  at  the  upper  part  of  the  neck 
a prominence  which  is  not  visible  in  the  female.  From  the  same 
cause  also  the  groove  in  the  upper  edge  is  much  more  superficial  in 
this  latter  than  in  the  male. 

The  glottis  in  the  female  is  much  smaller  than  in  the  male,  and  the 
vocal  cords  are  shorter. 


III.  DIFFERENCES  IN  THE  LARYNX  DEPENDENT  ON  AGE. 

§ 2288.  The  sexual  differences  we  are  about  to  mention  do  not  ap- 
pear until  puberty  : until  then  the  larynx  has  precisely  the  same  form 
in  the  two  sexes,  and  consequently  the  voice  is  nearly  the  same  in 
both.  In  eunuchs  it  is  small  as  in  females.(l) 

This  organ  developes  itself  much  more  slowly  than  other  organs, 
and  not  proportionally  with  them  : it  seems  less  regular  in  respect  to 
its  periods,  so  that  the  larynx  is  sometimes  smaller  in  some  children 
than  in  others  who  are  younger,  although  the  growth  of  the  others 
corresponds  perfectly  to  their  age. 

The  larynx,  especially  the  glottis,  generally  continues  small  for  a 
long  time  ; thus  it  differs  but  slightly  in  a child  of  three  and  one  of 
twelve  years  of  age.  But  the  difference  is  suddenly  so  great  at  the 
period  of  puberty,  that  in  the  course  of  a year  thè  glottis  doubles  in 
breadth  and  length. (2) 

IV.  ABNORMAL  STATE  OF  THE  LARYNX. 

A.  DEVIATIONS  IN  FORMATION. 

§ 2289.  The  whole  larynx  or  some  of  its  parts  rarely  present  pri- 
mitive deviations  of  formation. 

We,  however,  must  mention  here  its  unusual  littleness,  which  de- 
pends on  the  permanence  of  its  primitive  formation,  and  which  coexists 
with  the  destruction  or  imperfect  development  of  the  testicles, (3)  the 
absence  of  the  epiglottis, (4)  the  division  of  this  cartilage, (5)  the  ab- 
sence of  the  upper  horns  of  the  thyroid  cartilage, (6)  of  the  cricoid  and 
the  arytenoid  cartilages, (7)  which  is  very  curious  as  it  establishes 
an  uncommon,  resemblance  between  the  larynx  and  the  trachea  : the 

(1)  Dupuytren,  Hull,  de  la  hoc.  phil, , vol.  ii.,  p.  195. 

(2)  Richerand,  Recherches  sur  la  grandeur  de  la  glotte  et  sur  l’état  de  la  tunique 
vaginale  dans  l'enfance  ; in  the  Mém.  de  la  soc.  méd.  d’émul. , vol.  iii.  p.  326. 

(3)  Dupuytren,  Bull,  de  la  soc.  phil.,  vol.  ii.,  p.  195. — Meckel,  Handbuch  der  patho- 
logischen Anatomie,  vol.  i.,  p.  485. 

(4)  Targioni  Tozzelti,  Prima  raccolta,  Florence,  1752. 

(5)  Meckel,  loc.  cit. 

(G)  Sandifort,  Exerc.  anat.,  1.  ii.,  ch.  vii.,  p.  G4. 

(7)  Roederer,  De  fceluparalylico  ; in  tlic  Comm,  soc.  Gott.,  vol.  iv.,  p.  136. 


OF  THE  ORGANS  OF  VOICE. 


339 


obliquity  and  curve  of  the  epiglottis  ;(  1 ) the  imperfect  division  of  the 
larynx  by  a cord  which  is  directed  from  above  downward.(2) 

The  consecutive  deviations  of  formation, (3)  especially  those  depend- 
ent on  mechanical  injury,  are  much  more  common  than  the  primitive. 
We  must  distinguish  among  them  wounds  in  the  larynx  made  by  a 
cutting  instrument  in  suicide.  Wounds  of  the  epiglottis  are  generally 
considered  as  fatal  ; we  however  have  one  case  before  us,  where  this 
cartilage  was  entirely  divided  longitudinally,  and  also  cut  transversely 
in  its  right  half  ; but  death  did  not  ensue.  This  case  is  curious  also 
as  it  proves  what  we  stated  above,  that  the  epiglottis  is  not  absolutely 
necessary  to  close  the  glottis. 

Wounds  of  the  larynx  are  very  frequently  fatal,  from  their  conse- 
quent irritation  and  inflammation,  on  account  of  its  great  sensibility. 

Sometimes  death  occurs  at  the  end  of  a certain  time,  being  caused 
by  the  abundant  granulations  which  completely  obstruct  the  glottis, 
and  which  are  formed  in  consequence  of  a wound  which  suppurates. (4) 

The  arytenoid  cartilage  is  partially  separated  by  a cutting  instru- 
ment, and  thus  hanging  in  the  glottis,  may  cause  death  by  suffo- 
cation, like  any  other  foreign  body. (5) 

The  cartilages  of  the  larynx  are  not  necessarily  fractured  in  persons 
who  die  by  hanging,  although  they  are  sometimes  broken.(6) 

B.  ALTERATIONS  IN  TEXTURE. (7) 

§ 2290.  The  mucous  membrane  of  the  larynx  either  alone  or  with 
that  of  other  parts,  particularly  the  cavity  of  the  mouth  and  that  of 
the  trachea,  is  often  inflamed.  Sometimes  there  is  effusion,  apd  an 
accidental  membrane  is  formed,  which  more  or  less  completely  closes 
the  glottis,  and  the  patient  is  suffocated. 

In  phthisis  laryngea  also  ulcers  often  exist  which  destroy  it  in 
a greater  or  less  extent,  and  cause  abnormal  adhesions  between  it  and 
the  pharynx.  This  state  also  may  cause  suffocation  in  more  than 
one  way.  But  the  swelling  alone  of  the  inflamed  parts,  without  any 
effusion  or  ulceration,  may  be  fatal. (8) 

(1)  Atti  di  Siena,  vol.  iii.,  p.  232. 

(2)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  ii.,  pt.  ii .,  p.  140.  The 
case  cited  by  Otto  (Path,  anat.,  p.  223),  of  a larynx  divided  into  three,  does  not  refer 
to  this,  but  to  the  trachea,  which  presented  three  branches  instead  of  two  (Sandifort, 
Exerc.  ac.,  p.  65). 

(3)  G.  Beil,  Cases  of  diseases  and  wounds  of  the  larynx  ; in  his  Surgical  observa- 
tions, London,  1817,  p.  1. 

(4)  Bell,  loc.  cit.,  p.  44. 

(5)  Ibid. 

(6)  Morgagni  cites  one  case  of  rupture  of  the  cricoid  cartilage  (Ep.  anat.  med., 
vol.  xix.,  p.  13). 

(7)  Bell,  loc.  cit, — Howship,  On  the  affections  of  the  larynx  ; in  the  Practical  obser- 
vations in  surgery,  London,  1816,  p.  14. 

(8) ;  Howship,  loc.  cit.,  p.  153. 


340 


DESCRIPTIVE  ANATOMY. 


The  cartilages  of  the  larynx  are  more  subject  than  any  others  to 
ossify,  and  consequently  to  be  affected  with  all  the  diseases  peculiar 
to  the  bones. 

Among  the  new  formations  cysts  are  not  unfrequent  in  this  organ, 
although  much  less  common  than  the  preceding  anomalies.  Some- 
times they  belong  to  the  class  of  hydatids  ; there  is  more  or  less  danger 
of  suffocation  from  them  by  closing  the  glottis. 

C.  FOREIGN  BODIES. 

§ 2291.  As  substances  which  pass  into  the  stomach  from  the  upper 
part  of  the  alimentary  canal  must  necessarily  pass  over  the  epiglottis, 
foreign  bodies  not  unfrequently  enter  this  organ,  and  thence  pass  into 
the  trachea.  This  happens  particularly  when  we  talk  while  eating, 
as  then  the  glottis  is  not  closed.  These  foreign  bodies  soon  occasion 
death  by  suffocation.  A case  however  has  been  mentioned  where  a 
ducat  continued  two  years  in  the  larynx,(l)  and  another  where  a piece 
of  a nut-shell  as  large  as  a finger-nail  remained  there  seven  years. (2) 


ARTICLE  SECOND. 

ORGANS  OF  RESPIRATION. 

I.  NORMAL  STATE. 

A.  LUNGS. 

i.  PERFECT  STATE  IN  GENERAL. 

§ 2292.  The  organs  of  respiration  ( systenia  respiralorium)(3)  are 
the  lungs,  which  communicate  with  the  external  air  by  the  trachea. 
Beside  the  prolongations  of  the  trachea,  they  are  formed  by  the  pulmo- 
nary arteries  and  veins,  by  lymphatic  vessels,  nerves,  and  cellular  tis- 
sue between  these  two  parts,  and  a serous  envelop,  the  pleura. 

(9)  Hoechstetter,  Obs.  mcd.,  dec.  vi.,  c.  x. 

(1)  Tulp,  Obs.  -tried.,  1.  ii.,  c.  vii. 

(1)  RI.  Malpighi,  De  pulmonibus  epistol.  I.  et  II.  ad  A.  Borellum,  Bologna,  1661. 
— Th.  Bartholin,  De  pulmonum  substantiel  et  motu  distribe.  Ace.  M.  Malpigkii  de 
pulm.  obs.  anat.,  Leyden,  1672. — Helvétius,  Observations  sur  le  poumon  de  L’homme  ; 
in  the  Alim,  de  Paris , 1718. — Wildrik,  De  f abrita  pulmonum,  Franekcr,  1761. — 
Wohlfahrt,  De  bronchiis  vasisque  bronchialibus,  Halle,  174.8. — Hildebrandt,  De  pul- 
monibus, Gottingen,  1786. — Reisseissen,  De  pulmonum,  structura,  Strasburg-, -1803. 
— Scemmerring’  and  Rcisseissen,  lieber  die  idtruclur  die  Verrichtung  und  den  Ge- 
brauch der  Lungen,  Berlin,  1808. 


OP  THE  RESPIRATORY  SYSTEM. 


341 


A.  FORM. 

§ 2294.  The  lungs  ( pulmones ) have  the  form  of  an  irregular  cone,  the 
base  of  which  looks  downward  and  the  summit  upward.  Their  concave 
base  rests  on  the  diaphragm  ; their  very  convex  external  face  is  turned 
towards  the  ribs  ; the  internal,  which  looks  toward  the  heart,  is  corn 
cave. 

The  anterior  edge  is  blunt,  the  posterior  is  sharp. 

Each  lung  is  divided  into  two  triangular  lobes,  an  upper,  smaller,  a 
lower,  larger,  by  a deep  groove  which  extends  obliquely  from  above 
downward  and  from  behind  forward,  and  which  passes  entirely  through 
it.  Between  these  two  lobes  the  right  lung  also  presents  a third, 
much  smaller,  which  is  situated  forward,  and  contracts  much  from  before 
backward.  The  left  lung  differs  from  that  of  the  right  side,  as  its 
lower  edge  presents  a groove  in  which  the  lower  part  of  the  heart  is 
situated. 

Beside  this  difference  in  the  form,  the  right  lung  is  a little  larger  and 
lower  but  broader  than  the  left,  and  this  in  return  is  a little  more  elon- 
gated. 

Considered  as  a whole,  the  lung  is  divided  into  three,  five,  or  six 
lobes,  irregular  in  form  and  volume,  in  the  spaces  of  which  proceed 
the  blood-vessels  and  the  lymphatics,  but  the  surface  of  which  is  not 
uneven,  or  but  slightly  so. 

§ 2295.  The  posterior  edge  of  each  lung  is  cleft  in  most  of  its 
length,  and  thus  presents  a depression,  the  upper  half  of  which  re- 
ceives the  bronchiæ,  the  blood-vessels,  and  the  nerves,  while  the  liga- 
ments of  the  organ  are  attached  to  the  inferior. 

The  pulmonary  artery  is  situated  first  entirely  on  the  summit 
before  the  bronchia,  and  sends  in  this  place  a considerable  branch 
to  the  lung  ; but  it  is  soon  directed  backward,  and  passes  behind  the 
bronchia. 

The  pulmonary  veins  are  found  entirely  forward  and  downward, 
excepting  the  smallest  and  lowest  branches,  which  proceed  behind  the 
lowest  ramifications  of  the  bronchiæ. 

B.  SITUATION  AND  ATTACHMENTS. 

§ 2296.  The  lungs  are  situated  on  the  two  sides  of  the  heart.  Each 
is  inclosed  in  a special  serous  sac  termed  the  pleura,  with  the  parietes 
of  which  they  are  in  perfect  contact  in  every  part,  but  do  not  adhere, 
except  at  the  part  where  this  membrane  is  reflected  to  cover  their  ex- 
ternal face. 

Their  upper  extremity  passes  a little  beyond  the  first  rib. 


VOL.  III. 


44 


842 


DESCRIPTIVE  ANATOMY. 


C.  COLOR. 

The  color  of  the  lungs  when  a person  is  in  good  health,  is  grayish 
red,  more  or  less  spotted  with  black. 

D.  TEXTURE. 

§ 2297.  Among  the  different  parts  mentioned  as  composing  the 
lung,  the  trachea  is  the  base  of  the  others,  and  also  the  most  impor- 
tant, as  the  air  passes  through  it  to  enter  and  emerge  from  the  lung. 

a.  Trachea. 

§ 2298.  The  trachea  ( tracheia  ct  arteria  aspera ) is  a canal  about 
four  inches  long  and  nine  lines  broad,  which  begins  at  the  fifth  cervi- 
cal vertebra,  below  the  larynx,  and  is  covered  only  by  some  muscles, 
particularly  the  sterno-hyoideus  and  the  sterno-thyroideus.  It  is  situ- 
ated exactly  on  the  median  line,  passes  directly  before  the  esophagus, 
and  descends  directly  into  the  chest,  between  the  large  vessels  of  the 
head.  Thence  it  gradually  inclines  toward  the  right  side,  so  that  its 
left  portion  corresponds  to  the  centre  of  the  vertebral  column,  and  di- 
vides at  an  obtuse  angle  behind  the  arch  of  the  aorta,  about  opposite  the 
third  dorsal  vertebra,  into  two  lateral  branches,  termed  bronchi  or  bron- 
chiez. The  right  bronchia  is  generally  eight  lines  broad,  one  inch 
long,  and  the  left  is  about  half  an  inch  broad,  and  two  long.  The  di- 
rection of  this  latter  is  more  perpendicular  than  that  of  the  other  : it  is 
situated  between  the  descending  vena  cava  and  the  azygos  vein.  The 
left  turns  below  the  arch  of  the  aorta,  and  goes  forward. 

Each  bronchia  is  covered  with  the  pleura,  proceeds  obliquely  from 
above  downward,  and  from  without  inward,  toward  its  corresponding 
lung,  and  on  arriving  there,  divides  into  a superior  and  an  inferior  bron- 
chia, each  of  which  proceeds  to  a lobe.  The  lower  branch  of  the  right 
bronchia  also  soon  subdivides  into  two  twigs,  a superior,  which  is 
smaller,  and  an  inferior,  which  is  larger,  for  the  middle  and  the  in- 
ferior lobe. 

"These  canals  ramify  extensively  within  the  lung,  and  represent  a 
tree,  terminated  in  every  part  of  the  surface  of  the  organ  in  culs-de-sac, 
along  which  are  distributed  all  the  other  component  parts  of  the  lung. 
The  final  ramifications,  which  are  the  most  minute,  and  terminate  in  a 
cul-de-sae,  are  termed  the  pulmonary  cellules  ( cellulce  pulmonares). 

§ 2299.  The  trachea  is  formed  by  very  different  parts,  viz.  by 
fibrous  tissue,  cartilages,  muscular  fibres,  and  a mucous  membrane. 

a.  Fibrous  tissue. 

§ 2300.  The  fibrous  tissue  is  composed  of  longitudinal  fasciculi, 
which  do  not  form  a continuous  membrane,  but  leave  between  them  nu- 


OF  THE  RESPIRATORY  SYSTEM. 


343 


merous  oblong  spaces.  It  constitutes  the  outer  face  of  the  trachea,  and 
adheres  intimately  to  the  subjacent  mucous  membrane.  Its  vessels 
are  more  numerous  than  those  in  the  other  fibrous  organs,  and  thus  it 
resembles  the  fibrous  tunic  of  the  arteries. 

From  the  great  elasticity  of  this  tissue,  the  trachea  contracts  to  its 
former  dimensions,  after  being  distended  longitudinally. 

b.  Cartilage. 

§ 2301.  The  fibrous  tissue  of  the  trachea  and  of  its  ramifications, 
inclose  pieces  of  cartilage,  placed  successively  from  above  downward, 
on  the  two  faces  of  which  it  passes,  and  adheres  intimately.  It,  how- 
ever, does  not  cover  directly  the. surface  of  these  cartilages,  which  are 
entirely  developed  by  a special  perichondrium. 

The  form,  dimensions,  and  situation  of  these  cartilages,  vary  in  dif- 
ferent parts  of  the  trachea,  and  in  its  ramifications. 

In  the  trachea  they  form  imperfect  rings,  open  at  their  posterior  part, 
which  surround  the  anterior  and  lateral  parts  of  the  passage.  These 
rings  are  about  two  lines  high,  half  a line  thick,  and  an  inch  and  a half 
long.  They  circumscribe  about  the  two  thirds  of  the  trachea  when 
in  its  greatest  state  of  distension,  and  more  than  three  fourths  of  its 
circumference  when  it  is  collapsed. 

The  number  of  its  cartilages  varies  from  sixteen  to  twenty. 

Their  form  is  more  regular  and  more  constant  at  the  centre  of  the 
trachea  than  at  its  upper  and  lower  extremities.  In  most  of  this  canal, 
they  generally  form  rings  of  equal  extent,  and  of  about  the  same 
height. 

The  first,  on  the  contrary,  is  much  higher  than  the  others,  and  higher 
at  its  anterior  than  at  its  posterior  part.  This  arrangement  establishes 
rather  a remarkable  correspondence  from  before  backward,  between  it 
and  the  cricoid  cartilage,  in  which  there  is  an  opposite  arrangement. 

This  ring,  also,  is  most  generally  united  at  its  posterior  extremity 
with  the  second  whence  results  an  undoubted  analogy  with  the  type  of 
the  formation  of  the  larynx. 

Sometimes  there  is  a similar  adhesion  between  the  third  and  the 
fourth  ring,  either  on  both  sides,  or  more  commonly  on  one  only. 

The  lower  rings,  on  the  contrary,  frequently  present  on  one  or  both 
sides,  a greater  or  less  fissure,  that  is,  one  which  sometimes  extends  to 
their  lower  extremity,  and  sometimes  stops  short  of  it.  Frequently, 
but  not  always,  we  then  remark  on  the  opposite  side,  a small  segment 
of  an  imperfect  circle,  which  corresponds  to  one  of  the  two  halves 
formed  by  the  division,  or  a ring  cleft  on  the  other  side,  which  in  some 
measure  makes  up  for  the  want  of  symmetry.  But  we  as  commonly 
find  there  a common  and  perfect  ring,  or  one  which  is  partly  divided 
in  the  same  manner  and  on  the  same  side. 

The  rings  of  the  loose  portion  of  the  bronchiæ  are  generally  similar 
to  the  final  cartilaginous  rings  of  the  trachea. 


344 


DESCRIPTIVE  ANATOMY. 


There  are  generally  but  eight  in  the  right  bronchia,  while  there  are 
eleven  or  twelve  in  the  left.  As  they  approach  the  lungs,  they  be- 
come more  irregular,  and  are  divided  or  blended  with  the  rings  ad- 
jacent. 

The  number  of  the  cartilages  suddenly  diminishes  very  much  within 
the  lungs,  so  that  the  ramifications  of  the  bronchiæ  become  more  mem- 
branous there.  But,  at  the  same  time,  these  cartilages  lose  their  re- 
gular form  : they  cease  to  represent  rings,  and  resemble  layers  which 
are  irregularly  quadrilateral,  triangular,  &c.  Besides,  we  find  them 
in  all  parts  of  the  trachea. 

They  become  smaller  and  rarer,  in  proportion  to  the  gradual  con- 
traction of  the  ramifications  of  the  bronchiæ.  The  last  which  are  per- 
ceptible have  a rounded  form. 

We  find  none  in  those  ramifications  about  one  third  of  a line  in 
diameter,  or  at  least  they  are  extremely  small,  and  scarcely  percep- 
tible. 

Finally,  the  last  ramifications  of  the  bronchiæ  are  simply  membra- 
nous, and  some  lines  below  the  surface  of  the  lung,  we  find  no  trace  of 
cartilage, 

c.  Muscular  fibres. 

§ 2302.  The  posterior  part  of  the  trachea  is  formed  by  a muscular 
membrane, (1)  which  is  about  half  a line  thick  when  it  is  contracted. 
This  membrane  is  composed  only  of  transverse  fibres,  which  are  at- 
tached to  the  cartilaginous  rings,  and  to  the  fibrous  tissue  between 
them,  so  as  to  cover  the  inner  face  of  these  rings,  and  of  this  tissue 
about  from  one  to  two  lines. 

Within  the  lung,  where  the  cartilages  are  arranged  irregularly,  and 
distributed  on  the  whole  extent  of  the  bronchial  tree,  these  muscular 
fibres  surround  also  the  whole  trachea.  They  increase  inversely  as 
the  cartilages,  and  they  can  be  traced  farther  than  these  latter. 

d.  Mucous  membrane. 

§ 2303.  The  fibrous  tissue  and  the  muscular  tissue  of  the  trachea 
are  covered  in  their  whole  extent  by  a thin  mucous  membrane,  which 
forms  a continuous  sac,  and  adheres  intimately  to  the  adjacent  parts. 

Its  posterior  face  presents  in  the  whole  extent  of  the  trachea,  muci- 
parous glands,  arranged  compactly,  which  are  more  numerous  and 
larger  at  the  lower  part  of  the  trachea,  where  it  bifurcates,  and  in  the 
portion  of  the  bronchiæ  and  of  the  lungs.  They  are  very  near  in  these 
different  parts,  and  they  are  frequently  as  large  as  a bean. 

They  form  a continuous  layer,  situated  mostly  behind  the  muscular 
membrane,  between  the  fibres  of  which  their  very  short  excretory  pas- 

(1)  Eberhard,  DLss.  de  musculis  bronchialibus  corumque  in  statu  sano  vel  morboso 
actione , Marburg,  1817. 


OF  THE  RESPIRATORY  SYSTEM. 


345 

sages  penetrate.  This  layer  extends  uniformly  on  the  portion  of  the 
trachea  formed  by  muscular  fibres,  while  the  glands  are  principally 
collected  between  the  cartilaginous  rings,  so  that  after  removing 
these  latter,  we  easily  perceive  the  place  they  occupy  by  the  spaces  in 
the  glandular  layer. 

We  must  distinguish  from  these  muciparous  glands,  the  bronchial 
lymphatic  glands  ( G . bronchiales),  which  are  found  in  the  same 
places. 

§ 2304.  The  mucous  membrane  is  the  last  part  visible  among  those 
which  contribute  to  form  the  trachea  and  its  ramifications,  although 
reason  and  observation  unite  to  demonstrate  that  its  irritability  extends 
beyond  the  points  where  its  muscular  texture  disappears. 

The  most  minute  ramifications  of  the  trachea,  which  are  formed  by 
a homogeneous  substance,  terminate  in  a cul-de-sac,  and  are  not  con- 
tinuous, as  Helvetius  asserts,  with  the  cellular  tissue  which  unites  the 
different  organic  parts  of  the  lung.  The  trachea  forms  a hollow  tree, 
the  twigs  of  which  communicate  by  the  branches,  and  the  lattemLof 
the  trunks  resulting  from  their  union,  but  not  by  means  of  mucous  iija 
sue  existing  between  these  ramifications.  This  fact  is  established  by 
numerous  dissections  and  experiments. 

The  minutest  twigs  of  the  bronchial  tree,  when  filled  with  air  or  any 
other  fluid,  present  the  same  form  and  the  same  limits,  either  when  ex- 
amined with  the  naked  eye,  or  with  a microscope.  If  we  fill  a bron- 
chia with  air  or  any  other  fluid,  so  as  to  inject,  for  instance,  a whole 
lobe,  and  one  of  the  secondary  twigs  is  afterwards  tied,  the  part  of  the 
lung  in  which  this  latter  is  distributed  remains  swelled  and  distended, 
while  that  where  the  bronchial  twig  is  not  tied  soon  collapses. 

b.  Blood-vessels  of  the  lung's. 

§ 2305.  The  blood-vessels  of  the  lungs  are  of  two  kinds.  Most  of 
the  organ  is  formed  by  the  pulmonary  arteries  and  veins,  the  first  of 
which  carry  venous  blood,  while  the  veins  carry  back  to  the  left  half 
of  the  heart  this  fluid,  which  has  been  changed  by  the  action  of  the  air 
into  arterial  blood,  in  the  limit  between  the  two  systems. 

The  trunks  of  these  vessels  enter  and  emerge  from  the  lungs  at  the 
same  point. 

Even  within  the  organ  the  pulmonary  veins  are  nearer  the  bronchiæ 
than  the  arteries  are. 

§ 2306.  The  second  order  of  blood-vessels  includes  the  bronchial 
arteries  and  veins  ( vasa  bronchialia),  which  are  connected  with  the 
nutrition  of  the  lungs.  We  have  already  mentioned  their  origin.  These 
vessels  are  distributed  in  the  substance  of  the  lung,  along  the  ramifica- 
tions of  the  bronchiæ,  rest  on  their  surfaces,  and  surround  them  with 
numerous  plexuses.  After  supplying  the  muscular  and  the  fibrous  tis- 
sue, they  penetrate  to  the  mucous  membrane,  into  which  they  send 
numerous  ramuscules  to  the  membranes  of  the  pulmonary  vessels,  to 


346 


DESCRIPTIVE  ANATOMY. 


the  nerves  of  the  lungs,  and  form  a very  minute  and  complex  tissue  on 
the  surface  of  all  these  parts,  below  the  pleura. 

It  is  very  curious  that  the  anastomoses  occur,  not  only  in  this  vas- 
cular net-work,  but  also  between  the  considerable  branches  and  twigs 
of  the  pulmonary  and  bronchial  vessels. 

The  bronchial  veins  even  mostly  empty  into  the  pulmonary.  Those 
of  the  roots  of  the  lungs  alone  White  in  small  trunks,  which  empty  into 
the  azygos  vein,  or  the  descending  vena-cava,  or  into  the  subordinate 
twigs  of  the  system  of  the  veins  of  the  body. 

It  follows  then,  from  this  arrangement  : 

1st.  That  even  in  the  normal  state  the  vascular  systems  of  black 
and  red  blood  communicate  extensively  in  the  substance  of  the  lung. 

2d.  That  analogous  communications  which  appear  in  other  parts  as 
abnormal,  as  the  termination  of  the  coronary  veins  of  the  heart  in  the 
left  ventricle,  the  insertion  of  one  or  more  pulmonary  veins  into  the 
ticna-cava,  the  origin  of  a great  pulmonary  artery  from  the  descending 
aofhi,  &c.,  are  only  a more  marked  development  of  this  type. 

3d.  That  in  the  cases  where  the  pulmonary  artery  was  obliterated 
or  very  narrow,  and  the  subjects  lived  a long  time,  these  anastomoses 
were  probably  large  enough  to  carry  the  blood  in  the  pulmonary  ar- 
teries. In  fact,  the  bronchial  vessels  were  found  very  much  dilated  in 
a case  of  this  kind.(l) 

c.  Lymphatic  glands  and  vessels. 

§ 2307.  We  have  already  made  known  the  most  important  facts  in 
regard  to  the  distribution  of  the  lymphatic  vessels  in  the  substance  of  the 
lung,  and  of  the  lymphatic  glands  which  exist  along  the  ramifications 
of  the  trachea. 


d.  Nerves. 

§ 2308.  The  nerves  of  the  lungs  arise  from  the  pneumogastric 
nerve.  They  are  very  small  in  proportion,  but  very  numerous,  and 
they  can  be  traced  far  on  the  ramifications  of  the  bronchiæ.  They  are 
divided  into  two  orders.  Some  are  distributed  in  the  bronchial  tree, 
others  in  the  pulmonary  vessels.  The  first  penetrate  to  the  muscular 
and  mucous  membranes,  the  second  surround  the  vessels  and  pene- 
trate either  into  the  substance  of  the  great  trunks,  or  into  the  capillaries. 
Some  extend  even  to  the  pleura. 

e.  Pleura. 

§ 2309.  The  pleura  is  a serous  membrane,  the  outer  portion  of 
which,  termed  the  costal  pleura  ( pleura  coslalis),  covers  the  inner  face 

(1)  Jacobson,  in  the  Deutsches  Archiv  für  die  Physiologie , vol.  ii.p,  134, 


OP  THE  RESPIRATORY  SYSTEM.  34Î 

of  the  pectoral  cavity,  while  the  internal  or  reflected  layer,  termed  the 
pulmonary  pleura  (pleura  pulmonalis),  covers  the  external  face  of  the 
lung. 

It  adheres  to  the  parietes  of  the  chest  less  than  to  the  surface  of  the 
lung  : it  however  can  be  easily  detached  from  this  latter  organ. 

It  is  composed  of  a right  and  a left  sac  ( sacci  pleurœ ),  which  are 
separate  and  entirely  distinct. 

The  internal  parietes  of  the  external  sac  are  not  attached  to  the 
parietes  of  the  pectoral  cavity,  but  are  turned  towards  each  other,  and 
form  a septum  which  is  directed  from  above  downward,  and  from  before 
backward,  which  divides  the  chest  into  a right  and  a left  half. 

These  two  internal  parietes,  however,  do  not  touch.  They  are  sepa- 
rated in  the  centre,  and  in  most  of  the  septum  they  form,  by  the  heart  : 
backward,  by  the  aorta,  the  esophagus,  the  azygos  vein,  and  the  tho- 
racic canal  ; forward  by  the  thymus  gland  and  the  great  vascular 
trunks.  They  are  united  in  all  these  parts  by  very  loose  cellular  tissue  ; 
and  are  most  remote  from  each  other  in  their  centre.  That  portion  of 
the  septum  situated  before  and  behind  the  heart,  is  termed  the  anterior 
and  posterior  mediastinum  ( mediastinum  anterius  et  posterius). 

The  anterior  mediastinum  descends  between  the  heart  and  the 
middle  anterior  part  of  the  thoracic  cavity.  Its  direction  is  not  perpen- 
dicular, but  oblique  from  left  to  right.  Besides,  it  does  not  correspond 
perfectly  to  the  median  line,  but  is  thrown  a little  to  the  left,  for  the  an- 
terior edge  of  the  right  layer  is  attached  to  the  left  edge  of  the  sternum, 
and  that  of  the  left  layer  to  the  cartilage  of  the  left  ribs  ; thence  the 
mediastinum  descends  on  the  anterior  face  of  the  pericardium. 

The  posterior  mediastinum  is  more  perpendicular  than  the  anterior, 
and  is  situated  between  ’the  anterior  face  of  the  vertebral  column  and 
the  base  of  the  heart. 

The  external  layer  of  the  pleura  of  each  side,  is  reflected  on  itself, 
between  the  two  mediastina,  to  pass  on  the  lower  and  upper  faces  of 
the  lungs.  For  this  purpose,  it  contracts  around  the  pulmonary  vessels 
and  the  bronchiæ,  and  descends  from  the  centre  of  the  posterior  edge 
towards  the  lung.  Upward,  forward,  and  backward,  it  contracts  sud- 
denly, and  from  all  parts  towards  this  point  ; but  we  observe  below,  on 
each  side,  a considerable  triangular  prolongation,  terminated  by  a lower 
semicircular  edge,  which  begins  at  the  diaphragm,  and  is  attached  to 
the  posterior  edge  of  the  lower  lobe  of  the  lung.  This  prolongation  is 
termed  the  right  and  left  ligament  of  the  lung  ( l . pulmonis  dextrum  et 
sinistrum).  That  of  the  left  side  is  much  larger  than  that  of  the  right. 

The  pulmonary  pleura  covers  the  whole  surface  of  the  lung,  even 
its  lobes,  but  does  not  penetrate  between  these  lobes,  which  are  sepa- 
rated from  each  other  only  by  cellular  tissue. 


348 


DESCRIPTIVE  ANATOMY. 


f.  Weight  of  the  lung. 

a.  Absolute  weight. 

§ 2310.  The  sound  lung  of  an  adult  male,  with  all  the  blood  and 
the  air  it  contains,  weighs  about  four  pounds.  When  removed  from 
the  body,  the  pressure  of  the  external  air,  which  had  been  prevented 
from  acting  on  it,  expels  a considerable  portion  of  this  fluid  which  re- 
mained in  it  after  the  last  expiration. 

Its  weight  then  is  to  that  of  the  whole  body  about  as  1 : 35. 

b.  Specific  gravity. 

§ 2311.  Considered  in  itself,  the  substance  of  the  lung  is  heavier 
than  water,  for  the  lungs  of  a child  which  has  never  breathed  sink  in 
this  fluid.  But  when  respiration  has  commenced  the  specific  weight 
of  the  organ  is  less  than  that  of  water,  as  the  air  which  enters  there  is 
not  entirely  expelled  during  expiration.  We  cannot  even  press  it  out 
from  a section  of  the  lung  : for  then,  after  rupturing  the  ramifications 
of  the  bronchiæ,  it  extends  in  the  cellular  tissue,  so  that  at  the  end 
of  the  experiment  the  substance  of  the  lung  is  still  lighter  than  the 
water,  although  a little  heavier  than  it  was  before.(l) 

g.  Capacity. 

§ 2312.  The  capacity  of  the  lung  is  not  the  same  in  all  periods  of 
life.  It  varies  much,  according  as  the  organ  is  distended  at  the  end 
of  inspiration  ( inspiratio ),  or  in  that  of  contraction,  at  the  end  of  expi- 
ration ( expiratio ). 

The  estimates  given  by  authors  vary,  which  may  arise  from  a real 
difference  in  the  capacity  of  the  lung  and  the  nature  of  the  modes 
employed  to  estimate  it. 

In  the  first  respect  there  are  very  great  individual  differences,  which 
are  mostly  congenital,  but  which  may  be  accidental,  as  when  the  lungs 
are  but  slightly  used,  for  instance,  in  students. 

The  capacity  of  the  lung  is  determined  by  adding  the  quantity  of 
air  expelled  during  expiration  with  that  which  remains  there  after 
this  act  is  completed.  This  calculation  may  be  made  in  several  dif- 
ferent ways. 

Three  processes  can  be  used  to  determine  the  quantity  of  air  which 
enters  the  lung  at  each  inspiration  : 

1st.  We  may  measure  the  enlargement  of  the  lung  in  inspiration, 
and  the  contraction  after  expiration. 

(1)  Allen  and  Pepys,  Second  pager  on  respiration  ; in  the  Phil,  trans.,  1809,  p.  4L 


OF  THE  RESPIRATORY  SYSTEM. 


349 


2d.  We  estimate  the  changes  which  supervene  during  inspiration 
and  expiration  in  a fluid  in  which  the  individual  is  situated. 

3d.  We  measure  the  quantity  of  the  air  inspired  and  expired,  by 
inspiring  from  a vase  which  has  been  measured,  and  expiring  into 
another,  the  capacity  of  which  is  also  known,  or  by  the  last  proof 
alone.(l) 

At  present  the  estimates  of  the  quantity  inhaled  and  expelled  at 
each  respiration  varies  much,  from  three  to  forty  cubic  inches.  In 
fact,  Abildgaard  estimates  it  at  three  inches  ;(2)  Wurzer(3)  and  La- 
metherie,(4)  at  eight  or  ten  ; Keutsch,(5)  between  six  and  twelve  ; 
Abernetby,(6)  Lavoisier,  Seguin, (7)  and  Davy, (8)  at  thirteen  ; Bo- 
relli(9)  and  Goodwyn,(10)  at  fourteen;  Kite, (11)  Allen,  and  Pe- 
pys,(12)  at  seventeen  or  eighteen  ; Herholdt,(13)  between  twenty-five 
and  twenty-nine  ; Cavallo,(14)  Jurin,(15)  Sauvages, (16)  Hales, (17) 
Hal'er,(18)  Chaptal,(19)  Bell,(20)  Fontana, (21)  Menzies,(22)  and 
Richerand,(23)  between  thirty  and  forty  cubic  inches. 

In  estimating  the  quantity  of  air  remaining  in  the  lung  after  expira- 
tion, the  following  circumstances  are  attended  to  : 

1st.  After  expiration,  as  long  as  the  chest  remains  closed  and  the 
lungs  are  not  removed,  these  organs  contain  more  air  than  when  sepa- 
rated from  the  body,  because  they  collapse  after  opening  the  chest,  and 
thus  expel  the  air  they  contain. 

2d.  It  is  very  difficult  to  expel  the  air  which  remains  in  the  lung, 
and  it  can  never  be  completely  removed  by  the  greatest  possible 
pressure.. 

(1)  Jurin,  in  Haller,  El.  phys .,  1.  viii.,  s.  iii. 

(2)  Neue  Versuche  über  das  Athmen  und  den  Nutzen  desselben  ; in  the  Nordisches 
Archiv,  für  Natur -und  Arzneywissenchaft , vol.  i.,  pt.  i.,  p.  2. — Abildgaard  however 
asserts  in  another  place  (ibid.,  pt.  ii.,  p.  206),  that  from  two  to  seven,  and  sometimes 
even  fifteen  cubic  inches  enter. 

(3)  Gunther,  Darstellung , p.  28. 

(4)  Journ.  de  physique,  vol.  xlvi.,  p.  108. 

(5)  De  act.  gaz  cxygenii  per  pulm.  resp.,  Copenhagen,  1800. 

(6)  Essays,  London,  1793,  vol  ii.,  p.  144. 

(7)  Mémoire  sur  la  respiration,  &c. 

(8)  Researches  concerning  nitrous  oxyd , London,  1800,  p.  433. 

(9)  De  motu  animalium,  p.  ii.,  prop.  81. 

(10)  Recherches  expérimentales  sur  les  effets  que  produisent  sur  les  animaux  vivons 
la  submersion,  la  strangulation,  &c.,  Paris,  1798. 

(11)  lieber  Wiederherstellung  scheinbar  todter  Menschen , p.  19. 

(12)  Loc.  cit. 

(13)  Nordischés  Archiv.,  vol.  i.,  pt.  ii.,  p,  207. 

(14)  lieber  Anwendung  der  Gasarten. 

(15)  Dies.  phys.  math.,  London,  1732,  diss.  iv.  ; in  Haller,  De  part,  corp.  hum.  fab., 
vol.  vi.,  p.  325. 

(16)  In  Haller,  El.  phys.,  vol.  iii.,  p.  234. 

(17)  Statical  essays,  vol.  i.,  p.  238. 

(18)  El.  phys.,  vol.  iii.,  loc.  cit. 

(19)  Chemie;  in  Bostock,  Heber  das  Athmen,  p.  189. 

(20)  Anatomy,  vol.  ii.,  p.  193. 

(21)  Phil.  Irans.,  1799,  p.  349. 

(22)  De  respiratione,  Edinburgh,  1790. 

(23)  Physiologie,  vol.  i.,  p.  374. 

Vol.  III.  45 


350 


DESCRIPTIVE  ANATOMY 


Several  methods  have  been  proposed  to  estimate  the  quantity  of  air 
which  remains  in  the  lungs  after  expiration. 

1st.  After  fixing  the  diaphragm  as  firmly  as  possible,  the  abdomen 
is  tied  and  the  lungs  collapsed,  by  making  an  incision  in  the  parietes 
of  the  chest,  we  fill  the  space  between  these  paiietes  and  the  organ 
with  water,  which  it  is  asserted  should  be  equal  in  quantity  to  that 
of  the  air  expelled  from  the  lung  by  the  pressure  of  the  liquid,  and 
also  that  of  the  external  air  introduced  into  the  chest  through  the 
parietes. 

2d.  On  opening  the  lung  the  air  is  received  from  it  in  a bladder 
adapted  to  the  trachea,  and  it  is  measured  ;(1)  the  lung  is  then  im- 
mersed in  water,  the  specific  gravity  of  which  is  about  equal  to  that 
of  distilled  water,  while  its  absolute  wmight  is  known  : the  quantity 
displaced  is  weighed,  and  w'e  determine  the  cubic  quantity  of  air  it 
still  includes. 

From  these  two  methods  we  may  conclude  the  quantity  of  air  re- 
maining in  the  lung  of  an  adult  after  a con  plete  expiration  to  be  about 
one  hundred  and  ten  cubic  inches.  In  fact,  Gcodwyn  has  introduced 
from  ninety  to  one  hundred  and  twenty  cubic  inches  of  water  in  the 
space  between  the  chest  and  the  lung. 

In  Allen  and  Pepys’  experiments,  the  quantity  of  air  first  collected 
was  31.580  cubic  inches:  the  lungs,  which  weighed  four  pounds, 
and  which  from  their  weight  occupied  as  much  space  as  an  equal 
quantity  of  water,  displaced  six  pounds  of  the  liquid,  so  that  there  still 
remained  within  them  a quantity  of  air  equal  to  an  ounce  of  water, 
that  is,  59.554  cubic  inches.  The  total  of  these  two  sums  gives  a 
little  more  than  ninety-one  cubic  inches,  as  the  quantity  of  air  remain- 
ing in  the  lung  after  expiration  ; but  we  may  admit  it  as  about  one 
hundred  and  ten,  on  account  of  the  pressure  of  the  water  on  the  mass 
of  the  lung,  and  the  higher  temperature  during  life. 

If  we  add  to  these  one  hundred  and  ten  cubic  inches  of  air  remaining 
in  the  lung  after  a common  expiration,  about  thirty  inches  which  leave 
the  organ  at  each  common  expiration  of  a healthy  adult, (2)  we  shall 
have  one  hundred  and  forty-five  inches  as  the  capacity  of  the  lungs 
in  common  inspiration,  so  that  the  difference  of  capacity  between 
the  state  of  dilatation  and  collapse  of  the  organ  is  about  thirty-five 
inches. 

But  this  difference  increases  very  much  when  the  respiration  being 
deeper,  the  lung  is  unusually  dilated  and  collapsed,  because  more  air 
enters  and  leaves  the  lung  at  each  time. 

(1)  Cline,  in  Allen  and  Pepys,  loc.  cit. 

(2)  We  take  this  as  the  mean  number  : it  seems  to  us  that  a lower  estimate  should 
be  ascribed  to  an  unusual  smallness  in  the  lung1 2,  or  to  careless  calculation,  and  that  a 
greater  estimate  depends  upon  an  unusual  development  of  the  chest,  or  on  a very 
(leep  respiration.  Farther,  we  ought  to  mention  that  the  air  is  dilated  one  sixth  by 
the  heat  of  the  body. 


OF  THE  RE3PIRATORV  STSTEM. 


251 


Thus  Seguin(l)  inhaled  in  a very  deep  respiration  one  hundred  and 
thirty  inches  of  air,  which  would  expand  by  the  heat  of  the  body  to 
one  hundred  and  fifty,  so  that  then  the  capacity  of  the  lung  was  equal 
to  two  hundred  and  sixty  cubic  inches.  Kite  estimates  the  capacity 
at  three  hundred  cubic  inches. 

On  the  other  hand,  Jurin  expired  two  hundred  and  twenty  cubic 
inches, (2)  and  Herholdt,  208.(3)  If  we  admit  here  that  these  expira- 
tions took  place  after  a full  inspiration,  we  ought  to  reduce  the  capa- 
city of  the  'lung  to  fifty-two  and  even  to  forty  cubic  inches,  which 
estimate  perfectly  agrees  with  that  formed  by  Davy  by  another 
method.(4) 

In  contrasting  the  estimates  of  Seguin  and  Jurin,  and  disregarding 
the  diminution  of  the  volume  of  the  air  expired,  we  find  a difference  of 
two  hundred  and  twenty  between  the  greatest  dilatation  and  the 
greatest  relaxation  of  the  lung,  that  is,  this  latter  state  is  to  the 
other  as  1 : 6.5. 

h.  Force  of  the  lung’. 

§ 2313.  The  lung  is  not  very  sensible.  Its  transverse  and  its  lon- 
gitudinal muscular  fibres,  which  are  similar  in  their  nature  to  muscles, 
give  it  the  power  of  contracting,  which,  judging  from  experiments, (5) 
is  exerted  whenever  its  external  or  internal  surface  is  stimulated,  and 
which  without  stimulation(6)  executes  the  motions  which  cannot  be  at- 
tributed to  those  of  the  parietes  of  the  thorax,  since  they  are  simultane- 
ous with  these  latter,  and  are  observed  when  the  parietes  of  the  thorax 
are  destroyed. (7)  Consequently  the  air-passages  contract  actively 
during  expiration  ;(8)  but  all  these  phenomena,  adduced  to  prove  that 
the  lungs  possess  a power  of  extension  which  allow  them  to  dilate 
actively  in  inspiration,  can  be  satisfactorily  explained  in  another 
manner.  (9) 

(1)  Observations  générales  sur  la  respiration  et  sur  la  chaleur  animale  ; in  the 
Journ.  de  physique.  1790,  p.  467. 

(2)  In  Haller,  loc.  cit.,  p.  326. 

(3)  Loc.  cit.,  p.  41. 

(4)  Loc.  cit.,  p.  409. 

(5)  Varnier,  in  the  Mém.  de  la  soc.  roy.  de.med.,  ann.  1779. 

(6)  Rudolphi,  Ueber  das  Athemholen  ; in  his  Anat.  phys.  Abhandlungen , p.  111. — 
Flormann,  ibid.,  p.  110. 

(7)  Bremond,  Expériences  sur  la  respiration  ; in  the  Mém.  de  Paris,  1739,  p.  455. 
— This  author  however  adduces  as  proofs  several  phenomena  which  are  by  no  means 
conclusive. 

(8)  J.  Carson,  Mémoire  sur  l'élasticité  des  poumons  ; in  the  Arch.  gen.  de  méd., 
vol.  ii.,  p.  134. 

(9)  J.  D.  Herholdt,  Ueber  die  chirurgische  Behandlungen  der  Brustvrunden, 
veranlasst  durch  neue  Versuche  über  den  Mechanismus  des  Athemholens  ; in  the 
Nordisches  Archiv.,  vol.  ii.,  pt.  i.,  p.  44-60. 


352 


DESCRIPTIVE  ANATOMY. 


».  Function  of  the  lung. 

§ 2314.  The  function  of  the  lung  is  respiration,  which  consists  es- 
sentially in  the  change  of  venous  into  arterial  blood  by  the  expulsion 
of  carbon  and  the  absorption  of  oxygen.  The  atmospheric  air  enters 
into  the  organ  during  inspiration,  and  emerges  from  it  loaded  with 
carbonic  acid  during  expiration  ; this  change  of  the  blood,  and  the  cold 
produced  by  the  evaporation  of  the  water  exhaled,  are  the  most  im- 
portant functions  of  the  lungs  ; but  the  variations  in  its  capacity  also 
affect  the  circulation,  for  the  blood  circulates  more  rapidly  from  the 
right  half  of  the  heart  into  the  pulmonary  artery  during  inspiration, 
and  from  the  pulmonary  veins  into  the  left  portion  of  the  heart  during 
expiration. 


II.  SEXUAL  DIFFERENCES. 

§ 2315.  The  lungs  of  the  male  are  larger  than  those  of  the  female, 
and  the  latter  are  more  oblong  than  those  of  the  male. 

III.  DIFFERENCES  DEPENDENT  ON  DEVELOPMENT. 

§ 2316.  The  lung  presents  considerable  periodical  differences^  1)  in 
respect  to  its  existence,  situation,  texture,  color,  contents,  volume,  and 
finally  its  absolute  and  relative  weight. 

1st.  Existence.  The  lung  is  one  of  the  last  organs  to  appear.  It 
begins  to  be  distinctly  seen  about  the  end  of  the  second  month  of  preg- 
nancy. 

2d.  Situation.  From  the  greater  proportional  volume  of  the  heart 
and  its  slight  development,  the  lung  is  situated  much  more  posteriorly 
before  than  after  birth,  so  that  sometimes  it  is  not  seen  at  all  on  opening 
the  cavity  of  the  thorax  ; consequently  it  covers  the  pericardium,  and 
generally  does  not.  entirely  fill  the  sac  of  the  pleura,  and  hence  does 
not  touch  the  parietes  of  the  chest. 

3d.  Texture.  At  the  third  month  of  pregnancy  we  begin  to  distin- 
guish the  cartilaginous  tissue  in  the  air-passages  of  the  lungs.  The 
lobules  are  at  first  united  by  a looser  cellular  tissue  than  that  com- 

(1)  Meckel,  Mémoire  sur  le  développement  du  cœur  et  des  poumons  dans  les  mam- 
mifères ; in  the  Journ.  compl.  dessc.  m éd.,  vol.  i.,  p.  259. — Consult  also  on  the  differ- 
ence in  the  lung-  of  the  child  before  and  after  respiration,  G.  J.  Schmitt,  \eve  Ver- 
suche und  Erfahrungen  über  die  Plocquetsche  und  hydrostatische  Lungenprobe , 
Vienna,  1806. — A.  Lccieux,  Considérations  medico-légales  sur  l'infanticide , Paris, 
1011. — Magendie,  Sur  la  structure  du  poumon  de  l'homme , sur  les  modif  cations 
qu'éprouve  celle  structure  dans  les  divers  âges , et  sur  la  première  origine  de  la 
phthisie  pulmonaire  ; in  the  Journ.  de  physiol,  expérim.,  vol.  i.,  p.  78. — Fleischmann, 
Sur  la  formation  de  la  trachée-artère  ; in  the  Journ.  compl.  du  diet,  des  sc.  méd., 
vol.  xvi.,  p.  141. — Id.,  De  chondrogenesi  asperiœ  arterice  et  de  situ  oesophagi  abnormi 
nonnulla,  Erlangen,  1820. 


OF  THE  RESPIRATORY  SYSTEM 


353 


monly  seen,  and  they  are  also  formed  of  small  subordinate  lobes,  so 
that  here,  as  in  other  parts,  as  the  muscles,  the  homogeneous  mass  is 
at  first  divided  into  its  great  subdivisions,  but  afterward  into  the 
smaller  parts. 

4th.  Color.  The  color  of  the  lung  is  at  first  reddish  white  in  the 
fetus,  and  is  whiter  the  younger  the  fetus  is.  This  organ  gradually  be- 
comes of  a deeper  red,  in  proportion  as  it  is  better  supplied  with  bleed. 
After  birth  this  tint  is  bright  from  respiration,  and  also  becomes 
deeper.  At  twenty  years  the  lung  is  gray,  mottled  with  blue  and 
black  spots,  and  from  this  time  its  color  becomes  still  darker,  so  that 
in  advanced  life  it  is  more  or  less  generally  black  or  bluish  black. 

5th.  Contents.  The  trachea  and  its  ramifications  contain  after  birth 
only  air,  and  a small  quantity  of  aqueous  vapor  and  mucus.  But  this 
is  not  true  of  the  fetus,  where  it  is  filled  with  the  fluid  of  the  amnion. 
By  the  laws  of  hydraulics,  when  the  fetus  swims  in  this  fluid  it  enters 
the  trachea,  without  any  respiratory  motion  on  the  part  of  the  fetus. 
It  usually  escapes  after  birth,  and  when  it  does  not  escape  at  this  time, 
which  is  rare,  it  may  suffocate  the  child.(l) 

6th.  Volume.  The  lung  is  at  first  much  smaller  ; it  occupies  much 
less  space  than  the  heart,  and  . is  easily  blended  with  the  very  dilated 
auricles  of  this  latter. 

It  does  not  acquire  its  normal  proportional  size  till  puberty. 

7th.  Weight.  The  absolute  weight  of  the  lung  presents  very  re- 
markable periodical  differences,  which  depend  on  the  organ  remaining 
inactive  until  after  biith.  In  the  fetus  its  specific  gravity  is  greater 
than  that  of  water,  in  which  it  sinks  ; but  when  respiration  has  once 
commenced,  as  it  is  never  free  from  the  air  which  has  entered  in  it,  its 
specific  gravity  is  less  than  that  of  the  water,  and  it  floats. 

§ 2317.  Most  of  the  differences  mentioned,  especially  those  in  regard 
to  situation,  volume,  color,  and  specific  gravity,  appear  more  or  less  at 
birth,  and  result  from  respiration. 

The  lung,  becoming  lighter  from  the  effect  of  the  air  entering-  it 
and  which  never  entirely  leaves  it,  occupies  also  more  space  after^-es- 
piration,  and  is  situated  more  anteriorly,  covers  most  of  the  pericar- 
dium, and  is  in  contact  with  the  parietes  of  the  chest.  The  deep  red 
color  communicated  to  it  by  the  venous  blood  before  respiration 
changes  to  a bright  red  when  the  new  being  breathes. 

Finally  the  organ,  which  when  collapsed  received  less  blood,  and 
was  consequently  lighter,  becomes  heavier  when  after  being  distended 
by  respiration,  it  is  more  permeable  to  the  blood. 

Hence  these  differences  have  been  thought  sufficient  to  determine 
whether  an  infant  was  born  living  or  dead.  But  as  the  specific  ora- 
vity  having  diminished,  the  lung  floats,  which  proof  constitutes  what  is 

(1)  P.  Scheel , Commentatio  de  liquoris  amnii  asperice  arteriœfœtuum  humanorvm 
natura  et  usu  ejusque  in  asphyxium  neonatorum  et  medicinam  forensem  infiuxu 
Copenhagen,  1799.— Herholdt,  in  Reil,  Arch.iv.fur  die  Physiologie , vol.  iii.,  p.  163  — 
Id.,  in  the  Nordisches  Archiv.,  vol.  i,  p.  212. 


354 


DESCRIPTIVE  ANATOMY. 


termed  the  test  hydrostatica  ;(1)  as  also  the  afflux  of  the  blood  in- 
creases the  absolute  weight  of  the  organ,  and  its  relative  weight 
compared  to  that  of  the  body  constitutes  another  kind  of  proof,  termed 
the  test  by  the  balance, (2)  this  principle  has  been  laid  down,  that 
when  the  lungs  of  a child  swim  in  water,  and  a similar  or  analogous 
proportion  exists  between  the  relative  weight  of  the  lungs  and  that  of 
the  body,  it  is  established  that  this  child  was  born  alive  and  that  it 
breathed. 

Considered  generally  and  absolutely,  these  conclusions  are  correct  ; 
but.  great  and  important  restrictions  are  necessary. 

1st.  The  lungs  may  become  lighter  by  respiration,  and  the  child 
not  be  born. 

2d.  The  lungs  may  swim  from  some  other  cause  than  respiration. 

3d.  Respiration  does  not  necessarily  produce  this  change  in  them. 

4th.  The  lungs  sometimes  have  a greater  absolute  weight,  although 
respiration  has  not  taken  place. 

5th.  On  the  other  hand,  they  may  present  after  respiration  a specific 
gravity  as  great  as  that  they  possess,  according  to  the  general  opinion, 
before  this  act. 

In  fact  : 

1st.  The  infant  sometimes  breathes  sufficiently  during  parturition 
to  render  its  lungs  capable  of  swimming,  although  it  may  be  still- 
born. (3) 

2d.  The  lungs  may  also  swim  from  the  fact  that  the  air  has  been 
pushed  into  them,  through  the  mouth  or  nose,  either  while  they  con- 
tinued in  the  thorax,  or  after  their  removal  from  this  cavity.  Putre- 
faction also  may  give  rise  to  the  same  result. 

3d.  Several  experiments  demonstrate  that  respiration  does  not  ne- 
cessarily cause  in  the  lungs  the  above  mentioned  changes.  Some 
parts  of  a lung,  or  even  an  entire  lung,  have  been  seen  which  did  not 
swim  in  water,  although  the  child  has  lived,  breathed,  and  cried,  not 
only  for  several  days, (4)  but  even  for  six  weeks.  We  have  seen  in  a 
child  six  weeks  old  all  the  middle  lobe  of  the  right  lung,  and  in  ano- 
ther four  weeks  old,  great  portions  of  the  same  lobe  apparently  healthy, 
which  were  absolutely  incapable  of  floating. 

The  left'  lung  is  most  frequently  retarded  in  its  development,  which 
peculiarity  doubtless  depends  on  the  fact  that  the  right  bronchia  is 
much  shorter  and  broader  than  the  left,  so  that  usually,  even  in  chil- 
dren who  died  soon  after  birth,  the  right  lung  floated,  while  the  left 
floated  very  imperfectly,  or  not  at  all.(5) 

(1)  F.  Alberg-,  De  docimasiâ  'pulmonum  hydrostatica , Halle,  1791. 

(2)  G.  G.  Plocquct,  Comm.  med.  in  processus  criminates  super  homicidio,  infanti- 
cidio  et  embryoctonia,  Strasburg-,  1787. 

(3)  Schmitt  (loc.  eit..  p.  150-176)  has  reported  examples  of  this. 

(4)  Kaltsclimied,  De  exp.  pulm.  infant,  aq.  injectis , ann.  1751. 

(5)  A.  Portal.  Mémoire  dans  lequel  on  démontre  l’action  du  poumon  sur  l’aorte 
pendant  le  temps  de  la  respiration,  et  où  Von  prouve  que,  dans  l’enfant  qui  vient  de 


OF  THE  RESPIRATORY  SYSTEM. 


355 


It  is  at  least  very  rare  that  the  contrary  occurs. 

a.  The  rarest  case  is  when  the  cause  of  the  sinking  of  the  lung 
depends  on  a morbid  alteration  in  its  texture,  an  effusion,  an  indura- 
tion, for  these  are  very  unfrequent  before  birth,  and  even  when  they 
occur  to  a great  extent,  the  organ  does  not  acquire  a greater  specific 
gravity  than  that  of  water. 

b.  A more  common  cause  is  the  presence  of  foreign  bodies,  espe- 
cially mucus,  and  the  fluid  of  the  amnion  in  the  trachea,  or  the  feeble- 
ness of  the  fetus,  all  which  circumstances  render  the  dilatation  of  the 
lung  imperfect. 

c.  We  must  remark  also  that  this  change  in  the  specific  gravity 
supervenes  gradually,  and  when  the  respiration  takes  place  with  the 
requisite  degree  of  strength,  as  in  the  beginning,  and  when  the  child 
respires  but  feebly,  it  extends  to  some  parts  of  the  lung  only,  and 
sometimes  it  is  not  produced  at  all  by  the  first  inspirations. 

4th.  Sometimes,  although  the  child  has  not  breathed,  the  lungs 
have  an  absolute  and  consequently  a relative  weight,  in  proportion  to 
the  body,  as  great  as  when  the  child  has  respired.  There  are  some 
cases  where  the  relation  between  the  weight  of  the  lung  and  the  body 
is  still  greater,  for  instance,  as  1 V15A,  to  29ff,  to  33f,  to  32^f,  to 
34t735t,(1)  although  respiration  did  not  take  place. 

This  circumstance  is  still  more  curious,  as  the  lungs  contained  also 
more  blood  than  usual. 

5th.  Observation  likewise  proves  that  the  lungs  of  infants  born  alive 
are  sometimes  proportionally  lighter  than  those  of  still-born  children 
are,  according  to  the  preceding  estimate, (2)  as  they  are  found  in  the 
proportion  of  1 : 77T9T,  to  77if,  and  to  104. 

II.  ABNORMAL  STATE. (3) 

§ 2318.  Primitive  deviations  of  formation.  The  lungs  present  pro- 
portionally but  few  anomalies  resulting  from  a primitive  deviation  of 
formation  ; they  however  sometimes  manifest  them  in  respect  to  quan- 
tity and  quality. 

1st.  The  congenital  anomalies  in  regard  to  quantity  are  generally  : 

a.  Deviations  of  formation  from  an  arrested  development.  Here 
are  arranged  particularly  : 

a.  The  absence  of  the  trachea,  of  a lung,  or  of  the  two  lungs;  this 
last  anomaly  usually  attends  acephalia  vera  ; the  second  is  more  rare, 


naître,  le  poumon  droit  respire  avant  le  gauche  ; in  the  Mém.  de  Paris,  1765. — Some 
writers  have  attributed  this  discovery  to  Petit,  but  wrongly  : he  mentions  only 
one  case  (Mém.  de  Paris,  1753),  and  does  not  point  out  the  real  cause  of  the  pheno- 
menon. 

(1)  Schmitt,  loc.  cit.,  p.  139. 

(2)  Id.,  ibid. 

(3)  Van  den  Bosch,  Commentatio  exhibons  analomiam  systematic  respirations  in - 
servientis  pathologicam,  Harlem,  1801. 


356 


DESCRIPTIVE  ANATOMY. 


and  also  occurs  in  subjects  whose  formation  is  otherwise  normal,  and 
resembles  the  normal  singleness  of  the  lung  in  several  serpents.  The 
absence  of  the  trachea  is  less  common  than  that  of  the  lungs  ; when 
it  occurs  the  lung  is  situated  next  to  the  larynx,  as  also  in  several 
reptiles. 

b.  Narrowness  and  closing  of  the  trachea,  which  has  been  observed 
when  the  skull  was  deficient.(l) 

c.  The  smallness  of  one  or  of  the  two  lungs.  The  first  anomaly  is 
generally  produced  mechanically  by  an  external  obstacle,  particularly 
the  presence  of  the  abdominal  viscera  in  the  cavity  of  the  thorax  in  a 
subject  affected  with  diaphragmatic  hernia.  The  second,  which  is 
generally  connected  with  narrowness  of  the  thoracic  cavity,  depends 
on  a primitive  dynamic  anomaly  of  the  formative  power,  and  some- 
times occurs  in  individuals  otherwise  well  formed,  and  sometimes  is 
attended  with  other  deviations  in  formation,  arising  from  suspended 
development. 

d.  We  ought  also  to  mention  here  the  exposure  of  the  lungs  or 
trachea  sometimes  observed,  since  it  depends  upon  the  formation  of  the 
parietes  of  the  thorax  being  arrested  at  one  of  the  early  periods 
through  which  it  successively  passes. 

b.  The  great  size  of  a lung,  attended  generally  by  the  deficiency  of 
the  other,  results  from  an  excessive  action  in  the  formative  power. 

2d.  Congenital  deviations  in  form  relative  to  the  quality  are  : 

a.  The  abnormal  division,  which  is  indicated  in  the  lungs  by  the 
presence  of  an  unusual  number  of  lobes,  or  by  the  deeper  separation  of 
those  always  existing,  and  in  the  trachea  by  its  division  into  three 
branches.  This  last  anomaly,  judging  from  facts  hitherto  collected, 
occurs  only  on  the  right  side,  and  is  curious  as  a repetition  of  the  pecu- 
liar structure  of  the  ruminantia  and  the  cetaceous  animals. 

b.  An  opposite  anomaly  occurs  when  the  lungs  are  not  divided  into 
lobes  as  usual,  or  when  this  division  is  not  clearty  indicated. 

c.  Lateral  inversion  is  where  the  right  lung  has  but  two  lobes  and 
the  left  three.  This  anomaly  commonly  occurs  only  when  there  is  a 
genera!  lateral  inversion. 

Consecutive  deviations  of  formation.  The  pure  consecutive  accidental 
deviations  of  formation  are  particularly  wounds,  which  often  suddenly 
cause  death,  on  account  of  the  considerable  caliber  of  the  vessels,  but 
sometimes  death  occurs  from  the  dangerous  inflammation  and  suppu- 
ration of  such  important  organs  ; but  they  are  not  necessarily  nor 
always  fatal. 

We  must  mention  here  the  abnormal  communication  with  the  other 
cavities,  which  sometimes  occurs  when  the  parietes  are  destroyed  ; 
the  most  remarkable  is  that  which  occurs  in  aneurism  of  the  aorta. (2) 

(1)  Otto,  Monst.  sex.  disq.,  p.  10,  11. 

(2)  Richerand,  Observations  sur  l'ouverture  des  anévrysmes  de  l'aorte  dans  la 
trachée-artère  et  dans  les  bronches;  in  the  Mém.  de  la  soc.  méd.  d'emul.,  vol.  iv  , 
p.  645. 


OF  TIFE  RESPIRATORY  SYSTEM. 


357 


In  this  case,  from  the  respective  situation  of  the  parts,  the  opening 
usually  corresponds  to  the  lower  part  of  the  trachea,  or  to  the  left 
bronchia. 

§ 2319.  Alterations  in  texture.  They  are  : 

1st.  Inflammation,  generally  termed  pneumonia , bronchitis , and 
pleuritis , according  as  the  whole  substance  of  the  lung,  the  mucous 
membrane  of  the  trachea,  or  the  pleura,  is  affected.(l) 

The  most  usual  consequences  of  pneumonia  are  : 
a.  Thickening  and  induration  of  the  tissue  of  the  lungs,  from  an 
effusion  often  existing  in  a great  degree,  and  then  forming  the  state 
termed  hepatization  ( hepatisatio)(2 ) The  substance  of  the  lung  is 
then  generally  homogeneous,  friable,  brittle,  grayish  white,  much 
thicker  in  texture,  and  sometimes  - possesses  a specific  gravity  greater 
than  that  of  water. 

2d.  Suppuration  Pus  usually  burrows  for  itself  a passage  into  the 
bronchiæ.  More  rarely  it  is  effused  into  the  chest,  constituting  empyema, 
or  into  the  adjacent  organs,  as  the  pharynx  or  the  aorta.(3) 

Bronchitis  terminates  sometimes  by  suppuration,  sometimes  by  the 
formation  of  solid  or  hollow  membranes,  which  fill  this  cavity  and  rarely 
adhere  to  its  inner  face.  Very  probably,  however,  the  development  of 
these  accidental  membranes  is  not  always  and  necessarily  preceded 
by  an  inflammation  of  the  trachea. (4) 

The  consequences  of  pleuritis  are  : 

(1)  C.  Hastings,  A treatise  on  inflammation  of  the  mucous  membrane  of  the  lungs, 
London,  1820. — T.  Alcock,  Observations  on  the  inflammation  of  the  mucous  mem- 
brane of  the  orga  ns  of  respiration,  London,  1820. 

(2)  Bricheteau,  De  l’ hépatisation  pulmonaire  ; in  the  Journ.  compl.  des  sc.  mid., 
vol.  ix.,  p.  106. 

(3)  V.  Laennec,  De  V auscultation  médiate,  vol.  i. — Andral,  Clinique  médicale,  vol. 
ii. — Louis,  Observations  relatives  à la  perforation  du  parenchyme  du  poumon  ; in  the 
Archiv,  gén.  de  mcd.,  vol.  v.j  p.  321. — Bouillaud,  Nouvelles  observations  sur  la  gan- 
grène des  poumons  ; in  the  Revue  médicale,  vol.  iv.,  p.  375. 

(4)  This  proposition  cannot  be  admitted.  It  rests  upon  a fact  mentioned  first  by 

Bayle,  and  since  enlarged  upon  by  Andral,  that  sometimes  in  individuals  af- 
fected with  chronic  bronchitis,  even  with  an  expectoration  of  pus,  the  mucous  mem- 
brane is.  hardly  rosy  or  even  perfectly  white  in  its  whole  extent.  But  ought  not  we 
then  to  admit  that  the  tissue  is  discolored  after  death  1 Farther,  it  is  remarkable 
that  the  softening  and  ulcerations  are  much  more  rare  in  the  mucous  membrane  of 
the  bronchiæ  than  in  that  of  the  intestine,  and  that  the  frequency  of  the  ulcerations 
decreases  from  above  downward.  The  inflammation  of  this  membrane  frequently 
terminates  also  in  thickening,  which  causes  the  contraction  of  the  bronchiæ.  Hy- 
pertrophy even  sometimes  extends  more  or  less  to  the  external  fibrous  and  cartila- 
ginous tissues.  We  must  not  confound  the  contraction  of  the  bronchiæ,  which  re- 
sults from  it,  with  that  which  comes  from  the  compression  of  these  canals  by  a 
tumor,  among  others  by  tumefied  ganglions,  which  are  rather  common  in  children, 
or  by  au  aneurism  of  the  aorta.  Chronic  inflammation  results  also  in  a dilatation  of 
the  bronchiæ,  to  which  Laennec  first  attracted  attention,  and  which  has-been  studied 
very  carefully  since  by  Andral,  as  have  also  the  different  alterations  in  the  secretion 
of  the  mucous  membrane  of  the  bronchiæ.  Consult  on  this  subject  : Lacnnec,  De 
l' auscultation  médiate,  Paris,  1819,  vol.  i.,  p.  124. — Andral,  Observations  sur  quelques 
altérations  organiques  des  bronches  ; in  the  Archiv,  gén.  de  méd.,  vol.  iv.,  p.  514.— 
Id.,  Clinique  médicale,  vol.  ii.,  p.  1-85. — Bree,  Recherches  sur  les  désordres  de  la 
respiration,  Paris,  1819.— Desruelles,  Traité  théorique  et  pratique  du  croup,  Paris, 
1824.  F.  T. 


Vol.  III. 


46 


358 


DESCilJPTIVK  ANATOMV. 


a.  Thickening,  induration  of  this  membrane. 

b.  Effusion  of  serum,  which  when  not  coagulable  in  a great  de- 
gree, causes  hydrothorax,  and  which  when  coagulable  produces  the 
mutual  adhesions  of  the  contiguous  surfaces  of  the  pleura.(l) 

The  principal  new  formations  in  the  lungs  are  tubercles. 

3d.  The  repetitions  of  the  normal  tissues  in  the  respiratory  organs 
are  rare.  We  must  however  refer  to  this  the  accidental  membranes 
developed  after  pleuritis,  because  they  are  repetitions  of  the  cellular 
tissue  and  the  accidental  ossifications(2)  formed  in  the  osseous  tissue. 
These  ossifications  frequently  appear  as  thin  elongated  laminæ,  si- 
tuated on  the  outer  face  of  the  pleura.  They  are  more  rare  on  the 
inner  face  of  this  membrane,  in  the  form  of  rounded  bodies,  which  at 
first  adhere,  but  are  finally  detached.  The  pretended  change  of  the 
pulmonary  substance  into  cartilage  is  probably  in  most  cases  only  an 
induration  resulting  from  effusion.  Sometimes  however  cartilaginous 
tissue  is  really  developed  accidentally  in  the  lungs. 

§ 2320.  Foreign  bodies.  These  are  : 

1st.  Entozoaries,  particularly  hydatids  which  form  in  the  substance 
or  on  the  surface  of  the  lung,  and.  the  hamularia  subcompressa  which 
exists  in  the  trachea. 

2d.  Foreign  substances  accidentally  introduced  into  the  air-pas- 
sages. 


ARTICLE  THIRD. 

CAVITY  OF  THE  THORAX. 

§ 2321.  The  thoracic  cavity  contains,  besides  the  lungs  and  their 
vessels,  the  heart,  the  commencement  of  the  aorta,  the  trunks  of  the 
ascending  and  descending  venæ-cavæ,  the  azygos  vein,  the  thoracic 
canal,  the  esophagus,  and  the  thoracic  portion  of  the  ganglionnary 
nerve.  We  have  mentioned  previously  the  manner  in  which  it  is 
formed  like  a cage.  Its  upper  extremity  is  generally  the  narrowest 
and  its  lower  extremity  the  broadest  part  of  the  chest  : at  least  it  is~ 
generally  much  broader  at  its  base  than  at  its  summit.  It  is  convex, 
on  the  sides,  flattened  forward,  larger  from  above  downward,  and 
shorter  from  before  backward  than  in  any  other  direction,  much  longer 
posteriorly  than  anteriorly,  and  provided  below  with  a more  or  less 
convex  floor  which  is  formed  by  the  diaphragm.  Posteriorly  the 
bodies  of  the  dorsal  vertebra  imperfectly  divide  it  into  two  halves. 


(1)  Laennec,  loc.  cit.,  vol.  i. — Andral,  loc.  cit.,  vol.  ii. — Id.,  Observations  sur  Vin- 
flammation  de  la  plèvre  diaphragmatique  ; in  the  Archiv,  gin.  de  mid.,  vol.  iii., 
p.  246. 

(2)  Rallier,  Note  louchant  un  Iris  grand  nombre  de  pièces  osseuses  développées 
dan s le  tissu  du  poumon  ; in  the  Archiv,  gin.  de  méd.,  vol.  v.,  p.  271. 


t 


OF  THE  RESPIRATORY  SYSTEM, 


359 


It  is  a little  shorter  on  the  right  than  on  the  left  side,  on  account  of 
the  prominence  of  the  liver. 

The  inner  face  of  its  parietes  is  covered  in  nearly  its  whole  extent  by 
the  external  layer  of  the  pleura,  which  is  there  attached  to  it  by  a very 
short  cellular  tissue.  Of  the  organs  it  incloses,  the  lungs  and  the  heart 
are  united  to  it  by  its  surrounding  serous  membranes  ; the  others  di- 
rectly by  cellular  tissue. 

The  division  into  a right' and  a left  half,  indicated  by  the  bodies  of 
the  vertebræ,  is  completed  by  the  mediastinum, 

I.  MOTIONS  OF  THE  CHEST, 

§ 2322.  The  chest  is  continually  extended,  enlarged,  contracted  ; 
and  the  first  state  occurs  in  inspiration,  and  the  second  in  expiration. 
The  motions  of  the  chest  which  determine  them,  produce  a simulta- 
neous dilatation  and  contraction  in  the  air  passages.  The  lung,  being 
compressed  when  the  chest  collapses,  expels  the  air  within  it,  while  it 
enters  through  the  mouth  and  nose,  when,  the  chest  dilating,  the  ob- 
stacle from  the  collapsing  of  its  parietes  no  longer  exists. 

The  dilatation  of  the  chest  during  inspiration,  and  its  contraction  in 
expiration,  occur  in  every  direction. 

The  greatest  change  is  that  in  height.  It  depends  partly  on  the 
depression  of  the  diaphragm  in  inspiration,  and  its  rising  in  expiration, 
partly  also  on  the  raising  of  the  ribs  by  the  intercostales  and  scaleni 
muscles. 

The  enlargement  in  the  direction  of  the  breadth,  depends  on  the  ribs 
being  drawn  outward. 

The  parietes  of  the  chest  follow  exactly  the  motions  of  the  lungs 
during  respiration,  and  these  two  parts  remain  in  contact,  at  least  in 
the  regular  state,  during  expiration  or  inspiration,  so  that  they  are 
found  in  perfect  contact  after  the  strongest  of  all  expirations,  that  which 
occurs  at  death. 


II.  DIFFERENCES  DEPENDENT  ON  SEX. 

§ 2323.  The  chest  of  the  male  is  much  larger  than  that  of  the  fe- 
male, as  it  is  longer,  broader,  and  deeper.  Its  capacity  is  also  more 
uniform,  so  that  it  is  proportionally  a little  broader,  rounder,  and  more 
movable.  The  bodies  of  the  dorsal  vertebrae  do  not  project  as  much, 

III.  DIFFERENCES  DEPENDENT  ON  DEVELOPMENT. 

§ 2324.  The  chest  is  proportionally  the  smallest  of  the  three 
sphlanchnic  cavities  of  the  body  during  the  early  periods  of  existence, 
which  depends  particularly  on  the  slight  development  and  the  inac- 
tivity of  the  lungs. 


360 


DESC  R5PTIVE  ANATOMY. 


It  possesses  in  the  same  proportion  a greater  degree  of  elasticity, 
because  the  costal  cartilages  are  much  longer  in  proportion  to  the  ribs, 
than  during  the  successive  periods.(l) 

It  does  not  begin  to  move  until  after  birth,  and  when  the  new  being 
breathes  for  the  fast  time. 

IV.  ABNORMAL  STATE. 

§ 2325.  Sometimes  the  chest  is  only  partially  closed,  from  a primi- 
tive deviation  of  formation.  When  this  anomaly  exists  on  the  anterior 
face  or  the  sides,  the  internal  organs  are  exposed  ; when  in  the  lower 
wall,  the  abdominal  and  pectoral  cavities  abnormaly  communicate,  and 
some  of  the  thoracic  viscera  enter  the  cavity  of  the  abdomen. 

The  same  also  may  be  caused  later  by  wounds,  ulcers,  &c.  A com- 
mon congenital  deviation  of  formation  is  the  abnormal  smallness  of  the 
chest,  which  generally  attends  a corresponding  defect  in  the  develop- 
ment of  the  lung,  and  a disposition  to  tuberculous  phthisis. 

The  alterations  in  the  texture  of  the  chest  are  principally  different 
kinds  of  tumors,  which  occur  in  the  mediastinum.  These  tumors  some- 
times become  large,  and  compress  the  organs  in  the  thoracic  cavity  so 
much,  that  the  subject  dies  from  the  suspension  of  the  circulation  or  nu- 
trition. (2) 


ARTICLE  FOURTH. 

GLANDULAR  ORGANS  SITUATED  NEAR  THE  ORGANS  OF  VOICE 
AND  RESPIRATION. 

§ 2326.  We  find  near  the  organs  of  voice  and  respiration,  two  im- 
perfect glands, (3)  the  thyroid  and  the  thymus  glands,  which  are  simi- 
lar, not  only  as  they  both  present  the  general  characters  of  glands  of 
their  species,  but  also  because  they  are  situated  directly  on  the  median 
line,  behind  the  anterior  face  of  the  body,  before  the  organs  of  respira- 
tion, and  because  they  even  touch  in  the  early  periods  of  fetal  existence. 

These  two  glands  possess  numerous  blood-vessels  and  lymphatics. 
They  have  no  excretory  ducts,  but  contain  in  their  spaces  a fluid  dif- 
ferent from  their  substance,  and  which  is  very  evident  in  the  thymus 
gland.  The  change  of  a considerable  quantity  of  blood,  which  is  pro- 

(1)  Compare  the  measures  in  regard  to  this. subject,  in  Lohstein,  Sur  la  première 
inspiration  de  Venfanl  nouveau  nc  ; in  the  Journal  de  médecine , vol.  xxxv.  p.  311- 
312. 

"(2)  Lænnec,  Sur  le  rétrécissement  de  la  poitrine  à la  suite  de  certaines  pleurésies  : 
in  his  V Auscultation  médiate,  vol.  i.  p.  369. 

(3)  P.  H.  Bœcklen,  De  thyroideœ,  Ihymi  et  glana lularum  sùjnarenaliumfunctionî- 
bus,  Strasburg1 * 3, 1753. — J.  F.  Meckel,  Lieber  die  Schilddrüse,  Nebennieren  und  einige 
ihnen  verwandte  Organe  ; in  his  Abhandlungen  aus  der  menschlichen  und  ver- 
gleichenden Anatomie,  Halle,  1816,  p.  1-277. 


OF  THE  RESTIRATORY  SYSTEM. 


361 


bably  peculiarly  modified,  and  the  formation  of  their  fluid,  are  the  only 
functions  which  can  be  assigned  to  them  with  certainty.  We  then 
have  reason  to  think  their  functions  in  the  sanguineous  system  are 
analogous  to  those  of  the  lymphatic  vessels,  that  is,  they  are  organs 
which  contribute  to  perfect  the  formation  of  blood.  This  conjecture  is 
rendered  probable  from  the  fact,  that  the  blood  which  passes  through 
their  tissue,  and  the  fluid  which  they  prepare,  soon  enter  the  venous 
blood  near  its  entrance  into  the  lung. 

I.  THYROID  GLAND. 

A.  PERFECT  STATE. 

§ 2327.  The  thyroid  gland  (G.  thyroidea){  1)  is  situated  forward 
and  on  the  sides  of  the  upper  part  of  the  trachea  and  pharynx. 

It  is  composed  of  a centre,  which  is  slightly  contracted,  thin,  and 
about  four  lines  high,  termed  the  isthmus , and  of  two  lateral  portions 
or  horns,  which  are  directed  from  below  upward,  and  terminate  in  a 
point. 

The  central  part  is  situated  directly  below  the  larynx,  and  before  the 
three  or  four  upper  rings  of  the  trachea.  The  two  horns  extend  below 
to  the  sixth  or  seventh  ring,  and  above  to  the  lower  horn  of  the  thyroid 
cartilage. 

There  is  generally  detached  more  or  less  from  its  centre,  a median 
horn,  which  is  generally  single,  rarely  double,  termed  by  Lalouette  the 
pyramid.  This  horn  is  rarely  perfectly  cylindrical,  and  generally  cor- 
responds to  the  left  side  more  than  to  the  right, (2)  which  deserves  to 
be  remarked  on  account  of  the  greater  development  cf  the  hyoid  bone, 
generally  occurring  on  the  same  side.  It  reascends  before  the 
thyroid  cartilage  to  the  middle  hyoid  bone,  and  it  terminates  there, 
gradually  becoming  thinner.  This  horn  exists  more  frequently  than 
it  is  deficient. (3)  We  must  then  attribute  to  accident,  or  to  careless 
dissection,  the  assertions  of  authors  to  the  contrary. (4) 

§ 232S.  It  is  generally  surrounded  by  a special  and  unmated  muscle, 
the  levator  gland,  thyroideœ  muscle,  the  upper  extremity  of  which  is 
generally  attached  to  the  body  of  the  hyoid  bone  ; sometimes  it  does 

(1)  P.  Evertze,  De  glandulâ  thyroideâ,  Leyden,  1708. — Santorini,  Obs.  anat.,  ch. 
vi-xvii.- — Duvernoy,  Obs.  anat.,  2,  3,  4 ; in  the  Comm.  Petrop.,  vol.  vii.  1740,  p.  216- 
218. — Lauth,  De  glandula  thyroideâ,  Strasburg-,  1742.— Morgagni,  Ep.  anat., 
Venice,  1763,  vol.  ix.'§  30^10. — Uttini,  De  glandules  thyroideœ  usu  : in  the  Comm. 
Bonon.,  vol.  vii.  p.  15-23. — Lalouette,  Recherches  anatomiques  sur  la  glande  thy- 
roïde ; in  the  Mem.  prés.,  vol.  i.  1750,  p.  159-175. — Gunz,  Obs.  anat.  I.  sur  la  glande 
thyroids,  ibid.,  p.  283-284. — Schmidtmuller,  Leber  die  Ausfuhrungsgange  der 
Schilddrüse,  Landshut,  1804. — B.  Hofrichter,  Mémoire  sur  la  thyroïde,  in  the  Journ. 
compl.  des  sc.  méd.,  \ ol.  x.  p.  21. 

(2)  Duvernoy,  loc.  cil. — Lalouette,  loc.  cit.,  p.  163. — Morgagni,  Ep.  IX.  a.  34. — 
Schmidtmuller,  loc.  cit. 

(3)  We  have  most  generally  found  it,  and  Morgagni  (Ep.  anat.  x.  a.  36)  has  ob- 
served it  to  be  absent  only  six  times  in  a great  many  cadavers. 

(4)  Schmidtmuller,  loc.  cit.,  p.  29. 


362 


DESCRIPTIVE  ANATOMY. 


not  extend  so  high,  and  is  inserted  in  the  lower  edge  of  the  thyroid  car- 
tilage. In  the  latter  case  the  middle  horn  is  very  slightly  developed. 

This  muscle  participates  in  the  asymmetrical  arrangement  of  the 
middle  horn  of  the  thyroid  gland,  so  that  it  generally  belongs  to  the 
left  half  of  this  latter,  more  than  to  its  right  portion  : it  however  is  not 
always  attached  to  the  same  side  of  the  hyoid  bone,  or  of  the  thyroid 
cartilage,  but  sometimes  passes  obliquely  before  the  trachea  or  the 
larynx,  to  arrive  at  the  opposite  side.  This  arrangement,  which  ap- 
parently renders  it  still  less  symmetrical,  although  it  really  tends  to 
re-establish  the  symmetry,  occurs  particularly  when  it  is  attached  to 
the  thyroid  cartilage,  and  is  then  inserted  in  its  inner  edge,  on  the  out- 
side of  the  crico-thyroideus  muscle. 

§ 2329.  Each  of  the  lateral  horns  is  generally  two  inches  high, 
while  the  height  of  the  isthmus  is  only  one  inch.  The  entire  breadth 
of  the  gland  is  about  eight  inches  ; that  of  each  horn  is  nine  lines. 
The  whole  gland  weighs  about  one  ounce. 

2330.  The  thyroid  gland  is  of  a dirty  red  color;  its  texture  is  firm 
and  solid,  its  surface  is  smooth.  It  has  no  proper  capsule,  and  is  sur- 
rounded only  by  a condensed  cellular  tissue  ; it  is  composed  of  large 
and  small  rounded,  irregular  lobes,  each  enveloped  by  a cellular  sheath, 
between  which  the  vessels  are  distributed.  It  normally  contains  no 
cavity  ; however,  when  we  make  an  incision,  either  into  the  lobes  or 
between  them,  a fluid  analogous  to  the  serum  of  the  blood,  oozes  in 
great  abundance  from  the  wound. 

§ 2331.  For  a long  time  it  has  been  disputed  whether  the  thyroid 
gland  has  excretory  ducts  1 

Several  anatomists,  as  Vater, (1)  Santorini, (2)  Coschwitz,(3)  and 
Schmidtmuller,(4)  have  thought  they  saw  one  or  more  passages 
which  extended  from  the  gland  into  the  larynx  or  trachea.  They  have 
attempted  to  consider  the  middle  horn  as  an  excretory  canal,  both  from 
its  form  and  the  openings  in  the  larynx  on  a level  with  its  upper  extre- 
mity. But  the  observations  in  support  of  this  opinion  are  so  trivial, 
and  the  most  distinguished  anatomists  who  have  made  them,  have 
thought  them  of  so  little  importance,  that  as  yet  we  have  reason  to 
consider,  with  Duvernoy,  Morgagni,  and  others,  the  thyroid  gland  as 
having  no  excretory  passage,  or  none  except  the  lymphatic  vessels. 

As  the  thyroid  gland  is  proportionally  much  larger  during  the  early 
periods  of  life,  and  as  particularly  its  middle  horn  is  then  much  more 
developed  than  in  the  adult,  perhaps  the  excretory  canal  exists  at  this 
period,  and  is  obliterated  as  the  development  of  the  gland  is  arrested, 
so  that  the  imperfect  development  of  the  glands  from  a deviation  in 
formation,  often  results  from  the  absence  or  obliteration  of  their  ex- 
cretory passages. 

(1)  Denov.  duct,  saliv.  in  lingua,  humana;  in  Haller,  Coll,  diss .,  vol.  i.  p.  63. 

(2)  Loc.  cit.,  p.  115. 

(3)  Ductus  salivai,  novus  plurib.  observ.  illustr Halle,  1729,  p.  10. 

(4)  Loc.  cit.,  p.  45-51. 


OF  THE  RESPIRATORY  SYSTEM. 


363 


B.  DIFFERENCES  RELATIVE  TO  SEX. 

§ 2332.  The  thyroid  gland  is  more  developed  in  the  female  than  in 
the  male,  which  constitutes  a very  remarkable  sexual  difference. 

C.  DIFFERENCES  DEPENDENT  ON  DEVELOPMENT. 

§ 2333.  The  thyroid  gland  is  at  first  formed  of  two  separate  glands, 
one  of  which  is  much  larger  proportionally  than  it  is  when  the  body  is 
entirely  developed,  softer,  more  vascular,  and  consequently  redder.  Its 
middle  horn,  particularly,  is  much  larger  than  it  is  subsequently. 

D.  ABNORMAL  STATE. 

§ 2334.  The  thyroid  gland  is  sometimes,  but  very  rarely,  as  Mor- 
gagni has  remarked, (1)  divided  into  two  distinct  and  separate  halves. 
This  anomaly  is  very  remarkable  on  account  of  its  relations  with  the 
state  of  the  organ  in  the  early  periods  of  fetal  existence,  and  because  it 
occurs  normally  in  most  mammalia.  An  arrangement  resembling  it, 
is  the  considerable  narrowness  of  the  central  portion  or  of  the  isthmus. 
Sometimes  only  a portion  of  a lobe  is  separated  from  the  rest  of  the 
gland. (2) 

Rather  a common  deviation  of  formation,  but  which  is  most  gene- 
rally consecutive,  and  rarely  congenital,  is  the  enlargement  of  the  thy- 
roid gland,  which  constitutes  goitre  ( struma ) ; this  is  frequently  enor- 
mous, and  is  endemic  in  the  narrow  valleys  of  mountainous  countries: 
The  goitre,  however,  by  no  means  always  depends  simply  on  an  in- 
crease in  the  size  of  the  thyroid  gland  : it  is  frequently  only  a conse- 
quence of  the  development  of  new  formations  in  the  tissue  of  this  organ, 
or  at  least  presents  a conplication  of  the  two  states. 

Hypertrophy  of  the  thyroid  gland,  when  not  endemic,  is  much  more 
frequent  in  females  than  in  males.  It  appears  particularly  at  puberty, (3) 
gestation,  parturition,  and  lying  in. 

The  abnormal  formations  occurring  in  the  thyroid  gland,  are  princi- 
pally repetitions  of  normal  organic  elements,  as  serous  cysts  filled  with 
different  fluids,  also  cartilages,  fibro-cartilages,  and  bones  : all  these 
formations  frequently  coexist. 

§ 2335.  From  what  precedes,  it  follows,  as  we  have  already  re- 
marked, that  in  its  situation  and  form,  the  thyroid  gland  is'a  repetition, 
in  the  upper  half  of  the  bodj»,  of  the  uterus  and  prostate  gland.  This 


(1)  Ep.  IX.  a.  30. 

(2)  Haller,  El.  physiol.,  vol.  iii.  p.  396. 

(3)  Journal  de  médecine  de  Sédillot,  vol.  lvii.  p.  416.  We  there  read  the  remark- 
able case  of  a boy  fourteen  years  old,  in  whom  the  thyroid  gland  was  so  much  swelled, 
without  any  external  cause,  as  to  produce  suffocation. 


364 


DESCRIPTIVE  ANATOMY, 


analogy  seems  to  us  more  just,  because  we  frequently  remark  the  same 
anomalies  in  both  these  parts  at  the  same  time  in  the  same  subject. 

II.  THYMUS  GLAND. 

A.  NORMAL  STATE. 

§ 2336.  The  thymus  gland  ( Gl . thymus , s.  corpus  thymianum)(\) 
is  an  irregular  square  or  quadrilateral  body,  the  base  of  which  looks 
downward,  and  the  summit  upward,  which  occupies  the  upper  and 
anterior  part  of  the  anterior  mediastinum,  where  it  is  situated  directly 
behind  the  sternum,  before  the  base  of  the  heart  and  the  large  vessels. 
It  as'cends  also  more  or  less  out  of  the  chest  for  about  half  an  inch,  and 
extends  on  the  anterior  face  of  the  neck,  where  it  is  covered  by  the 
sterno-hyoidei  and  sterno-thyroidei  muscles. 

Its  height  and  breadth  much  exceed  its  thickness. 

Its  length  generally  exceeds  its  breadth.  Although  it  gradually 
contracts  towards  its  summit,  it  however  generally  presents  a more  or 
less  considerable  prominence  at  its  upper  extremity. 

§ 2337.  Its  color  is  reddish  white,  and  it  is  soft. 

Its  vessels,  which  are  not  very  large,  arise  anteriorly,  enter  it  from 
above  downward,  from  behind  forward,  and  from  before  backward. 
But  each  of  its  lobes  has  not  a special  trunk,  and  receives  vessels  from 
several  regions  at  once. 

§ 2338.  Beside  an  external  envelop,  which  is  given  to  it  by  the  an- 
terior mediastinum,  the  thymus  gland  has  still  a less  dense  or  less  solid 
proper  cellular  capsule,  below  which  the  fat  collects  here  and  there  in 
corpulent  persons,  but  does  not  accumulate  in  any  great  quantity. 

After  removing  this  capsule,  the  thymus  gland  is  itself  divided  into 
a right  and  a left  half.  Its  two  lateral  lobes  are  attached  only  by 
very  loose  cellular  tissue,  and  by  the  vessels  which  penetrate  them,  so 
that  it  would  be  more  correct  to  admit  two  thymus  glands. 

These  two  halves,  which  are  also  triangular,  and  the  two  internal 
faces,-  are  situated  one  against  another  in  their  whole  extent,  are  simi- 
lar in  form  and  volume,  but  are  not  exactly  alike  : one  of  them  is  some- 
times about  one  tenth  larger  and  heavier  than  the  other. 

The  external  envelop  of  the  thymus  gland  will  show  that  its  surface 
is  not  smooth  and  uniform,  but  divided  into  several  larger  and  smaller 
lobes,  which  are  composed  of  smaller  lobules,  separated  less  deeply 
from  each  other,  between  which  the  two  external  envelops  do  not 

• ' 

(1)  G.  E.  Mctzg-er,  Hist.  anal.  med.  thy'mi,  Tubingen,  1679. — G.  H.  Muller,  De 
glandula  thymo,  Leyden,  1705. — Verheyen,  Dc  tliymo,  Leyden,  1706. — G.  Bidloo, 
Defens,  exer de  thymo , Leyden,  1707. — J.  G.  Duvernoy,  in  the  Comm.  Petrop.,  vol. 
vii.— A.  L.  de  Hugo,  De  glandidis  et  speciatim  de  thymo , Gottingen,  1746. — G.  Hew- 
son,  Experimental  inquiries , part  iii.  London,  1717. — Lucse,  Anatomische  Unter* 
su/hungen  der  Thymus  in  Menschen  und  Thieren,  Frankfort,  1811-12, 


OF  THE  RESPIRATORY  SYSTEM. 


365 


penetrate  more  than  between  the  two  great  lateral  lobes,  and  which 
are  united  only  by  a loose  cellular  tissue  and  by  vessels. 

§ 2339.  On  cutting  the  thymus  gland,  there  flows  out  spontaneously, 
or  by  pressure,  a fluid,  differing  from  its  own  substance,  more  or  less 
abundant,  thick  and  whitish,  similar  to  that  which  exists  in  the  ru- 
minantia,  between  the  fetal  and  maternal  portions  of  the  placenta. 

Opinions  differdn  regard  to  the  relations  between  this  liquid  and  the 
substance  of  the  organ.  With  this  question  is  connected  another  : Is 
the  thymus  gland  hollow  % 

Many  anatomists  assert  there  is  no  cavity  in  the  gland,  and  this 
fluid  is  consequently  contained  in  its  substance.  Others  think  that  the 
lobules  alone  are  really  hollow.  Finally,  some  admit  a great  cavity 
the  parietes  of  which  are  formed  by  the  substance  of  the  organ. 

We  maintain  the  latter  opinion  : for  in  examining  very  recent  thy- 
mus glands,  we  have  several  times  observed  either  on  cutting  them 
or  slightly  inflating  them,  a large  cavity  in  each  of  the  two  lateral 
lobes.  This  cavity  is  lined  by  a thin  and  smooth  membrane.  It  com- 
municates with  those  in  the  lobules,  and  contains  a great  quantity  of 
the  fluid  mentioned  above. 

Sometimes,  however,  this  cavity  is  less  apparent,  so  that  very  pos- 
sibly the  internal  arrangement  of  the  thymus  gland  is  not  always  per- 
fectly the  same.  Thus,  in  some  cases,  the  lateral  cavities  are  divided 
into  several  compartments  by  intermediate  septa.  Sometimes,  how- 
ever, we  find  the  arrangement  maintained  by  the  partisans  of  the 
second  opinion  to  be  constant,  and  to  which  the  preceding  impercep- 
tibly leads. 

§ 2340.  The  thymus  gland  does  not  continue  to  exist  during  life. 

It  is  first  seen  in  the  third  month  of  gestation. 

It  is  at  first  proportionally  smaller  than  at  a more  advanced  period, 
and  its  proportional  size  increases  till  the  moment  of  birth. 

In  the  full-grown  fetus  it  weighs  half  an  ounce,  and  sometimes  a 
drachm  more  when  the  child  is  vigorous  and  strong. 

Its  upper  part  appears  first,  and  it  enlarges  from  above  downward. 

Although  it  is  not  proportionally  as  large  until  the  end  of  the  first 
year,  and  sometimes  even  till  that  of  the  second,  it  continues  to  grow 
during  all  this  period  in  the  same  proportion  as  in  the  full  grown  fetus. 

But  at  this  period  it  wastes,  its  vessels  contract,  and  the  fluid  it  se- 
cretes diminishes.  It  disappears  in  a direction  opposite  to  that  in 
which  it  was  formed,  that  is  from  below  upward. 

At  twelve  years  of  age  we  find  no  trace  of  it,  and  it  is  then  replaced 
by  fat. 

From  this  we  may  conclude  that  it  does  not  exist  except  for  about 
the  fifth  part  of  life,  and  that  the  energy  of  its  function  declines  long 
before  it  disappears.  Its  most  flourishing  period  is  -consequently  very 
different  from  that  at  which  most  other  organs  have  attained  their 
greatest  development. 


VOL.  III. 


47 


3C6 


DESCRIPTIVE  ANATOMY. 


§ 2341.  We  have  already  mentioned  in  a general  manner  its  func- 
tions : several  circumstances  lead  us  to  think  it  is  very  intimately  con- 
nected with  respiration,  and  more  or  less  replaces  it.  We  may,  how- 
ever, easily  reconcile  the  two  conjectures,  since  from  what  we  have 
said  above,  the  use  of  the  thymus  gland,  is  to  prepare  for  the  perfect 
formation  of  the  blood  by  respiration. 

B.  ABNORMAL  STATE. 

§ 2342.  The  greatest  anomaly  of  the  thymus  gland  is  its  absence, 
which  is  generally  observed  in  acephalia  vera. 

Its  smallness,  when  the  organ  is  perfectly  developed  in  respect  to  the 
number  of  its  parts,  is  commonly  attended  with  a languid  state  in  nu- 
trition generally.  We  have  sometimes  seen  this  anomaly  also  in  ace- 
phalia falsa. 

The  thymus  gland  is  rarely  in  this  case  divided  into  several,  even  as 
many  as  five  lobes.(l) 

Its  continuance  at  the  degree  of  development  which  characterizes  it 
in  the  early  periods  of  life,  sometimes  attends  abnormal  formations  of 
the  heart,  and  those  states  of  the  lungs  which  prevent  the  perfect  for- 
mation of  the  blood. (2)  This  then  supports  our  opinion  advanced  above 
in  regard  to  its  functions. 

As  this  organ  disappears  very  early,  alterations  in  its  texture  are 
proportionally  rare.  We  may,  however,  mention  as  such,  different 
kinds  of  tumors,  although  in  many  cases  those  mentioned  by  authors 
are  developed  only  in  the  place  occupied  by  the  thymus  gland,  and 
after  it  has  disappeared. 

CHAPTER  III. 

OF  THE  URINARY  SYSTEM  AND  RENAL  CAPSULES, 
ARTICLE  FIRST. 

URINARY  SYSTEM. 

A.  PERFECT  STATE. 

§ 2343.  The  urinary  organs  ( organa  uropoetica)(3 ) are  composed 
of  four  parts  destined,  to  secrete,  carry,  preserve,  and  excrete  the  urine, 

(1)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  i.  p.  488. 

(2)  Meckel,  Abhandlungen , p.  234. 

(3)  G.  Bendt,  Defabrica  et  usu  viscerum  uropoeticorum,  Leyden,  1744. — J.  Fan- 
toni,  De  renibus  et  primum  de  succenturiatis,  de  ureteribus  et  vesica,  Turin,  1745. — 
A.  Richerand,  Mémoire  sur  V appareil  urinaire  ; in  the  Mém.  de  là  soc.  méd.  d'émul. 
vol.  iv.  p.  303. 


OF  THE  URINARY  SYSTEM. 


367 


viz.  the  kidneys,  the  ureters , the  bladder,  and  the  urethra.  The  last 
three  organs  may  be  opposed  to  the  first.  These  are  entirely  excre- 
tory organs,  for  they  carry  nothing  which  can  be  useful  to  the  organ- 
ism, remove  from  the  body  an  excess  of  azote,  which  is  the  base  of  the 
most  essential  constituent  principle  of  the  urine,  the  urea , and  cor- 
respond in  form  and  situation  in. the  lower  half  of  the  body,  to  the  re- 
spiratory organs  in  the  upper. 

Ï.  KIDNEYS.. 

A.  NUMBER  AND  SITUATION. 

§ 2344.  The  kidneys  (renes),(  1)  the  most  essential  part  of  the  uri- 
nary apparatus,  are  double  in  the  normal  state,  a right  and  a left  ; they 
are  entirely  distinct  from  each  other,  having  no  communication  in  sub- 
stance, and  connected  in  one  system  only  by  means  of  the  bladder. 
They  are  situated  in  the  lumbar  region,  on  the  two  sides  of  the  verte- 
bral column,  behind  the  peritoneum,  and  are  connected  with  the  adja- 
cent parts  only  by  loose  cellular  tissue. 

B.  FORM. 

§ 2345.  They  have  the  form  of  a bean.  Their  anterior  and  pos- 
terior faces  are  smooth.  Their,  external  and  internal  edges  are  convex 
in  their  upper  and  lower  parts,  but  in  their  centres  is  a considerable 
depression,  termed  the  fissure  of  the  kidney  (hilus  renalis).  The  kid- 
ney is  divided  in  this  part  for  about  half  an  inch,  into  an  anterior  and  a 
posterior  half,  between  which  pass  the  excretory  duct  and -the  blood- 
vessels. The  blood-vessels  are  arranged  so  that  the  venous  trunk  is 
situated  before,  and  followed  by  that  of  the  artery,  behind  which  the 
ureter  commences. 

The  branches  of  the  renal  artery  and  vein  intercross. 

When  the  three  vessels  have  arrived  at  the  fissure  of  the  kidney, 
they  divide  near  the  inner  edge  of  the  gland  into  three  principal 
branches,  which  soon  ramify.  The  blood-vessels  then  divide  into  two 
series,  an  anterior  and  a posterior,  which  receive  the  vessels  of  the 
pelvis. 

(1)  B.  Eustachi,  De  renibus  libellus,  Venice,  1543. — J.  Lœsel,  Scrutinium  renum, 
Königsberg-,  1642.— M.  Malpighi,  De  renibus,  in  ex.  de  viscerum  structura. — L. 
Bellini,  De  structura  renum,  Florence,  1662.— Bertin,  Mémoire  pour  servir  a l’ his- 
toire des  reins,  in  the  Mémoires  de  Paris,  1745,  p.  108. — A.  Ferrein,  Sur  la  structure 
des  viscères  nommés  glanduleux,  et  particuliérement  sur  celle  des  reins  et  du  foie  ; 
in  the  Mém.  de  Paris,  1749,  p.  709.— J.  F.  Droysçn,  De  renibus  et  capsulis  renalibus, 
Gottingen,  1752. — A.  Schumlanski,  De  structura  renum , Strasburg,  1788. — C..G. 
Eysenhardt,  De  structura  renum  observaliones  microscopicce,  Berlin,  1818. — A.  H. 
C.  Westrumb,  Comment,  phys.  de  phœnomenis  quæ  ad  vins  sic  dictas  lotii  clandes- 
tinas  demonstrandas  referentur,  Gottingen,  1819.— Mappes,  Quelques  considéra- 
tions sur  la  structure  du  rein  et  du  foie  ; in  the  Journ.  compl.  des  sc.  méd.  vol.  xii. 
p.  223. 


363 


DESCRIPTIVE  ANATOMY. 


All  these  vessels  are  united  in  the  fissure  of  the  kidney  only  by  a 
very  loose  cellular  tissue  and  by  fat. 

Three  particularly  enter  and  emerge  through  the  upper  part  of  the 
renal  fissure,  the  lower  part  of  which  is  occupied  by  the  pelvis. 

C.  VOLUME  AND  WEIGHT. 

§ 2346.  The  proportional  size  of  the  kidneys  varies.  Generally 
these  organs  are  larger  the  .nearer  the  fetus  is  to  its  period  of  forma- 
tion : they  however  present,  even  under  this  point  of  view,  individual 
differences,  which  are  independent  of  the  age,  and  which  seem  to  re- 
late to  the  size  and  energy  of  the  other  excretory  organs. 

Generally  speaking,  the  two  kidneys  are  equal  in  size  : both,  how- 
ever, frequently  vary  extremely,  although  the  side  of  the  body  has  no 
effect  upon  it.  The  ancients  asserted  that  the  right  kidney  is  always 
larger  than  the  left,  which  is  incorrect. 

In  the  adult’ they  are  about  four  inches  long  and  two  broad.  They 
are  about  an  inch  thick  at  their  inner  part,  but  are  thinner  outward. 

Each  of  them  weighs  between  three  or  four  ounces. 

D.  CONSISTENCE  AND  COLOR. 

§ 2347.  The  kidneys  are  much  harder  than  the  other  glands,  and 
are  firmer,  more  solid,  and  less  easily  torn. 

They  are  generally  reddish. 

E.  STRUCTURE. 

§ 2348.  They  are  surrounded  by  a very  loose  cellular  tissue,  most 
generally  abundantly  provided  with  fat,  and  termed  the  adipose  mem- 
brane., or  capsule  of  the  kidney  (mem.  s.  capsula  renum  adiposa ). 

We  find  below  this  cellular  mass  a whitish  membrane,  reddish  on 
its  two  faces,  the  texture  of  which  is  not  evidently  fibrous,  but  which 
is  very  solid,  and  resembles  the  fibrous  membranes.  This  capsule  en- 
velops the  entire  kidney  ; it  only  presents  an  opening  corresponding  to 
the  fissure,  for  the  passage  of  the  blood-vessels  and  the  excretory  duct, 
and  it  adheres  intimately  in  its  whole  extent  to  the  substance  organ, 

F.  TEXTURE. 

§ 2349.  The  kidneys  are  formed  of  two  substances,  which  differ 
much  in  color,  situation,  consistence,  and  texture.  They  are  the  corti- 
cal or  glandular  substance  ( substantia  corticalis , s.  glandtdosa ),  and 
the  medullary , tubular , or  fibrous  substance  ( s . medullaris , tubulosa,  s. 
fibrosa). 

§ 2350.  The  cortical  surrounds  the  medullary  substance  in  most  of 
its  extent,  and  in  every  direction.  It  not  only  forms  entirely  the  outer 


OF  THE  URINARY  SYSTEM. 


369 


face  of  the  kidney,  but  extends  also  to  its  inner  face  by  several  arched 
prolongations,  between  which  the  medullary  substance  is  situated.  It 
consequently  forms  a collection  of  cavities,  united  by  a common  base, 
the  culs-de-sac  of  which  are  turned  outwaid. 

Thus  the  cortical  substance  forms  the  external  and  colored  part  of 
the  kidney  ; it  is  about  two  or  three  lines  thick  : its  color  is  redder  than 
that  of  the  medullary  substance,  and  it  is  much  less  consistent. 

It  is  composed  principally  of  blood-vessels  and  glandular  bodies, 
which  are  the  organs  of  the  urinary  passages.  The  urine  is  secreted 
in  it. 

§ 2351.  The  medullary  substance  is  inclosed  in  the  preceding,  and  is 
composed  of  a mass  of  rounded,  conical,  or  pyramidal  bodies  ( pyramides 
malpighianœ ),  the  bases  of  which  are  turned  outward,  and  the  blunt 
summits  inward  ; if  we  except  the  most  internal  part,  which  is  only 
some  lines  high  and  broad,  and  which  constitutes  the  renal  papilla 
{papilla  renales ),  it  is  entirely  enveloped  by  medullary  substance. 

It  opens  in  this  place  into  the  commencement  of  the  ureter  or  pelvis. 

The  summit  of  the  renal  papillæ  usually,  but  not  always,  presents  a 
greater  or  less  number  of  rounded  openings,  which  although  small,  are 
visible  to  the  naked  eye.  The  papillæ,  which  have  a depression,  pre- 
sent openings  only  in  this  groove,  while  in  those  which  terminate 
simply  in  a point,  the  foramina  are  arranged  around  the  summit. 

The  loose  extremity  of  these  papillæ  is  covered  by  thick  envelops, 
which  is  continuous  with  the  inner  membrane  of  the  pelvis. 

The  number  of  these  papillæ  varies  from  seven  to  twenty.  They 
are  distributed  in  three  series,  a middle,  an  anterior,  and  a posterior,  all 
of  which  are  directed  from  above  downward.  Those  of  the  inner  series 
are  turned  inward  towards  the  median  line  of  the  body  : those  of  the 
anterior  go  backward,  and  those  of  the  posterior  forward,  that  is  in  a 
direction  opposite  to  the  preceding.  The  superior  go  downward  in 
every  direction. 

Sometimes  the  papillæ,  which  are  entirely  distinct  at  their  base,  unite 
and  blend  at  their  summit. 

The  medullary  substance  is  less  red  and  much  harder  than  the  cor- 
tical. 

It  is  composed  of  blood-vessels,  but  particularly  of  straight  urinary 
passages,  with  which  the  foramina  of  the  papillæ  communicate. 

The  urine  is  secreted  in  it,  as  when  it  is  compressed,  this  fluid  es- 
capes from  the  excretory  passages  which  form  most  of  it,  through  the 
foramina  of  the  papillæ. 

§ 2552.  From  this  description  it  follows  that  the  kidneys  are  com- 
posed of  about  fifteen  segments,  termed  lobules  (lobuli  renales , s.  ren- 
culi ),  each  of  which  is  formed  in  turn  of  medullary  and  of  cortical  sub- 
stance, and  the  cortical  envelops  of  which  are  continuous  with  each 
other. 

§ 2353.  The  intimate  structure  of  the  kidneys  is  demonstrated  by 
maceration,  injection,  and  the  microscope. 


370 


DESCRIPTIVE  ANATOMY. 


§ 2354.  The  surface  of  the  cortical  substance  is  not  smooth,  but 
seems  formed  by  numerous  irregular,  rounded,  quadrangular,  penta- 
gonal, or  hexagonal  spaces,  arranged  very  compactly,  which  are  not 
half  a line  in  diameter.  These  spaces  are  confined  by  small  vessels, 
which  send  branches  within  them  : they  consequently  have  a brighter 
color  than  that  of  their  edges,  which  are  formed  by  these  vessels. 

We  also  find  in  every  part  in  the  cortical  substance,  rounded  cor- 
puscles, appearing  to  the  naked  eye  as  very  small  points.  These  cor- 
puscles depend  on  the  most  minute  ramifications  of  the  blood-vessels, 
particularly  the  arteries,  andin  connection  with  them  they  have  the 
form  of  a bunch  of  grapes. 

• Some  anatomists,  especially  Malpighi,  Bertin,  and  Schumlansky, 
consider  them  as  special  organs,  different  from  the  branches  of  the  ves- 
sels, as  glands  or  bursts,  on  the  parietes  of  which  the  vessels  are  dis- 
tributed. Farther,  authors  are  not  agreed  in  respect  to  them,  for  Bertin 
has  described  and  figured  -them  much  larger  than  those  admitted  by 
Malpighi,  while  the  observations  of  Schumlansky,  from  which  those 
pf  Eysenhardt  do  not  essentially  differ,  agree  with  the  assertions  of 
Malpighi.  Others,  as  Ruysch,  consider  these  corpuscles  not  as  glands, 
but.  as  branches  of  vessels. 

It  is  more  probable  that  they  are  formed  by  the  twigs  of  the  arteries, 
and  by  the  roots  of  the  excretory  passages  in  the  cortical  substances, 
united, by  a mucous  tissue,  and  that  they  are  not  hollow.  In  this  man- 
ner the  two  opinions  may  be  reconciled. 

The  urine  is  undoubtedly  formed,  at  least  in  great  part,  in  these  cor- 
puscles. 

They  seem  not  to  have  a special  envelop,  and  they  are  formed,  at 
least  generally,  by  a single  arterial  twig. 

They  are  not  seen  to  communicate  distinctly  with  the  veins,  al- 
though the  transition  of  them  to  the  arteries  is  easity  perceived. 

§ 2355.  Besides  these  glandular  corpuscles,  the  vascular  ramifica- 
tions to  which  we  shall  return  hereafter,  and  finally  the  soft  and  whitish 
tissue  which  unites  all  these  parts,  and  to  which  Ferrein  particularly 
has  called  the  attention  of  anatomists,  the  cortical  substance  also  in- 
cludes numerous  small,  white,  and  very  tortuous  canals,  called  the 
cortical  canals , or  ducts  of  Ferrein  ( C . corticales).  These  passages 
frequently  anastomose  together,  usually  proceed  separately,  sometimes 
unite  in  pairs,  and  circumscribe  small  and  infinitely  varied  spaces. 
They  compose  most  of  the  cortical  substance,  and  are  very  probably 
the  excretory  canals  of  the  corpuscles  above  mentioned. 

These  canals  are  tortuous  in  the  cortical  substance,  but  become 
straight  in  the  medullary  substance.'  When  looked  at  attentively  we 
observe  here  and  there  that  the  change  in  direction  regularly  com- 
mences rather  high,  some  distance  from  the  surface  of  the  kidney,  so 
that  the  cylindrical  prolongations  of  the  medullary  and  the  cortical 
substance  reciprocally  penetrate  in  numerous  points. 

The  cortical  canals  are  single,  and  always  have  the  same  diameter 
in  the  cortical  substance  ; but  they  gradually  unite  in  the  medullary 


OF  THE  URINARY  SYSTEM. 


371 


substance  in  the  form  of  angles  acute  at  the  base,  into  several  trunks, 
which  generally  are  not  much  larger  than  they,  and  proceed  side  by 
side  toward  the  summit  of  the  papillæ  ; but  according  to  some  anato- 
mists, particularly  Ferrein  and  Eysenhardt,  they  do  not  extend  to  the 
openings  in  these  papillæ,  but  terminate  before  arriving  there.  The 
same  writers  add  that  the  openings  of  the  papillæ  only  lead  into  small 
culs-de-sac  about  one  or  two  lines  deep,  which  like  them  are  much 
broader  than  the  canals  of  which  we  speak , and  also  fewer,  there 
being  according  to  Ferrein,  twenty  in  each  papilla. 

We  have  sometimes  seen  very  distinctly  some  canals  which  ex- 
tended entirely  through  the  renal  papillæ,  so  that  we  admit  a direct 
continuity  between  the  urinary  passages  and  the  openings  of  the  pa- 
pillary eminences.  We  are  more  disposed  to  adopt  this  opinion,  as  it 
is  very  easy  to  inflate  the  passages  through  the  papillæ,  since  in  large 
animals  even  an  injection  passes  from  the  artery  into  the  whole  pa- 
pilla, and  urine  is  pressed  out  from  it  in  compressing  the  cortical  sub- 
stance. 

§ 2356.  Each  lobule  of  the  kidneys  then  is  composed  of  several 
masses  of  canals,  which  are  at  first  tortuous,  then  straight,  arranged 
very  compactly,  which  have  their  base  turned  upward,  their  summit 
downward,  but  represent  the  form  of  the  whole,  and  are  only  more 
elongated. 

The  right  part  of  these  canals,  which  is  contained  in  the  medullary 
substance,  has  long  been  known,  for  it  is  mentioned  by  Berenger  de 
Carpi  ; but  it  is  described  most  correctly  by  Bellini  : hence  they  are 
termed  the  ducts  of  Bellini  ( ductus , s.  tubuli  Belliuiani , s.  renales). 

Until  the  time  of  Ferrein  these  canals,  which  are  visible  to  the  naked 
eye,  were  thought  to  be  simple  : but  it  follows  from  the  researches  of 
this  anatomist  and  those  of  Schumlansky,  that  each  is  a fasciculus  of 
several  hundred  passages,  termed  the  pyramid  of  Ferrein. 

Each  tortuous  canal  is  about  one  sixtieth  of  a line  in  diameter.  The 
total  length  of  all  these  passages  collectively  is,  according  to  Ferrein’s 
estimate,  more  than  sixty  thousand  feet.  There  are  in  each  lobule 
seven  hundred  pyramids,  and  hence  as  each  kidney  is  composed  of 
fifteen  lobules,  there  are  about  ten  thousand  pyramids. 

According  to  Eysenhardt’s  observations,  each  canal  of  the  pyramids 
of  Ferrein  is  composed  of  about  twenty  smaller  ducts.(l) 

But  there  is  certainly  much  incorrectness  and  latitude  in  these  as- 
sertions. 


G.  VESSELS. 

§ 2357.  The  two  series  of  vessels,  after  being  arranged  in  the  fis- 
sure of  the  kidney  in  the  manner  mentioned  above,  enter  into  the  sub- 
stance of  the  organ  on  a level  with  the  base  of  the  renal  papillæ,  and 


(1)  Eysenhardt,  p 12. 


372 


DESCRIPTIVE  ANATOMY. 


go  from  below  upward  in  the  prolongations  sent  inward  by  the  cortical 
substance. 

Their  branches  describe  arches  turned  towards  one  another,  which 
principally  surround  the  bases  of  the  pyramids  of  Ferrein  or  the  dif- 
ferent segments  of  the  inner  substance.  Between  these  arches  the 
anastomoses  are  but  few  and  small.  Although  they  follow  the  divi- 
sions of  the  medullary  substance  they  are  not  distributed  within  it,  but 
almost  exclusively  in  the  cortical  substance,  first  in  the  segments  be- 
tween the  papillæ,  then  in  the  outer  layer  of  the  kidney. 

Numerous  small  branches  radiate  from  the  convexity  of  the  largest  ; 
these  surround  the  base  of  each  lobule,  and  ramify  more  and  more  to 
give  rise  finally  to  glandular  corpuscles.  Many  of  these  branches 
penetrate  to  the  external  face  of  the  kidney  : others  do  not  extend 
so  far. 

The  arteries  and  the  veins  reciprocally  attend  each  other.  Still,  al- 
though the  direct  communication  between  these  two  orders  of  vessels, 
is  admitted  and  is  easily  observed,  we  are  as  yet  unable  to  discover 
any  between  the  most  minute  twigs  of  the  veins  and  the  glandular 
corpuscles,  while  these  latter  adhere  very  intimately  to  the  ramifica- 
tions of  the  arteries,  with  which  they  represent,  as  we  have  already 
mentioned,  a bunch  of  grapes. 

Numerous  lymphatics  arise  from  the  kidneys,  but  these  present  no- 
thing peculiar  in  the  direction  of  their  vessels. 

• H.  NERVES. 

§ 2358.  The  nerves  of  the  kidney  are  proportionally  very  small  ; 
they  arise  from  the  renal  plexus  of  the  great  sympathetic  nerve,  are 
situated  on  the  surface  of  the  arteries,  but  do  not  penetrate  deeply  into 
the  organ. 

II.  URETER. 

§ 2359.  The  ureter(l)  commences  at  the  fissure  of  the  kidney  by 
several  rounded  canals,  the  calices,  which  embrace  the  papillae,  and 
terminate  suddenly  or  rather  become  thinner  rapidly  at  their  bases,  and 
are  continuous  with  their  external  membrane. 

The  number  of  calices  generally  but  not  always  equals  that  of  the 
papillæ.  Sometimes  a calix  divided  only  into  two  compartments  by  a 
slight  .prominence  embraces  two  papillæ,  which  are  then  .near  each 
other,  a structure  which  leads  to  the  union  of  two  of  these  prolonga- 
tions in  one. 

The  others  generally  contract  in  two  large  trunks,  a superior  and 
an  inferior,  which  are  termed  the  branches  of  the  pelvis.  The  superior 


(1)  Pohl,  Obs.  de  ureteribus,  Leipsir,  1772. 


OF  THE  URINARY  SYSTEM. 


373 


trunk  is  generally  larger  and  composed  of  two  branches.  The  two 
trunks  are  united  by  a narrower  intermediate  canal,  which  descends 
longitudinally. 

The  pelvis,  which  gradually  terminates  in  a point  from  above  down- 
ward, on  a level  with  the  lower  extremity  of  the  fissure  of  the  kidney, 
is  as  small  as  the  ureter. 

The  ureter  is  about  two  lines  broad  and  a little  tortuous  ; it  is  sur- 
rounded by  a very  loose  cellular  tissue,  and  descends  on  the  psoas  mus- 
cle behind  the  posterior  wall  of  the  peritoneum.  It  crosses  the  spermatic 
vessels  situated  before  it  and  above  the  primitive  iliac  artery,  to  enter 
into  the  pelvis  : it  then  approaches  that  of  the  opposite  side,  being 
about  an  inch  and  a half  distant  from  it,  and  arrives  at  the  lower  and 
posterior  part  of  the  bladder.  After  proceeding  three  or  four  lines  be- 
tween the  fibres  of  its  muscular  tunic,  forming  a prominence  directed 
from  above  downward  and  from  without  inward,  it  opens  by  an  orifice 
which  is  slightly  narrower,  having  the  same  direction,  but  no  valve. 

§ 2360.  The  ureter  is  formed  of  two  superimposed  layers.  The  ex- 
ternal is  composed  of  a compact  cellular  tissue.  It  has  a fibrous  ap- 
pearance, but  no  muscular  fibres.  The  internal  is  a thin  and  smooth 
mucous  membrane,  which  is  continuous  above  with  that  of  the  renal 
papillæ,  below  with  that  of  the  bladder. 

This  canal  has  no  valves. (1) 

III.  BLADDER. 

§ 2361.  The  bladdçr( 2)  ( vesica  urinaria ) is  an  elongated  rounded 
reservoir,  the  length  of  which  exceeds  its  breadth  and  thickness  ; it  is 
situated  in  the  cavity  of  the  pelvis,  behind  the  symphysis  pubis,  on 
the  outside  of  the  peritoneum,  before  the  rectum  in  the  male  and 
the  vagina  in  the  female,  and  is  surrounded  by  a very  loose  cellular 
tissue.(3) 

(1)  Coschwitz,  De  valvulis  ureterum,  Halle,  1723. 

(2)  J.  Parsons,  Description  of  the  human  urinary  bladder  and  the  parts  belonging 
to  it,  London,  1742. — A.  P.  Walter,  Decolto  vesicœ  virilis , Leipsic,  1745.— J.  Lieutaud, 
Observ.  anat.  sur  la  structure  de  la  vessie;  in  the  Mém.  de  Paris,  1753. — J.  Van 
Beekhoven  de  Wind,  Diss.  de  ureteribus  et  vesicà  urinaria,  Leyden,  1784. 

(3)  As  the  recto-vesical  operation  for  stone,  which  becomes  more  advantageously 
known  every  day,  requires  a very  exact  knowledge  of  the  anatomical  relations  of 
the  bladder,  we  shall  quote  here  the  description  of  it  by  Sanson.  (Des  moyens  de 
parvenir  à la  vessie  par  le  rectum,  Paris,  1817,  p.  15.)  The  base  of  the  bladder  is 
extended  from  behind  forward,  from  the  recto-vesical  layer  of  the  peritoneum  to  the 
origin  of  the  urethra,  is  continuous  on  the  sides  with  the  lateral  regions  of  the  organ, 
although  there  is  no  very  distinct  line  of  demarkation  between  them,  and  its  dimen- 
sions are  nearly  equal  in  every  direction  : it  is  united  by  firm  adhesions  to  the  ureters, 
the  vasa  deferentia  and  the  vesiculæ  séminales,  which  passing  through  it  obliquely 
from  behind  forward  and  from  without  inward,  thus  divide  It  into  three  surfaces, 
two  of  which  are  lateral,  convex,  broader  anteriorly  than  posteriorly,  situated  on  the 
outside  of  the  seminal  vesicles,  and  correspond  to  an  abundant  and  fatty  cellular 
tissue,  which  separates  them  from  the  levatores  ani  muscles,  while  the  third,  the 
central,  exists  between  the  testicles,  is  triangular,  having  a base  which  looks  back- 

Vol.  III.  48 


374 


DESCRIPTIVE  ANATOMY. 


We  distinguish  in  the  bladder  an  upper  and  rounded  part,  termed 
the  base  (fundus),  a central  part,  the  body,  and  an  inferior  part,  the 
neck  ( cervix , s.  collum  vesicœ  urinariœ). 

We  must  regard  it  as  an  excessive  common  dilatation  of  the  ureters, 
which  curves  from  below  upward  on  leaving  the  lower  extremity  of 
these  two  passages. 

It  is  continuous  at  its  lower  extremity  with  the  urethra,  at  the  upper 
with  the  urachus,  a kind  of  ligament  which  proceeds  towards  the  um- 
bilicus along  the  anterior  wall  of  the  anterior  face  of  the  peritoneum, 
gradually  becoming  thinner. 

§ 2362.  The  bladder  is  composed  in  its  whole  extent  of  three  super- 
imposed layers  : but  in  the  upper  part  of  its  posterior  face  there  are 

four. 

The  fourth  layer  is  the  most  external,  and  covers  the  organ  only  in 
the  place  mentioned  ; it  is  the  anterior  part  of  the  inferior  wall  of  the 
peritoneum. 

This  membrane,  which  adheres  to  the  subjacent  muscular  tunic  by 
a very  loose  cellular  tissue,  is  reflected  from  the  bladder  on  the  upper 
part  of  the  anterior  face  of  the  uterus.  The  rest  and  largest  part  of 
the  bladder  is  covered  only  by  a very  loose  layer  of  cellular  tissue, 
which  unites  it  to  the  adjacent  organs. 

ward,  and  corresponds  to  the  peritoneum,  and  a summit  turned  forward,  which 
looks  to  the  prostate  gland  and  rests  directly  on  the  centre  of  the  rectum,  and  follows 
its  curve  exactly  to  the  gland.  It  is  there  separated  from  it,  and  goes  obliquely  from 
behind  forward  and  a little  from  below  upward  to  the  neck  of  the  bladder,  where  if 
blends  with  the  origin  of  the  urethra,  which  may  be  regarded  in  some  measure  as 
its  continuation.  'I  his  latter,  the  origin  of  which  is  embraced  by  the  prostate  gland 
and  blended  with  the  neck  of  the  bladder,  is  not  by  any  means  so  near  the  symphysis 
pubis  as  has  hitherto  been  believed,  since,  placed  upon  a line  which  would  extend 
from  the  lower  part  of  this  symphysis  to  the  summit  of  the  coccyx,  it  is  about  two 
inches  distant  from  it,  first  passes  through  the  prostate  gland,  approaching  the  rec- 
tum a little,  then  becoming  loose  goes  directly  towards  the  root  of  the  penis,  entering 
it  below  the  arch  of  the  pubis,  from  which  it  is  about  fifteen  lines  distant  ; at  the 
same  time  it  is  about  fifteen  lines  distant  from  the  intestine,  with  which  it  forms  an 
angle  open  towards  the  perineum.  The  skin  of  this  region  and  the  prolongation 
of  the  sphincter  downward,  the  urethra  forward,  and  the  last  portion  of  the  rectum 
provided  with  this  same  spliincter  posteriorly,  form  the  three  sides  of  a triangular 
space  filled  by  fatty  cellular  tissue,  the  base  of  which  corresponds  to  the  raphe,  and  at 
the  summit  of  which  is  the  prostate  gland.  If,  taking  the  cavity  of  the  rectum  for 
a point  of  departure,  we  examine  the  parts  before  the  intestine  in  the  order  in  which 
they  appear,  following  the  median  line  of  the  body,  we  find  : 1st,  on  leaving  the 
central  portion,  and  proceeding  obliquely  from  behind  forward  and  from  below  up- 
ward, the  anterior  wall  of  this  portion,  a more  or  less  dense  layer  of  loose  cellular 
tissue  containing  a net-work  of  small  veins,  the  lower  wall  of  the  bladder  and  its 
cavity;  2d,  on  leaving  the  curve  formed  by  the  intestine  below  this  region  to  go 
towards  the  anus,  and  following  a more  horizontal  direction  : the  anterior  wall  of  the 
rectum,  a thin  compact  layer  of  cellular  tissue,  the  prostate  gland  perforated  by  the 
part  of  the  urethra  where  we  remark  the  crest  of  the  urethra  and  the  orifices  of  the 
vasa  deferentia  ; 3d,  finally,  on  leaving  the  lowest  part  of  the  intestine,  and  following 
a horizontal  line  from  before  backward,  the  anterior  wall  of  the  rectum  united  to 
the  sphincter,  the  triangular  space  mentioned  above,  and  entirely  forward,  the  bulb 
of  the  urethra  and  the  posterior  part  of  the  bulbo-cayernosus  muscle.  In  following 
this  direction,  proceeding  from  any  point  whatever,  we  open  no  vessels,  except  the 
capillary  anastomoses  which  establish  the  communication  between  the  two  sides  of 
he  vascular  system.  F.  T. 


OF  THE  URINARY  SYSTEM . 


375 


The  texture  of  the  muscular  membrane  is  very  complex  : it  may, 
however,  generally  be  reduced  to  two  superimposed  layers,  which, 
however,  interlace  at  intervals. 

The  external  layer,  the  strongest  and  most  compact,  is  formed  of 
longitudinal  fibres  ; these  fibres  ascend  from  the  lower  extremity  of 
the  anterior  and  posterior  faces  of  the  bladder  toward  the  base  of  the 
organ,  where  they  partly  anastomose  with  each  other,  and  partly  also 
go  from  within  outward. 

The  posterior  external  fibres  are  reflected  from  above  downward 
some  lines  below  the  urethra,  go  thence  forward  and  upward,  and  are 
then  continuous,  from  without  inward,  with  the  anterior  longitudi- 
nal layer. 

The  lateral  faces  are  mostly  destitute  of  longitudinal  fibres. 

The  internal  layer  is  formed  almost  entirely  of  oblique  fibres  which 
proceed  in  opposite  directions,  so  that  they  frequently  intercross  and 
interlace  together. 

The  inferior  are  entirely  transverse,  and  are  more  compact.  They 
form  the  sphincter  of  the  bladder  (JVf.  sphincter  vesicœ  urinaria ). 

The  others  are  more  remote  from  each  other,  and  represent  a net- 
work, through  the  meshes  of  which  we  observe  the  inner  membranes 
when  the  bladder  is  distended. 

Below  this  second  layer  we  find  in  several  parts,  but  principally 
downward,  some  thinner  muscular  fibres  arranged  longitudinally, 
which  form  in  this  place  a third  layer. 

§ 2363.  Next  to  the  muscular  tunic  come  the  vascular  membrane, 
which  is  very  thin,  and  the  mucous  membrane.  The  latter  is  appa- 
rently smooth,  or  at  least  its  villosities  are  very  minute.  There  are 
generally  no  muciparous  glands  visible  on  its  posterior  face,  except  at 
the  neck  of  the  bladder  ; these  glands,  however,  may  sometimes  be 
seen  when  morbidly  enlarged. 

§ 2364.  The  internal  face  of  the  bladder  is  smooth  in  nearly  its 
whole  extent,  except  some  inconstant  prominences,  which  are  often 
produced  by  the  internal  muscular  layer. 

The  posterior  face  of  the  neck,  however,  presents  an  eminence  which 
leaves  the  orifice  of  each  ureter,  is  directed  downward  and  inward, 
unites  below  at  an  obtuse  angle  with  that  of  the  opposite  side,  on  the 
median  line,  and  thus  gives  rise  to  an  angle  projecting  downward, 
termed  the  trigonus  of  the  bladder  or  of  Lieutaud. 

This  eminence  is  formed  by  some  fasciculi  of  the  internal  muscular 
fibres,  which  are  more  numerous  in  this  part,  the  upper  extremities  of 
which  are  attached  around  the  orifices  of  the  ureters,  and  which  in 
contracting  extend  and  consequently  enlarge  these  orifices,  and  thus 
facilitate  the  flow  of  urine  into  the  bladder.(l) 

• (1)  C.  Bell,  Account  of  the  muscles  of  the  ureters  and  their  effects  in  the  irritable 
state  of  the  bladder  ; in  the  Med.  chir.  Irans.,  vol.  iii.,  p.  171-191. 


376 


DESCRIPTIVE  ANATOMY. 


IV.  URACHUS. 

§ 2365.  The  urachus (1)  is  an  elongated,  very  thin  cord,  which  is 
entirely  enveloped  by  the  peritoneum  ; it  gradually  becomes  thin  from 
below  upward,  is  attached  directly  to  the  anterior  wall  of  the  abdomi- 
nal cavity,  and  goes  from  the  base  of  the  bladder  towards  the  umbi- 
licus, but  frequently  does  not  extend  as  high.  Its  fibres  are  more  or 
less  distinctly  continuous  with  those  of  the  muscular  membrane  of  the 
bladder. 

Its  texture  is  very  differently  stated  by  anatomists.  Their  descrip- 
tions vary,  particularly  as  some  admit  that  it  is  hollow  in  the  adult, 
while  others  deny  it. 

Walter  asserts  it  is  hollow  ;(2)  Noreen,  Senac,(3)  and  Portal,  on 
the  contrary,  think  it  is  full  and  solid. 

The  latter  writers  assert  that  this  cord  is  composed,  beside  its  peri- 
toneal tunic,  of  four  layers,  intimately  united  at  its  upper  part,  that  is, 
in  most  of  its  extent  ; they  separate  near  the  summit  of  the  bladder, 
and  in  passing  under  its  muscular  membrane,  go,  two  on  the  sides, 
the  other  two  on  the  anterior  and  posterior  faces  of  the  bladder  to 
its  neck.  They  add  that  these  two  layers  unite  with  each  other 
and  with  the  peritoneal  coat  more  intimately  as  age  advances. 

Walter,  on  the  contrary,  states  the  urachus  to  be  formed  externally 
by  longitudinal  and  then  by  circular  fibres,  and  after  that  by  the  vas- 
cular and  muscular  membranes  of  the  bladder.  We  may  introduce 
into  it  for  some  inches  a sound  and  mercury,  but  it  terminates  at 
the  side  of  the  umbilicus  in  a cul-de-sac,  and  often  contains  a reddish 
fluid. 

From  our  observations  it  follows  that  generally  the  urachus  is  com- 
pletely obliterated  when  the  body  is  perfectly  developed,  and  often 
even  long  before  this  period,  and  thus  it  is  then  changed  into  a per- 
fectly homogeneous  cord,  although  we  have  often  seen  the  arrange- 
ment mentioned  by  Walter. 

Finally,  Noreen  and  Portal  themselves  mention  several  instances  of 
this  structure,  which  Noreen  has  figured  very  exactly. 

(1)  J.  C.  Peyer,  Observât,  circa  urachum,  Leyden,  1721. — J.  Noreen,  De  mutatione 
luminum  in  vasis  hominis  nascentis , in  specie  de  uracho,  Gottingen,  1749. — P.  A. 
Bœhmer,  De  uracho  in  adulto  homine  aperto , cum  cjusd.  anat.  ovi  hum.,  Halle,  1765. 
— A.  Portal,  Sur  la  structure  et  sur  l'usage  de  Vouraque  dans  l'homme  ; in  the  Mém. 
de  Paris,  1769,  p.  19. 

(2)  Obs.  anat.,  Berlin,  1775,  p.  19. 

(3)  Essais  de  physique  ; in  Portai,  Mém.  sur  phis,  maladies,  vol.  i. 


OF  THE  URINARY  SYSTEM. 


377 


V.  URETHRA. 

§ 2366.  The  urethra, { 1)  the  termination  of  the  urinary  system,  is  a 
canal  narrow  in  proportion  to  the  bladder,  which  is  continuous  by  its 
inner  extremity,  the  vesical  orifice,  with  the  neck  of  the  bladder,  and  by 
its  outer  extremity,  the  cutaneous  orifice,  with  the  common  integu- 
ments. It  is  composed  in  both  sexes  of  a mucous  membrane  covered 
with  a loose  and  spungy  cellular  tissue,  and  a very  complex  vascular 
net-work.  It  is  much  shorter  in  the  female  than  in  the  male,  being 
about  two  inches  long  in  the  former  and  eight  in  the  latter.  The 
urethra  in  the  female,  on  the  contrary,  is  much  broader  than  in  the 
male. 

In  both  sexes  this  canal  is  situated  below  the  organs  of  pleasure, 
that  is,  in  the  female  below  the  clitoris,  and  in  the  male  below  the 
corpus  cavernosum  of  the  penis,  which  latter  it  contributes  to  form. 

From  the  different  length  of  these  parts  it  does  not  open  at  the  same 
place  in  the  two  sexes.  In  fact  in  females  its  external  orifice  is  situated 
directly  before  the  entrance  of  the  vagina,  and  between  the  external 
labia  ; in  males  at  the  anterior  extremity  of  the  penis.  As  in  the  male 
it  is  also  the  excretory  canal  of  the  semen,  it  will  be  more  convenient 
to  describe  its  texture  when  treating  of  the  genital  organs. 

B.  FUNCTIONS  OF  THE  URINARY  ORGANS. 

§ 2367.  The  function  of  the  urinary  organs  is  to  secrete  and  to 
excrete  the  urine  {urina,  lotium). 

The  physical  qualities  of  this  liquid  are  its  yellowness,  tenuity, 
transparence,  slight  viscosity,  and  particularly  its  peculiar  odor. 

The  urine  is  composed  of  numerous  constituent  parts,  which  vary 
more  in  their  proportions  than  number  and  nature,  at  different  periods, 
than  in  any  other  animal  liquid. 

One  of  the  principal  characters  of  its  chemical  composition  consists 
in  the  great  quantity  of  water  it  contains,  which  forms  at  least  nine 
tenths  of  it. 

The  substances  which  in  the  normal  state  are  always  or  most  ge- 
nerally dissolved  in  the  water,  are  : 

1st.  Urea,  which  of  all  the  animal  substances  possesses  the  most 
azote,  as  it  contains  thirty-two  per  cent,  according  to  Fourcroy  and 
Vauquelin  ; forty-three  per  cent,  according  to  Berard  ; and  even  forty- 

(1)  A.  Moreschi,  Commentarium  de  urethrce  corporis  glandisque  structura , Milan, 
1817.— Amussat,  Remarques  sur  l’urèthre  de  l'homme  et  de  la  femme  ; in  the  Archiv, 
gên.  de  méd.,  vol.  iv.,  p.  31  and  547. — E.  Home,  Mém.  sur  la  structure  de  l’urèthre, 
d’après  les  observations  microscopiques  ; same  journal,  vol.  ii.,  p.  140. — T.  Ducamp, 
Traité  des  rétentions  d’urine,  Paris,  1822,  p.  1. 


378 


DESCRIPTIVE  ANATOMY. 


six  per  cent,  according  to  Prout,  while  there  is  only  about  twenty  per 
cent,  in  the  fibrine. 

2d.  An  animal  substance  insoluble  in  alcohol. 

3d.  Several  acids,  the  uric(l)  and  the  lactic. 

4th.  Several  salts,  viz.  the  lactate  of  ammonia,  sulphate  of  potash, 
sulphate  of  soda,  phosphate  of  soda,  hydrochlorate  of  ammonia,  and 
the  earthy  phosphates,  with  some  fluate  of  lime. 

5th.  A little  of  silex. (2) 

Besides  these  substances,  which  enter  regularly  into  the  urine,  we 
sometimes  recognize  by  our  senses  several  constituent  principles  of  the 
body  introduced  into  the  system  in  different  modes.  Thus,  for  in- 
stance, rhubarb  colors  it  a deep  yellow,  and  asparagus  communicates 
to  it  a disagreeble  odor. 

Although  these  substances  also  occur  in  greater  or  less  quantity  in 
the  other  excretory  fluids,  especially  in  those  exhaled  by  the  lungs 
and  the  skin,  and  in  the  matters  expelled  directly  from  the  intestinal 
canal,  they  nevertheless  occur  more  frequently  in  the  urine,  so  that 
the  urinary  system  seems  to  be  the  principal  excretory  organ  of  those 
materials  which  cannot  be  assimilated.  It  necessarily  exercises  a pe- 
culiar attraction  for  these  substances,  in  order  to  remove  them  from  the 
blood  and  fulfil  its  function. 

This  system  is  also  the  principal  agent  of  purifying  it  in  the  morbid 
state  : thus  the  urine  is  more  or  less  modified  in  all  diseases  generally. 

§ 2368.  But  the  urine  constantly  presents  differences  also  in  regard 
to  the  greater  or  less  length  of  time  which  has  elapsed  between  its 
emission  and  taking  food  or  drink.  Upon  this  is  founded  the  distinc- 
tion between  the  urine  of  ihe  drink,  and  the  urine  of  digestion  or  of 
the  blood.  But  it  must  be  admitted  that  these  differences  are  very 
slight. 

The  urine  of  the  drink,  which  is  voided  directly  after  a meal,  is  very 
watery  and  limpid.  The  urine  of  digestion,  voided  some  hours  after 
eating,  during  the  digestive  process,  is  more  colored,  less  watery,  more 
odorous,  and  usually  presents  the  smell  and  taste  of  some  of  the  articles 
of  food.  Finally,  that  which  is  passed  when  digestion  is  finished,  the 
proper  and  perfect  urine,  is  more  highly  colored,  and  less  in  quantity  : 
it  has  not  the  characters  of  the  ingesta,  but  on  the  contrary,  presents 
the  characteristic  smell  and  taste  of  the  urine. 

From  comparative  experiments,  the  urine  of  the  food  contains  only 
one  thirteenth  of  urea,  one  sixteenth  of  uric  acid,  and  one  fourth  of  the 
salts  found  in  the  urine  of  digestion  or  of  the  blood. 

<5  2469.  For  a long  time  the  question  has  been  discussed,  and  it  is 
not  yet  settled,  whether  the  constituent  materials  of  the  urine  are 


(1)  It  seems  probable,  from  Prout’s  experiments,  that  pure  uric  acid  does  not  exist 

in  the  urine,  but  it  is  combined  with  ammonia.  Lactic  acid  is  then  the  only  cause 
of  the  acidity  of  the  urine  in  the  normal  state.  k T. 

(2)  Berzelius,  Annales  de  chimie,  vol.  lxxxix.,  p.  22. 


OF  THE  URINARY  SYSTEM. 


379 


carried  to  the  urinary  system  only  by  the  vascular  system,  or  whether 
they  do  not  proceed  there  directly  by  a shorter  route,  and  consequently, 
whether  there  are  not  secret  urinary  passages  ( vice  urinaria  clandes- 
tina). 

The  arguments  in  favor  of  the  existence  of  these  passages,  are  :(1) 

1st.  The  rapidity  with  which  fluids,  especially  cold  water,  are 
expelled  with  the  urine,  and  particularly  the  great  quantity  of  fluids 
evacuated  in  a short  time  through  this  passage,  whether  these  liquids 
have  been  introduced  into  the  intestinal  canal,  or  injected  into  the  cavity 
of  the  abdomen. 

2d.  The  passage  of  several  substances  through  the  urine  unchanged, 
instances  of  which  we  mentioned  above. 

3d.  The  presence  in  the  urine  or  in  the  lymphatic  vessels  between 
the  mesentery  and  the  urinary  system,  of  these  substances,  or  of  other 
materials  formed  even  in  the  body,  as  the  saccharine  matter  in  diabetes, 
although  the  blood  contains  no  trace  of  them. 

4th.  The  presence  of  urine  in  the  bladder,  although  the  kidneys 
have  been  destroyed,  the  ureters  tied,  and  even  when  the  kidneys  did 
not  exist,  or  at  least  they  did  not  communicate  with  the  ureters. 

5th.  The  presence  in  the  bladder  of  solid  bodies  introduced  into  the 
body  by  swallowing  or  any  other  mode. 

6th.  The  very  active  sympathy  between  the  bladder  and  the 
stomach. 

The  manner  in  which  the  substances  contained  in  the  urine  can  ar- 
rive at  the  urinary  system  without  passing  through  the  vessels,  has 
been  explained  in  several  different  ways. 

1st.  Some  think  there  are  no  visible  channels, but  that  the  phenomena 
depend  simply  on  transudation  through  the  adjacent  parts,  particularly 
from  the  intestinal  canal  into  the  bladder,  through  the  medium  of  the 
mucous  tissue. (2) 

2d.  Others  admit  a retrograde  motion  in  the  lymphatic  vessels  and 
urinary  system,  and  even  support  their  opinion  by  those  cases  where 
the  valves  of  these  vessels  have  an  opposite  direction,  and  are  turned 
from  the  heart. 

3d.  Finally,  some  admit  special  canals,  situated  between  the  sto- 
mach and  the  urinary  apparatus. 

§ 2370.  But  it  is  easy  to  refute  all  these  arguments  and  the  man- 
ner in  which  they  are  explained. (3) 


(1)  C.  G.  Kratzenstein,  Theoria  ßuxus  diabetici  ejusque  sanandi  methodus , 
Halle,  1746. — Darwin,  Zoonomie,  vol.  i. — -Wollaston,  in  the  Phil,  trans.  1811. — Tre- 
viranus,  Biologie , vol.  iv.  p.  513-521. — Morichini,  in  the  Mem.  della  soc.  Hal.,  vol. 
xvii.-Tiedemann  and  Grnelin,  Recherches  sur  la  route  que  prennent  diverses  substan- 
ces pour  passer  de  l'estomac  el  du,  canal  intestinal  dans  le  sang,  sur  la  fonction  de  la 
rate  et  sur  les  voies  cachées  de  l'urine , Paris,  1821. 

(2)  Treviranus,  Biologie , vol.  iv.  p.  513-521. 

(3)  P.  J.  Hartmenn,  Super  urinæ  diâpedes  quœstiones,  Utrecht,  1776. — G.  G. 
Erhardt,  De  secrelione  lotiiunica  et  svfjicientc,  Erfort,  1799. — J.  Jacopi,  Esame  della 
doclrina  di  Darwin  sulmoio  rclrogrado  dciliquidincivasi  Zûi/att'd,  Pavia,  1804. 


330 


DESCRIPTIVE  ANATOMY. 


Nothing  can  be  concluded  from  the  last  two  arguments,  for  the  sym- 
pathy between  the  stomach  and  the  urinary  system  does  not  depend 
on  mechanical  connections  between  them,  and  solid  bodies  penetrate 
through  unusual  channels  formed  by  these  bodies  from  the  compres- 
sion they  exercise. 

In  order  to  refute  the  fourth  argument,  it  is  sufficient  to  remark  that 
we  do  not  in  fact  find  urine  in  the  bladder  when  the  kidneys  have  been 
entirely  destroyed,  that  a portion  of  the  kidney  still  remains  where 
they  seem  to  have  been  entirely  destroyed,  that  no  urine  collects  in  the 
bladder  after  tying  the  ureters,  if  the  bladder  be  entirely  emptied  ; and 
finally,  that  the  cases  of  a noncommunication  between  the  ureters  and 
the  kidneys  are  very  doubtful. 

To  the  third  argument  we  may  answer,  that  at  least  all  the  imme- 
diate principles  of  the  animal  substances  do  not  exist  in  the  blood  ; 
those  found  there  do  not  exactly  resemble  those  in  the  body,  since  the 
same  substances  occur  in  other  parts  of  the  body,  from  whence  it  is 
not  proved  that  they  pass  into  the  urinary  system  : that  very  possibly 
the  substances  proved  to  exist  in  the  urine,  might  have  disappeared  from 
the  blood  or  were  concealed  in  some  mode  : that  these  substances  have 
not  been  looked  for  in  the  arterial,  but  in  the  venous  blood  : finally, 
that  according  to  Magendie,  we  may  prove  the  existence  of  one  of 
these  substances,  the  hydrocyanate  of  potass,  in  the  urine,  in  any 
quantity  however  small,  while  after  mixing  it  with  the  blood,  even  out 
of  the  body,  we  cannot  detect  it,  even  when  in  great  quantity,  by 
chemical  reagents. 

Besides  the  simultaneous  existence  of  several  substances,  as  rhubarb, 
has  been  proved  in  the  serum  ofithe  blood  and  the  urine.(l) 

Treviranus  asserts(2)  that  this  phenomenon  proves  nothing,  as  the 
serum  of  the  blood  contained  less  rhubarb  than  the  urine.  But  it  is 
easy  to  refute  this  objection,  as  the  rhubarb  is  distributed  through  the 
whole  mass  of  the  serum,  and  could  only  be  removed  from  it  by  the 
urinary  system. 

The  lymphatic  vessels,  situated  near  the  mesentery,  may  either 
have  sent  these  substances  into  the  urinary  system,  and  have  accident- 
ally imparted  to  them  a retrograde  motion,  contrary  to  that  which  the 
fluids  generally  follow,  although  we  have  no  right  to  conclude  that 
foreign  substances  always  enter  the  urinary  system  through  this  chan- 
nel, nor  even  by  admitting  the  retrogade  motion,  that  they  were  intro- 
duced by  it. 

The  facts  alledged  in  support  of  the  second  argument,  do  not  con- 
tribute in  manner  to  the  explanation  given  of  them.  The  formation 
and  the  want  of  decomposition  in  certain  substances  would  not  be  ex- 
plained more  easily  by  this  theory  : for  even  admitting  this  channel, 
which  is  not  much  shorter,  they  are  no  less  subject  to  the  organic 
action  : but  Davy’s  observations  prove,  that  under  the  influence  of 

(1)  Home,  in  the  Phil.  Irans.,  1808. 

(2)  Biologic , vol.  iv.  p.  520. 


or  THE  URINARY  SYSTEM. 


381 


electricity,  bodies  may  be  separated  contrary  to  the  laws  of  chemical 
affinity,  and  earned  far  by  the  fluids,  without  combining  with  other 
substances  which  these  fluids  contain,  and  which  have  great  affinity 
for  them. 

Finally,  in  regard  to  the  first  argument,  the  rapidity  with  which 
drinks  and  certain  substances  pass  into  the  urinary  system,  is  not  in 
fact  as  great  as  has  been  asserted,  and  may  be  easily  explained  by  the 
short  distance  they  proceed,  even  admitting  that  they  are  carried  there 
by  the  blood. 

If  we  find  rhubarb  in  the  urine  in  seventeen  minutes,  if  it  disap- 
pears from  this  liquid  at  the  end  of  some  hours,  if  it  colors  the  excre- 
ment after  six  or  seven  hours,  and  is  then  found  again  in  the  urine, 
this  fact  does  not  prove  as  Treviranus  asserts/ 1)  that  the  rhubarb 
first  found,  has  arrived  at  the  urinary  system  by  a shorter  route  than 
that  afterward  observed. 

The  rhubarb  which  appears  first  in  the  urine,  has  undoubtedly 
passed  from  the  stomach,  to  the  inner  and  absorbing  face  of  which  it 
was  presented,  without  being  decomposed  into  the  sanguineous  system, 
and  seventeen  minutes  is  not  too.  short  for  the  latter  to  come  to  the 
urinary  system.  The  action  of  the  rhubarb  on  the  inner  face  of  the 
stomach  and  intestinal  canal,  gradually  causes  the  mucous  membrane 
of  these  organs  to  a greater  secretion,  which  surrounds  them  on  every 
part  and  diminishes  absorption.  When  this  excessive  action  abates, 
the  rhubarb  is  again  absorbed.  But  there  is  another  cause  to  which 
we  must  probably  attribute  the  disappearance  of  the  rhubarb  in  the 
urine  during  a certain  length  of  time,  viz.  that  the  action  of  the  kid- 
neys is  l.ess  energetic,  while  that  of  the  alimentary  canal  is  increased. 

§ 2371.  In  regard  to  the  passages,  we  may  say  : 

1st.  The  opinion  that  the  cellular  tissue  serves  as  a conductor,  is 
very  improbable,  first,  because  the  application  of  phenomena  observed 
in  the  inferior  animals,  to  the  theory  of  those  which  occur  in  the  su- 
perior animals,  leads  only  to  uncertain  results,  since  by  admitting  this 
supposition,  it  is  difficult  to  explain  why  the  passage  takes  place 
through  the  kidneys. 

2d.  The  retrograde  motion  in  the  lymphatic  vessels  is  very  impro- 
bable, at  least  in  the  normal  state,  on  account  of  the  existence  of  valves. 
The  cases  where  it  is  asserted  the  valves  were  found  arranged  con- 
trary to  what  they  are  generally,  are  only  exceptions,  or  at  least  are 
not  sufficiently  proved.  Farther,  this  arrangement  could  not  be  gene- 
ral, since  then  there  could  be  no  absorption  from  the  bladder.  It  is  not 
proved  that  these  valves  are  arranged  in  one  manner  in  certain  lym- 
phatics, and  an  opposite  manner  in  others. 

3d.  The  special  canals  have  never  been  proved  by  authentic  obser- 
vations, and  the  passages  considered  as  such,  were  evidently  acciden- 
tal and  morbid  formations. 

(1)  Biologie , vol.  iv.  p.  519. 


Voi.  III. 


49 


382 


DESCRIPTIVE  ANATOMY". 


4th.  Finally,  another  circumstance  prevents  its  admission,  viz.,  that 
we  have  never  found  between  the  digestive  canal  and  the  urinary  pas- 
sages,  any  substance  in  these  two  systems  not  contanied  in  the  san- 
guineous system,  and  even  when  this  phenomenon  occurs,  it  can  al- 
ways be  explained  by  saying  that  the  substances  in  this  place,  especi- 
ally in  the  lymphatic  vessels,  have  come  there  from  the  urinary 
system. 


C.  SEXUAL  DIFFERENCES. 

§ 2372.  The  urinary  system,  except  the  bladder  and  the  urethra, 
presents  no  considerable  differences  relative  to  sex. 

The  bladder  is  rounder,  broader,  and  generally  larger  in  the  female 
than  in  the  male,  where  it  is  more  elongated. 

The  urethra  of  the  female  is  broader  and  shorter  than  that  of  the 
male,  representing  in  fact  only  its  commencement. 

D.  DIFFERENCES  DEPENDENT  ON  DEVELOPMENT. 

§ 2373.  This  system  changes  much  during  life,  in  form,  texture, 
proportional  size,  and  situation. 

I.  KIDNEYS. 

§ 2374.  1st.  The  kidneys  are  much  larger  proportionally  the  younger 
the  fetus  is  : in  the  full-grown  fetus  their  weight  is  to  that  of  the  whole 
body  as  1 : 80,  while  the  proportion  in  the  adult  is  as  1 : 240. 

2d.  In  respect  to  form  they  are  more  elongated,  and  the  pelvis  is 
nearer  the  anterior  face,  so  that  the  renal  fissure  is  less  developed. 
Their  surface  is  not  smooth  ; they  do  not  form  a coherent  and  homo- 
geneous mass,  but  are  composed  of  several  lobules,  which  are  at  first 
distinct,  but  are  united  so  as  to  produce  the  larger  lobes,  which  are  very 
evident  in  the  adult,  where,  however,  they  are  not  separated.  At  this 
period  of  life,  in  fact,  they  are  attached  only  by  a very  loose  cellular 
tissue,  so  that  they  are  easily  insulated,  and  their  bases  are  even 
marked  on  the  surface  of  the  kidney  by  considerable  depressions. 

3d.  The  medullary  substance  is  more  abundant  in  proportion  to  the 
cortical  substance,  than  in  the  adult,  at  least  in  the  full  grown  fetus. 
The  fasciculi  of  the  urinary  passages,  or  the  pyramids  of  Ferrein,  are 
separated  from  one  another  more  easily,  and  like  all  parts  of  the  body, 
are  evidently  composed  of  globules,  which  are  not  seen  in  the  adult  ; 
on  the  contrary,  the  passages  are  more  difficult  to  be  distinguished. 
Here  then,  also,  as  in  the  muscles  and  the  lungs,  the  large  parts  are 
formed  before  the  small. 


OF  THE  URINARY  SYSTEM. 


283 


II.  URETERS. 

§ 2375.  The  ureters  are  also  broader,  proportionally,  than  when  the 
subject  is  perfectly  developed. 

III.  BLADDER. 

§ 2376.  From  the  narrowness  of  the  pelvis,  the  bladder  is  not  con- 
tained in  this  cavity  ; it  is  then  situated  much  higher  than  in  the  adult, 
so  that  the  urethra  is  proportionally  very  much  longer. 

It  is  much  smaller  before  than  after  birth. 

Its  form  is  more  elongated.  This  circumstance  and  its  smallness, 
cause  it  to  appear  as  a simple  filament,  and  it  seems  to  be  only  a slight 
dilatation  of  the  urachus. 


IV.  URACHUS. 

§ 2377.  The  urachus  is  much  larger  the  younger  the  person  is  ; it 
gradually  diminishes,  until  in  the  course  of  life  it  often  entirely  disap- 
pears. 

It  is  at  first  hollow,  and  according  to  our  observations,  it  retains  this 
character  in  the  full-grown  fetus.  At  this  period  we  can  distinguish 
in  it  all  the  constituent  membranes  of  the  bladder  with  which  its  cavity 
communicates.  This  cavity  is  at  first  much  larger  proportionally,  the 
younger  the  fetus  is.  In  the  full-grown  fetus,  and  still  more  at  the 
periods  preceding  birth,  we  can  follow  the  urachus  a greater  or  less 
distance,  but  always  several  inches  beyond  the  opening  of  the  umbili- 
cus, sometimes  even  the  whole  extent  of  the  cord.  Analogjr  with  ani- 
mals, and  several  observations  upon  man,  authorize  us  to  think  that  it 
passes  at  first  entirely  through  the  umbilical  cord,  and  dilates  between 
the  envelops  of  the  fetus,  to  give  origin  to  a membranous  vesicle,  the 
allantosi , to  which  we  shall  return  when  describing  the  human  ovum. 
This  cord  is  certainly  hollow,  for  even  in  the  full-grown  fetus  we  have 
injected  it  with  mercury  through  the  bladder,  and  the  injection  extended 
more  or  less  in  the  umbilical  cord.  Our  observations  on  this  subject 
agree  with  those  of  Rcederer(l)  and  Noreen.(2) 

Several  of  the  ancient  anatomists,  and  even  Trew,  among  the  mo- 
derns,(3)  have  admitted  that  the  urachus  is  full  and  solid  in  the  fetus, 
as  it  normally  is  in  the  adult.  This  erroneous  opinion  depends 
upon  a great  inflexion  in  the  canal  near  its  lower  extremity  ; hence, 
when  the  bladder  is  distended,  the  muscular  fibres  are  so  adapted  to 
its  sides,  that  the  opening  by  which  they  communicate  is  closed. 

(1)  De fœtuperfecto , Halle,  1759. 

(2)  hoc.  cit.,  p.  13. 

(3)  De  cliff,  inter,  hom.  natum  et  nascendum,  p.  104. 


3S4 


DESCRIPTIVE  ANATOMY. 


ARTICLE  SECOND. 

URINARY  SYSTEM  IN  THE  ABNORMAL  STATE. 

§ 2378.  The  urinary  system  is  one  of  those  anomalies  which  occur 
most  frequently,(l)  particularly  as  respects  those  of  formation,  for  the 
most  striking  differences  it  presents,  relate  to  the  form,  situation,  and 
size  of  its  different  component  parts,  and  also  to  its  vessels.  Besides, 
its  cavity  not  unfrequently  includes  foreign  bodies,  which  depend  par- 
ticularly on  alterations  in  the  chemical  composition  of  the  urine. 


DEVIATIONS  OF  FORMATION. 

A.  KIDNEYS. 

§ 2379.  The  primitive  deviations  of  formation  in  the  kidneys, (2) 
which  depend  more  or  less  evidently  on  a suspension  of  development, (3) 
are  : 

1st.  The  absence  of  one  or  both  of  them. 

2d.  Smallness , in  which  case  when  this  anomaly  occurs  on  one  side 
only  it  is  frequently,  but  not  always,  made  up  by  the  greater  size  of 
the  kidney  of  the  other  side. 

3d.  The  greater  or  less  difference  in  the  size  of  the  two  kidneys. 

4th.  The  great  size  of  these  two  organs. 

5th.  Their  union  in  one  only.  This  anomaly  differs  much  in  degree 
and  quality. 

The  differences  in  respect  to  quality  principally  affect  their  situation. 
Sometimes  there  is  no  trace  indicating  that  a kidney  has  ever  existed 
in  the  place  where  it  is  not  found  ; the  single  kidney  occupies  the 
usual  place,  follows  the  normal  direction,  and  we  discover  that  it  is 
formed  by  the  union  of  the  two,  not  only  because  it  is  larger  than  in 
the  normal  state,  but  also  because  it  is  contracted  at  its  centre,  from 
the  excess  in  the  number  of  its  vessels,  its  fissure,  pelvis,  and  ureter. 
Sometimes  the  two  halves  of  the  single  kidney  are  situated  each  in 
the  usual  place. 

As  to  the  differences  in  degree,  the  two  kidneys  are  generally  united 
only  at  their  lower  part  and  to  a greater  or  less  extent,  so  that  they 

(1)  Baillie,  Engravings,  London,  812,  fasc.  vi-viii. — C.  Bell,  Engravings  from 
specimens  of  morbid  parts,  preserved  in  the  authors  collection  selected  from  the  divi- 
sion inscribed  urethra , vesica,  renés , morbosa  et  lœsa,  &c.  London,  1813. — J.  How- 
ship,  Practical  observations  on  the  diseases  of  the  urinary  organs , particularly  those 
of  the  bladder , prostate,  gland,  and  urethra,  London,  1816. 

(2)  O.  Heer,  De  renum  morbis,  Halle,  1790. 

(3)  See  in  respect  to  these  deviations  of  formation,  our  Handbuch  der  patholo- 
gischen Anatomie,  vol.  i.  p.  610. 


OF  THE  URINARY  SYSTEM. 


385 


form  a semicircular  mass,  which  is  concave  upward  and  convex  down- 
ward. The  union  extends  more  rarely  to  their  whole  height,  in  which 
case  they  are  changed  into  a rounded  or  square  mass. 

6th.  They  are  more  oblong  than  usual. 

7th.  The  situation  of  the  pelvis  on  the  anterior  face.  These  two 
anomalies  generally  attend  enlargement,  but  they  sometimes  occur 
also  although  there  is  no  mark  of  hypertrophy. 

8th.  The  lobular  structure,  which  sometimes  gives  rise  to  several 
separate  kidneys. 

Their  low  situation,  so  that  sometimes  we  find  the  two  kidneys  in 
the  pelvis. 

§ 2380.  Several  of  these  anomalies  are  developed  also  during  life 
only,  as  is  true  of  abnormal  enlargement  and  diminution.  Not  unfre- 
quently,  in  fact,  the  kidneys  enlarge  sometimes  to  an  enormous  extent, 
although  they  change  their  texture,  or  on  the  contrary  they  disappear 
and  are  almost  entirely  effaced. 

In  the  latter  case  sometimes  they  diminish  much  in  volume,  but 
their  mass  continues  solid,  or  they  even  preserve  their  size  or  enlarge, 
but  their  substance  is  almost  wholly  destroyed,  and  they  are  changed 
into  a sac  with  thin  parietes.  Wasting  of  the  first  kind  supervenes 
after  a disease  of  the  organ  ; but  not  so  with  the  second,  which  often 
depends  on  an  obstacle  to  the  escape  of  the  urine  which  exists  below 
îhe  kidneys. 

B.  URETERS. 

§ 2381.  The  deviations  in  the'  form  of  the  ureter  are  particularly 
worthy  of  notice. 

Their  congenital  anomalies  are  : 

1st.  Their  absence. 

2d.  Their  imperforation  in  one  or  several  points,  from  an  obstacle. 

3d.  Their  plurality , occurring  from  the  want  of  union  of  the  branches 
of  the  pelvis  ; this  exists  in  different  degrees.(l) 

The  most  common  consecutive- deviation  of  formation  is  their  ab- 
normal dilatation  or  distension  from  an  obstacle  to  the  course  of  the 
urine  situated  in  the  ureter,  or  in  another  portion  of  the  urinary  system, 
or  even  out  of  it.  Obstacles  of  the  first  kind  are  calculi  and  contrac- 
tions ; those  of  the  second  are  the  engorgement  of  the  glands  of  the 
pelvis,  the  swelling  of  the  internal  genital  organs,  the  adhesions  of 
these  parts  either  with  each  other  or  with  the  adjacent  organs,  &c. 

Finally,  the  ureter  is  sometimes  ruptured  from  excessive  distension. 


(1)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  i.,  p.  715. 


386 


DESCRIPTIVE  ANATOMY. 


C.  BE  ADDER. 

§ 2382.  The  primitive  deviations  iji  the  form  of  the  bladder  are  : 

1st.  Its  absence , attended  or  not  with  that  of  the  rest  of  the  urinary 
system. 

2d.  Its  smallness. 

3d.  Its  fissure.  This  anomaly  is  not  very  rare,  and  is  termed  the 
prolapsus  of  the  bladder ( 1)  ( prolapsus  vcsicœ  urinariœ  inversa).  Its 
principal  characters  are  : 

At  the  lower  extremity  of  the  anterior  face  of  the  abdomen,  above 
the  symphysis  pubis,  is  a reddish,  soft,  rounded  place,  the  edges  of 
which  are  continuous  with  the  common  integuments,  and  at  the  base 
of  which  are  two  mammillary  eminences  directed  one  towards  the 
other,  whence  urine  continually  dribbles.  It  is  the  bladder  in  the  form 
not  of  a pouch  but  a layer,  the  anterior  face  of  which  is  formed  by  its 
mucous  membrane. 

Behind  this  membrane  is  the  muscular  tunic,  covered  at  its  upper 
part  by  the  peritoneum.  The  eminences  are  the  orifices  of  the  ureters 
situated  in  the  usual  place,  and  which  are  not  generally  abnormal, 
except  from  their  great  breadth. 

The  umbilicus  is  situated  directly  above  the  upper  extremity  of  the 
bladder,  and  consequently  much  lower  than  usual. 

The  urethra  then  most  generally  opens  above  the  penis  in  the  male, 
and  the  clitoris  in  the  female  : it  is  more  or  less  cleft,  and  more  or  less 
imperfectly  developed.  Considered  generally,  the  external  genital 
organs  seem  to  have  separated  from  each  other  to  the  right  and  left. 

Excepting  at  most  two  cases  as  yet  published,  the  symphysis  pubis 
is  always  more  or  less  imperfectly  closed,  on  which  depends  the  appa- 
rent shortness  of  the  penis. 

Duncan(2)  asserts  that  this  anomaly  belongs  particularly  to  males  : 
but  the  number  of  cases  of  its  occurrence  in  females,  mentioned  by  this 
author,  may  be  much  enlarged. 

4th.  The  bifurcation  of  the  bladder,  or  its  formation  by  several  con- 
nected sacs.  (3) 

5th.  The  continuance  of  the  urachus  to  the  umbilicus,  through 
which  the  urine  then  escapes. 

§ 2383.  The  following  anomalies  are,  at  least  commonly,  consecu- 
tive or  accidental. 

1st.  Excessive  size.  Here  there  is  sometimes  simple  dilatation,  and 
sometimes  an  increase  in  mass  and  volume.  This  anomaly  generally 
depends  on  an  obstacle  to  the  course  of  the  urine,  situated  at  the  lower 
part  of  the  bladder  or  in  the  urethra. 

(1)  Meckel,  loc.  cit. 

(2)  Edinb.  med.  and  sur g.  journal,  1806. 

(3)  J.  A.  Ehrlich,  Chirurgische  Beobachtungen,  vol.  ii.,  Leipsic,  1815,  p.  123. 


or  THE  URINARY  SYSTEM. 


387 


2d.  The  considerable  development  of  the  muscular  tunic,  which 
sometimes  occurs  without  dilatation,  or  even  when  the  bladder  is. 
unusually  small,  which  depends  particularly  on  the  presence  of  a 
foreign  body,  as  a calculus,  in  the  bladder. 

3d.  Hernias  of  the  inner  membrane  of  the  bladder  through  the  mus- 
cular tunic  ( appendices , s.  processus),(l)  which  are  very  rarely  conge- 
nital, and  commonly  arise  from  the  same  cause  as  the  preceding. 

4th.  Ruptures  of  the  bladder,  which  are  generally  caused  by  its 
excessive  distension. 

5th.  Displacements , hernias  of  the  bladder.  The  bladder  most  ge- 
nerally projects  at  the  base,  and  gives  rise  to  vaginal  hernia  when  it 
rests  on  the  vagina,  either  because  it  has  become  very  heavy,  as  in 
the  cases  where  it  is  filled  by  a calculus,  or  because  it  is  depressed  by 
the  contraction  of  the  space  it  occupies,  as  in  pregnancy.  It  then 
causes  a more  or  less  perfect  inversion  of  the  vagina,  after  which  it  is 
itself  precipitated  more  or  less,  especially  when  the  inversion  is  conge- 
nital. 

We  also  find  the  bladder  in  inguinal  hernias,  but  much  more 
rarely.(2) 

6th.  When  the  bladder  and  vagina  fall  rapidly,  there  is  sometimes 
an  inversion  of  the  bladder.  The  urethra  is  necessarily  more  or  less 
torn,  in  order  that  this  accident  should  supervene. 


II.  ALTERATIONS  OF  TEXTURE. 

A.  KIDNEYS. 

§ 2384.  The  two  kidneys  do  not  always  possess  the  same  consist- 
ence. They  are  sometimes  very  flabby  in  persons  affected  with  dia- 
betes, in  which  case  they  frequently  receive  more  blood  than  usual. 

On  the  other  hand  they  are  sometimes  unusually  firm. 

They  are  not  unfrequently  changed  into  fat. 

Frequently  also  a great  number  of  serous  cysts  are  developed  in 
these  glands  in  old  persons  ; these  generally  adhere,  are  filled  with  a 
differently  colored  and  generally  a limpid  serum,  which  sometimes  en- 
tirely destroys  their  substance.  In  some  cases  the  kidney  seems 
formed  primitively  of  similar  cysts. (3) 

Scrofulous(4)  and  spungy  tumors  occur  more  rarely  in  the  kidneys, 

(1)  Brocke,  De  vesica  urinaricc  appendicibus , Strasburg-,  1754. — C.  Bell,  Surgical 
observations , pt.  iv.,  London,  1817. 

(2)  Meckel,  Handbuch  der  pathologischen  Anatomie , vol.  ii.,  p.  424. 

(3)  O.  Heer,  De  renum  niorbis,  Halle,  1790,  (ab.  i. 

(4)  Bajllie,  Engravings,  fase,  iv.,  tab.  viii. 


388 


DESCRIPTIVE  ANATOMY. 


B.  BLADDER. 

§ 2385.  When  the  bladder  enlarges,  its  membranes  are  also  gene- 
rally thickened  by  inflammation,  become  firmer,  adhere  more  to  each 
other,  or  are  destroyed  in  parts. 

The  muciparous  glands  of  the  inner  membrane  are  often  enlarged 
in  catarrh  of  the  bladder. 

Irregular,  rounded,  reddish  tumors  of  various  sizes  are  developed  on 
this  membrane,  principally  at  the  lower  part  of  the  posterior  wall  of 
the  bladder  ; these  rest  upon  a narrower  base,  and  have  no  determinate 
texture.  These  tumors,  called  funguses  of  the  bladder  ( fongus  vesicas 
urinariœ),  are  observed  principally  in  males,  and  at  an  advanced  age. 

III.  FOREIGN  BODIES. 

§ 2386.  Of  the  foreign  bodies  most  frequent  in  the  urinary  system, 
and  consequently  in  the  ureters  and  bladder,  entozoaries  are  rare, 
and  calculous  concretions  are  very  frequent. 

A.  ENTOZOARIES. 

§ 2387.  The  entozoaries  in  the  urinary  system  are  : 

1st.  Hydatids,(l)  which  occur  particularly  in  the  kidneys,  and  per- 
haps are  always  primitively  developed  there. 

2d.  The  strongylus  gigas,  which  exists  in  the  kidneys. 

3d.  Two  other  worms,  as  yet  undetermined,  which  were  voided 
with  the  urine. (2) 

B.  CALCULI. 

§ 2388.  The  urinary  calculiez)  present  several  general  and  special 
important  characters. 

(1)  Baillie,  loc.  cit .,  tab.  vii-viii. 

(2)  Lawrence,  Case  of  a woman  who  voided  a large  number  of  worms  by  the 
urethra  ; in  the  Med.  chir.  trans.,  vol.  ii. 

(3)  Tenon,  Sur  la  nature  des  calculs  ; in  the  Mém.  de  Paris , 1765. — Scheele,  Un- 
tersuchung des  Blasensteins  ; in  the  Schwedische  Abhandlungen , vol.  xxxvii. — E. 
Sandifort,  De  calculo  renal.  ; in  the  Obs.  anat.  pathol.,  1777,  vol.  i.,  p.  6:  De  calculis 
renum  et  vesicœ , ibid.,  vol.  i v.,  p.  7 ; De  lethali  urinœ  suppressions  ex  calculo  urethrae 
inserto,  indeque  natâ  duplici  hujus  canalis  rupturâ  ; ibid.,  vol.  iii.,  p.  3. — F.  A. 
Walter,  Anatomisches  Museum , th.  i.,  Berlin,  1796. — Wollaston,  On  gouty  and  uri- 
nary concretions  ; in  the  Phil,  trans.,  1797. — Pearson,  ibid.,  1798. — Fourcroy,  in  the 
Annales  du  Museum , vol.  i. — Brande,  in  the  Phil,  trans.,  1808. — Magendie,  Re- 
cherches sur  la  gravclle,  Paris,  1818. — Prout,  An  inquiry  into  the  nature  and  treat- 
ment cfbiabetes,  calculus , and  other  affections  of  the  urinary  organs,  with  notes  and 
additions,  by  S Colhoun,  M.  D.,  Philadelphia,  1826. — Marcet,  Essai  sur  les  affections 
calculeuses,  Paris,  1823. — F.  A.  G.  Hoffmeister,  De  cakulis  urinariis  collectanea 
quœdàm,  Leipsic,  1821. 


OF  THE  URINARY  SYSTEM. 


389 


§ 2389.  Their  general  characters  relate  to  their  situation,  texture, 
form,  volume,  number,  mode  of  development,  and  effect  on  the  organs 
which  contain  them. 

1st.  Situation.  It  varies  both  in  itself,  and  in  its  relations  with  the 
urinary  system. 

a.  Calculi  occur  in  the  cavity  or  in  the  paiietes  of  this  system. 

The  calculous  concretions  in  the  first  are  much  more  common  than 

in  the  second. 

Of  the  four  parts  in  which  they  can  be  developed,  the  pelvis,  the 
ureter,  the  bladder,  and  the  urethra,  they  occur  most  frequently  in  the 
bladder,  and  most  rarely  in  the  urethra.(l) 

The  portion  of  the  cavity  of  the  urinary  system  which  contains 
them,  particularly  of  the  bladder,  is  not  generally  separated  from  the 
rest  by  an  abnormal  septum.  Sometimes,  however,  the  calculi  are 
inclosed  in  a special  sac,  which  communicates  with  the  common  ca- 
vity by  a narrow  opening  ; they  are  then  termed  encysted  calculi. 

This  state  is  doubtless  in  most  cases  the  source  of  the  calculi  exist- 
ing in  the  parietes  of  the  bladder.  We  must  admit  that  the  communi- 
cation at  first  existing  is  finally  obliterated  ; it  is  impossible  to  suppose 
that  the  concretions  were  formed  except  within  the  cavity  of  the 
bladder. 

b.  Most  generally,  and  even  most  always,  the  urinary  calculi  are 
entirely  loose  ; but  sometimes  they  are  attached  to  the  inner  face  of 
the  bladder  by  mucus  or  thickened  and  coagulated  fibrine,  which  exists 
between  their  prominences. (2) 

2d.  Texture.  The  urinary  calculi  are  generally  formed  of  superim- 
posed layers,  more  or  less  distinct  and  more  or  less  concentric.  Their 
centre  also  is  usually  formed  by  a nucleus,  which  most  generally 
consists  of  a small  mass  of  uric  acid,  more  rarely  of  a foreign  body 
accidentally  introduced  into  the  urinary  apparatus,  particularly  the 
bladder. 

The  different  layers  are  generally,  but  not  always,  similar  in  their 
chemical  composition.  They  are  always  formed  of  at  least  two  sub- 
stances, one  solid,  the  other  softer  and  originally  fluid,  which  unites 
and  connects  the  particles  of  the  preceding. 

3d.  Form.  The  urinary  calculi  are  more  or  less  oblong  and  rounded, 
and  generally  smooth  and  a little  flattened.  This  character  depends 
in  great  part  on  the  influence  of  the  organ  which  contains  them,  the 
bladder  being  round.  The  form  of  the  renal  calculi  demonstrates  par- 
ticularly the  great  influence  of  the  form  of  the  organ  on  that  of  these 
concretions. 

(1)  Ehrlich  has  described  a very  remarkable  renal  calculus.  (Loc.  cit.,  vol.  ii., 
p.  24.) 

(2)  Meckel,  Handbuch  der  pathologischen  Anatomie , vol.  ii.,  pt.  ii.,  p.  444. — How- 
ship,  loc.  cit.,  p.  249,  tab.  iii.,  fig.  5. — Bell,  Surgical  observations , Loudon,  1818,  pt. 
iv.,  p.  444,  tab.  i. 


VOL.  III. 


50 


390 


DESCRIPTIVE  ANATOMY. 


4th.  Volume.  The  size  of  the  calculi  varies  from  that  of  an  almost 
invisible  grain  to  a diameter  of  several  inches  ; they  are  sometimes  so 
large  that  they  completely  fill  the  bladder,  and  even  distend  it. 

5th.  Number.  Usually  there  is  only  one,  or  there  are  but  few. 
When  many  exist  their  chemical  composition  is  generally,  but  not 
always,  the  same. 

6th.  J\lode  of  development.  We  may  mention,  as  a general  rule, 
that  the  formation  of  the  calculi  depends  either  on  the  abnormal  state 
of  the  urinary  system,  or  on  the  presence  of  a foreign  body  accidentally 
introduced  into  the  bladder. 

The  abnormal  state  of  the  urinary  system  may  vary  in  several  dif- 
ferent modes.  The  secretory  portion  is  generally  affected,  so  that  an 
alteration  in  the  chemical  composition  of  the  urine  is  most  generally 
the  cause  of  the  formation  of  calculi.  This  accidental  production  de- 
pends more  rarely  on  an  abnormal  arrangement  in  the  bladder,  or  the 
excretory  portion  of  the  urinary  system.  It  may,  however,  be  caused 
by  a mechanical  obstacle  to  the  emission  of  the  urine,  especially  by 
sacs  in  the  parietes  of  the  bladder,  by  the  hernia  of  the  bladder,  or  by 
strictures  of  the  urethra.  Calculi  have  even  been  developed  between 
the  glans  and  the  prepuce.(l) 

7th.  Influence  on  the  urinary  system.  This  influence  varies.  When- 
ever they  are  developed,  the  urinary  calculi,  being  foreign  bodies, 
cause  more  or  less  acute  pains,  the  intensity  and  nature  of  which 
depend  on  their  form,  situation,  number,  and  size,  independent  of  the 
degree  of  sensibility  of  the  patient. 

The  changes  caused  by  them  in  the  form  of  the  urinary  system  are, 
the  distension  of  the  membranous  parts,  particularly  the  ureters,  the 
thickening  of  the  muscular  portion,  consequently  of  the  bladder,  which 
often  attends  their  enlargement,  but  still  more  frequently  the  contrac- 
tion of  its  cavity,  finally  rupture,  which  is  more  rare,  and  which  occurs 
particularly  in  the  urethra. 

§ 2390.  The  peculiar  characters  of  the  urinary  calculi  relate  prin- 
cipally and  almost  exclusively  to  their  chemical  composition. 

Chemical  analysis  has  discovered  in  them  at  this  date  uric  acid,  the 
phosphate  of  lime,  the  ammoniaco-magnesian  phosphate,  the  oxalate 
of  lime,  and  the  cystic  oxyd.  There  have  been  found  also,  but  more 
rarely,  less  constantly,  and  in  less  quantity,  silex,  carbonate  of  lime, 
iron,  and  two  other  peculiar  substances,  the  xanthic  oxyd,  and  a fibri- 
nous substance.  Wollaston  and  Brande  doubt  the  presence  of  urate 
of  ammonia,  admitted  by  Fourcroy  and  Vauquelin,  and  consider  this 
salt  as  produced  by  the  chemical  analysis  ; but  we  cannot  conclude 
positively  from  the  arguments  with  which  their  opinion  is  supported 
that  it  never  occurs  in  common  calculi. 

(1)  Walter,  Obs.  anat.,  Berlin,  1775,  p.  74.— Penada,  in  Brera.— Meckel,  Handbuch 
der  pathologischen  Anatomie , vol.  ii.(  pt.  ii.,  p.  444. 


OF  THE  URINARY  SYSTEM. 


391 


Sometimes  these  substances  are  distinct,  and  sometimes  they  com- 
bine in  a greater  or  less  number  to  form  a concretion,  whence  nume- 
rous kinds  of  calculi  are  formed. 

The  simple  calculi  are  : 

1st.  Those  of  uric  acid,  which  are  smooth,  of  a brownish  red, 
and  generally  composed  of  concentric  layers.  They  are  the  most 
common. 

2d.  Those  of  phosphate  of  lime,  which  are  proportionally  rare,  are 
white,  and  composed  of  layers  easily  separated. 

3d.  Those  of  oxalate  of  lime  are  round,  generally  rough  and  brown  ; 
sometimes  they  are  smooth,  and  seem  to  form  always  in  the  kidneys. 

4th.  Those  of  the  cystic  oxyd,  more  property  the  renal  oxyd,  be- 
cause this  substance  is  very  probably  developed  in  the  kidneys.  These 
calculi  are  yellowish  and  semitransparent.  They  have  no  lamellar 
texture. 

5th.  Those  of  xanthic  oxyd,  which  have  been  seen  only  once. 

6th.  Those  of  fibrinous  matter,  which  also  have  been  seen  only 
once. 

The  calculi  composed  of  different  substances  which  do  not  form  as 
many  separate  layers  are  : 

1st.  Those  of  the  ammoniaco-magnesian  phosphate,  or  the  fusible 
calculi  (calculus  fusibilis)  of  Wollaston  and  Marcet,  the  most  common 
next  to  those  of  the  uric  acid.  They  are  white,  and  more  friable  than 
those  of  the  other  species.  The  ammoniaco-magnesian  phosphate 
often  predominates,  although  it.  seldom  or  never  forms  it  alone.  The 
calculi  formed  around  the  foreign  bodies  introduced  into  the  bladder, 
those  developed  in  ischuria,  or  between  the  prepuce  and  the  glans, 
are  most  generally  of  this  nature,  because  in  this  case  the  urine  is 
more  or  less  decomposed. 

2d.  The  more  complex  calculi  are  distinguished  by  their  indetermi- 
nate form,  their  color,  their  structure,  which  is  not  evidently  in  strata, 
and  their  hardness. 

Finally,  among  the  compound  calculi,  there  are  some  in  which  the 
different  layers  are  formed  bjr  as  many  distinct  substances.  The  num- 
ber of  these  substances  varies  from  two  to  four  : but  there  are  gene- 
rally but  two,  the  uric  acid,  with  a phosphate  or  oxalate  of  lime,  with 
sometimes  another  phosphate,  or  with  silex.  In  a calculus  formed  by 
four  layers,  Marcet  has  found,  from  the  centre  to  the  circumference, 
cystic  oxyd,  phosphate  of  lime,  oxalate  of  lime,  and  the  ammoniaco- 
magnesian-phosphate. 


392 


DESCRIPTIVE  ANATOMY. 


ARTICLE  THIRD. 

RENAT,  CAPSULES. 

I.  NORMAL  STATE. 

A.  SITUATION. 

§ 2391.  The  renal  capsules  ( renes  succenluriati , capsula , s.  glan- 
dula  suprarenales , s.  atrabiliares),(  1)  are  triangular  bodies,  very  flat 
from  before  backward,  resting  directly  on  the  kidneys,  to  which  they 
are  united  by  a short  cellular  tissue.  They  occupy  their  upper  extre- 
mity and  the  upper  part  of  their  internal  edge.  Like  them,  they  are 
situated  on  the  outside  of  the  peritoneum. 

B.  FORM  AND  VOLUME. 

§ 2392.  We  have  mentioned  the  general  form  of  the  renal  capsules. 
They  are  more  long  than  broad,  that  is,  they  extend  farther  from  above 
downward  than  from  right  to  left.  They  are  only  about  one  line  thick. 
Their  form  differs  on  the  two  sides  : that  of  the  left  side  is  a little  higher 
and  narrower  than  that  of  the  right  : the  left  is  from  fifteen  to  seven- 
teen lines  long,  and  about  three  broad  : the  right  is  generally  from 
fourteen  to  fifteen  lines  long,  and  twelve  or  fourteen  broad. 

We  remark  on  their  external  face  the  fissures  through  which  the 
blood-vessels  enter  and  depart.  The  left  capsule  usually  presents  for- 
ward a longitudinal  fissure,  while  there  are  two  on  the  right  side,  an 
anterior  and  a posterior. 

C.  WEIGHT. 

§ 2393.  Each  renal  capsule  in  the  adult  weighs  about  one  drachm. 

D.  CONSISTENCE  AND  COLOR. 

§ 2394.  These  organs  are  quite  firm  but  brittle.  Their  color  is  yel- 
lowish brown  externally,  and  a deep  reddish  brown  internally. 

(1)  A.  M.  Valsalva,  Diss.  anat.,  III. — B.  Morgagni,  Epist.  anat.  XX. — Duver- 
noy,  Comm.  Petrop.,  vol.  ii. — Bœckler,  De  thyroid 'œ,  ihymi  et  glandularum  supra- 
renaliumfunctionibus,  Strasburg,  1753. -—J.  C.  Mayer,  De glandulis  suprarenalibus, 
Frankfort,  1784. — Riegels,  De  usu  glandularum  superrenaliumnecnon  de  origine 
adipis , Copenhagen,  1790. — F.  F.  Leonhardi,  Diss.  de  glandulis  suprarenalibus , 
Dresden,  1810. — J.  F.  Meckel,  Abhandlungen , p.  1-277. 


OF  THF.  URINARY  SYSTEM. 


393 


E.  TEXTURE. 

§ 2395.  They  are  composed  of  two  substances,  one  external,  more 
consistent  and  yellowish,  the  other  interna],  softer  and  of  a deeper 
brownish  red.  The  first  is  evidently  formed  of  perpendicular  fibres, 
which  are  directed  from  without  inward.  These  two  substances  are 
often  intermixed,  whence  the  capsule  appears  spotted  externally.  The 
external  is  divided  more  or  less  easily  into  rounded  lobes,  which  may 
themselves  be  divided  into  lobules,  and  it  is  covered  by  a very  thin  se- 
rous membrane,  which  intimately  adheres  to  its  surface. 

According  to  several  anatomists,  the  renal  capsules  contain  a more 
or  less  complex  cavity.  However,  after  much  research,  wre  are  obliged 
to  adopt  the  opposite  opinion  ;(1)  we  think  that  there  is  normally  no 
cavity,  that  it  does  not  form  till  after  death,  and  that  it  results  either 
from  the  spontaneous  decomposition  of  the  inner  substance,  which  is 
not  very  consistent,  or  fiom  this  substance  being  destroyed  by  hand- 
ling it. 

The  substance  of  the  renal  capsules,  particularly  the  internal,  is 
very  intimately  and  directly  connected  with  the  veins,  for  the  liquids 
and  air  injected  into  these  vessels  easily  penetrate  them,  and  the  air 
often  forms  in  them  a cavity,  they  are  so  soft. 

§ 2396.  The  renal  capsules  are  imperfect  glands,  as  they  have  no 
excretory  ducts.  In  fact,  these  ducts  have  been  admitted  by  some 
anatomists  of  note,  as  Bartholini,(2)  Peyer,(3)  Valsalva, (4)  Ranby,(5) 
Kulmus,(6)  Heuermann, (7)  and  Bendt.(8)  The  capsules  communi- 
cate with  the  testicles,  according  to  Bartholini,  Peyer,  Valsalva,  and 
Ranby  : with  the  thoracic  canal  according  to  Kulmus,  with  the  pelves 
of  the  kidneys  according  to  Heuermann  and  Bendt.  But  very  careful 
and  numerous  dissections  have  led  us  to  the  contrary  opinion.  The 
absence  of  an  excretory  duct  in  these  organs  seems  more  probable,  as 
it  accords  with  the  researches  of  Morgagni. 

II.  DIFFERENCES  PECULIAR  TO  THE  RACES. 

§ 2397.  Some  writers  have  asserted  that  the  renal  capsules  were 
larger  in  negroes  than  in  the  Caucasian  race,  and  that  their  medullary 
substance  was  darker. (9)  We  have  seen  nothing  of  this  in  dissecting 

a negro,  although  we  had  previously  observed  it  in  a negress.(lO) 

(1)  See  our  Abhandlungen,  p.  17. 

(2)  Rhodii,  Mantissa,  p.  36. 

(3)  Obs.  anat.;  obs.  32. 

(4)  Diss.  anat.,  111.  Morgagni,  Ep.  an.  XX. 

(5)  Phil.  Irans.,  p.  385. 

(6)  Brest.  Samml.  1722,  Feb. 

(7)  Physiologie,  vol.  iv.  p.  97. 

(8)  Defabric,  vise,  uropcet.,  p.  17. 

(9)  Cassan,  Observ.  med.;  in  Hufeland,  Annalen  der  franzœsiscken  Arrneywis- 
senschaft,  vol.  i.  p.  475. 

(10)  Handbuch  der  pathologischen  Anatomie,  vol,  i,  p.  648. 


394 


DESCRIPTIVE  ANATOMY. 


III.  DIFFERENCES  DEPENDENT  ON  DEVELOPMENT. 

§ 2398.  The  renal  capsules  are  very  easily  distinguished  in  the 
fetus  of  two  months. 

Their  proportional  size  gradually  diminishes  on  their  first  appear- 
ance, and  the  same  is  true,  at  least  frequently,  of  their  absolute  size 
after  birth.  They  become  thinner  and  dryer,  wrinkle,  and  even  en- 
tirely disappear  in  oldage.(l)  At  the  end  of  the  third  month  they 
are  a little  larger  and  heavier  than  the  kidneys  : at  four  months  they 
are  equal  in  size  to  these  glands,  but  they  are  lighter,  because  their 
tissue  is  looser.  At  the  commencement  of  the  sixth  month  they  are 
only  half  as  large  as  the  kidneys,  but  their  weight  is  to  that  of  these 
latter  as  2 : 5,  since  each  capsule  weighs  ten  grains,  and  each  kidney 
twenty-five.  In  the  full-grown  fetus  the  proportion  is  about  as  1 : 3, 
each  capsule  usually  weighs  a little  more  than  four  scruples,  and  each 
kidney  more  than  half  an  ounce.  In  the  adult,  on  the  contrary,  the 
relation  is  as  1 : 23,  for  the  capsule  weighs  one  drachm,  and  the  kid- 
ney three  and  a half  ounces. 

These  organs  are  composed  of  lobes,  which  are  at  first  more  nume- 
rous and  more  distinct  than  in  the  adult  ; but  they  do  not  always  con- 
tain a cavity  in  the  early  periods  of  life. 

IV.  FUNCTION. 

§ 2399.  It  is  very  difficult  to  mention  the  function  of  the  renal  cap 
suies,  although  their  great  size  before  birth  indicates  their  importance. 

We  have  every  reason  to  think,  that  like  the  liver,  the  spleen,  the 
thyroid,  and  the  thymus  glands,  they  contribute  directly  to  the  perfect 
formation  of  the  blood.  Their  great  size  in  the  fetus,  their  free  com- 
munication with  the  venous  system,  and  their  nearness  to  the  ascend- 
ing vena-cava,  are  at  least  so  many  circumstances  in  favor  of  this  con- 
jecture. 

Those  observers  who  admit,  an  excretory  duct  to  the  genital  organs, 
necessarily  connect  the  renal  capsules  directly  with  them.  Other 
facts,  particularly  their  simultaneous,  considerable  development  in  seve- 
ral orders  of  the  mammalia  had  suggested  the  same  idea  to  us, (2)  be- 
fore we  knew  that  it  belonged  to  another,  but  we  could  not  describe 
the  mode  in  which  the  renal  capsules  and  the  genital  organs  co-ope- 
rated. 

We  may  also  mention  in  support  of  this  hypothesis,  the  coincidence 
of  anomalies  in  the  renal  capsules  with  those  in  the  genital  organs. 
Thus,  Vauquelin  has  found  the  capsules  ossified  in  a cat,  from  which 
the  ovaries  had  been  extirpated. (3)  Lobstein  has  found  that  of  the 
left  side  tripled  in  size  by  a chalky  mass  in  a man  who  had  long  been 

(1)  Bichat,  Anal,  descript,  vol.  v.  p.  462. 

(2)  Abhandlungen , 1806,  p.  164. 

(3)  Fourcroy,  Médecine  éclairéa,  vol.  i.  p.  236 


Of  THE  URINARY  SYSTEM. 


395 


affected  with  syphilis.(l)  We  have  found  these  organs  unusually 
large  in  two  individuals  much  addicted  to  venery,(2)  and  deformed  in 
a female  shortly  after  parturition,  in  whom  the  uterus  and  one  of  the 
ovaries  also  presented  a similar  formation. (3)  Otto  has  seen  them 
twice  the  usual  size,  in  one  case  where  the  genital  organs  were  very 
much  developed. (4) 

The  great  simultaneous  development  of  these  two  orders  of  organs 
in  the  fetus,  the  coincidence  of  their  smallness,  and  even  the  simul- 
taneousness of  their  absence  with  the  development  of  the  encephalon, 
between  which  and  the  genital  organs  there  is  so  striking  a connection 
in  an  opposite  sense,  are  circumstances  in  favor  of  this  hypothesis. 
Another  conjecture  very  similar  to  this,  is  to  consider  the  renal  cap- 
sules as  an  imperfect  rudiment  of  the  genital  organs, (5)  although  it 
seems  to  us  too  doubtful  to  think,  that  if  they  were  connected  with  the 
kidneys  more  intimately,  an  excess  of  energy,  a momentary  excite- 
ment alone  would  be  necessary  for  this  connection,  acting  like  a real 
copulation,  should  cause  the  renal  capsules  to  produce  a new  being. 

It  seems  to  us  less  probable  that  the  renal  capsules  have  a mechani- 
cal’or  dynamical  relation  with  the  kidneys,  because,  that  when  these 
latter  are  displaced,  the  capsules  always  preserve  their  normal  situ- 
ation, so  that  the  two  organs  are  then  more  or  less  distant. 

Finally,  it  is  still  less  probable  that  they  contribute  to  produce  the 
fat. (6) 


V.  ABNORMAL  STATE. 

§ 2400.  The  renal  capsules  are  very  rarely  abnormal, (7)  and  inas- 
much as  their  anomalies  consist  in  alterations  of  texture,  we  may  con- 
jecture with  great  probability,  that  they  depend  on  the  premature  ex- 
tinction of  the  great  power  primitively  possessed  by  the  organ. 

A very  general  primitive  anomaly,  is  their  extreme  smallness,  or 
their  entire  deficiency,  which  attends  the  imperfect  development  of  the 
encephalon,  and  the  upper  half  of  the  body  generally.  Only  two  or 
three  cases  of  this  kind  are  known,  where  the  renal  capsules  were 
found  of  their  usual  size.  Their  imperfect  development  not  only  at- 
tends alterations  of  the  cerebrum,  but  the  suspended  development  of 
this  viscus  generally,  particularly  congenital  hydrocephalus. 

(1)  Rapport  sur  les  travaux  anatomiques , Strasburg-,  1805. 

(2)  Abhandlungen,  p.  185-186. 

(3)  Ibid.,  p.  159. 

(4)  Pathologisch-anatomische  Beobachtungen,  1816,  p.  139. 

(5)  L.  C.  Treviranus,  Untersuchungen  über  wichtige  Gegenstände  der  Naturwis- 
senschaft und  Medicin,  Gottingen,  1803,  p.  184. 

(6)  Riegels,  loc.  cit. 

(7)  Lauth,  in  Lobstein,  loc.  cit.,  p.  36. — Dupuytren,  in  Meckel,  Abhandlungen,  p. 
141.  Our  observations  perfectly  agree  with  his. 


396 


DESCRIPTIVE  ANATOMY. 


The  number  of  the  renal  capsules  soinetimes(  1)  increases,  an  in- 
teresting phenomenon,  as  it  resembles  one  rather  common  in  an  adja- 
cent organ,  the  spleen. 

It  is  difficult  to  determine  whether  this  state  be  only  a simple  divi- 
sion, or  whether  we  should  consider  it  as  a real  increase  in  the  sub- 
stance of  the  renal  capsules.  Considered  in  the  last  point  of  view,  it 
would  gradually  lead  to  the  hypertrophy  of  these  organs,  some  cases 
of  which  are  known. (2) 

This  hypertrophy  is  rare  : we  may  presume  that  it  generally  de- 
pends on  an  alteration  of  texture,  and  it  seems  particularly  coincident 
with  anomalies  in  the  genital  organs. 


CHAPTER  IV. 

OF  THE  GENITAL  SYSTEM. 

§ 2401.  The  organs  of  generation , the  genital,  parts  ( partes , s.  or- 
gana sexualia, genitalia , s.  generation's  inserventia),(3 ) principally  serve 
to  perpetuate  the  species,  while  the  existence  of  the  other  systems  is 
directly  connected  only  with  that  of  the  individual.  They  however  are 
directly  connected  with  the  organism  of  the  individual,  as  is  de- 
monstrated by  the  consequences  of  their  absence,  whether  primitive  or 
congenital,  or  consecutive  and  accidental,  or  produced  by  a determina- 
tion of  the  will.  The  sexual  character  which  is  imprinted  on  the 
whole  organism,  is  most  evident  in  them.  Of  all  the  organs  then, 
these  differ  the  most  in  the  twTo  sexes.  A superficial  examination 
would  lead  to  the  conclusion,  that  the  genital  organs  in  the  male  are 
entirely  different  from  those  of  the  female,  and  that  they  cannot  be 
compared.  But  if  we  compare  them  in  any  animal,  or  even  in  man, 
we  shall  be  satisfied  that  they  have  originally  the  same  form,  that 
they  correspond  perfectly  in  respect  to  number,  their  essential  peculiari- 
ties in  structure  and  function,  that  they  differ  only  in  size  and  situation, 
and  that  consequently,  the  analogies  between  them  are  much  greater 
than  the  differences,  and  that  they  should  be  regarded  as  modifications 
of  one  and  the  same  primitive  type. 

It  is  convenient  to  add  the  history  of  the  mammæ  to  that  of  the 
genital  system,  since  they  contribute  but  slightly,  or  not  at  all,  to  the 
organism  of  the  individual,  while  in  their  quality  of  nutritious  organs 
of  the  infant,  they  exert  a great  influence  on  the  preservation  of  the 
species.  Besides,  they  do  not  differ  less  in  the  two  sexes  than  the 


(1)  Duvernoy,  loc.  cit.— Morgagni,  Ep.  XX.  a.  43.— Otto,  Seltne  Beobachtungen, 
vol.  lxxxiv. 

(2)  Harder  Apiar.,  obs.  61. 

(3)  F.  Plazzoni,  De  partibus  gcnerationi  inservientibus,  libri  III,  Padoue,  1521.— 
W.  Rolfink,  Ordo  et  methodus  generationi  dicatarum partium  per  anatome n cognos- 
cendi fabricant,  Jena,  1664. — Id.,  De  sexus  utriusque  partibus  genitalibus  specimen , 
Leipsic,  1675.— Van  Horne,  Prodromus  obscrvationum  suaruni  circa  parles  géni- 
tales in  utroque  sexu,  Leyden,  1668. 


OF  THE  GENITAL  SYSTEM. 


397 


other  organs  of  generation.  It  would  be  better  then,  instead  of  em- 
ploying the  expressions  sexual  parts  and  genital  parts  indiscriminately, 
as  is  generally  done,  to  confine  the  latter  term  to  the  organs  which 
produce  the  new  being,  that  is,  to  the  proper  genital  organs. 

All  these  parts  differ  from  most  others,  as  their  active  state  is  pro- 
portionally very  slight,  for  it  generally  does  not  extend  much  beyond 
the  half  of  existence,  during  which  it  appears  only  at  long  intervals, 
and  requires  also,  in  order  to  be  brought  into  action,  very  general, 
and  often  very  great  changes,  both  in  the  mode  of  vitality,  and  in  the 
structure  of  the  organs. 


ARTICLE  FIRST. 

GENITAL  ORGANS  IN  THE  NORMAL  STATE. 

I.  PROPER  GENITAL  ORGANS. 

§ 2402.  The  proper  genital  organs  occupy  the  lower  part  of  the 
trunk,  and  are  situated  within  and  on  the  surface  of  the  pelvis. 

Those  of  the  male  and  female  differ  principally’'  in  this  respect,  that 
the  first  are  situated  more  externally’,  and  are  arranged  more  longitu- 
dinally, while  the  second  are  placed  more  internally.  Those  parts 
which  in  the  male  are  situated  on  the  outside  of  the  abdominal  cavity, 
exist  in  the  female  within  the  cavity  of  the  pelvis,  and  even  those 
which  occupy  the  cavity  of  the  pelvis  in  the  male,  are  pushed  forward 
so  much  that  they  are  found  directly  below  the  common  integuments. 
Thus,  while  the  external  genital  organs  in  the  female,  those  seen 
without  opening  the  body,  are  much  fewer  and  smaller  than  the  in- 
ternal, the  opposite  is  true  of  the  male  ; but  we  shall  demonstrate  here- 
after, that  this  difference  also  does  not  exist  during  the  whole  of  fife. 

§ 2403.  The  best  mode  is  to  divide  the  genital  organs,  in  the  two 
sexes,  according  to  the  functions  of  their  different  constituent  parts  ; 
into  the  proper  genital  or  formative  organs  ( organa  generationis,  s. 
formantia ),  and  the  organs  of  copulation  ( organa  copulationis) . 

The  formative  organs  in  the  man,  are  the  testicles,  with  their  excre- 
tory ducts,  the  prostate  gland,  and  the  glands  of  Cowper  : in  the  female 
the  ovaries  wfith  their  excretory  ducts,  the  Fallopian  tubes,  and  the 
uterus. 

The  organs  of  copulation  are,  in  the  male,  the  penis  ; in  the  female, 
the  vagina  and  the  vulva. 

§ 2404.  In  both  sexes  the  genital  organs  are  situated  at  the  lowest 
extremity  of  the  trunk,  consequently,  directly  opposite  to  the  encepha- 
lon. In  both  sexes  they  differ  from  the  .other  organs  in  the  symmetri- 
cal arrangement,  then  constituent  parts  existing  in  pairs,  or  in  the 
contrary  case,  being  situated  on  the  median  line  of  the  body’,  which 
divides  them  into  two  equal  parts. 

VOL.  III. 


51 


398 


DESCRIPTIVE  ANATOMT. 


A.  GENITAL  ORGANS  OF  THE  FEMALE. 

§ 2405.  It  is  convenient  to  commence  with  the  genital  organs  of 
the  female,(l)  since  the  genital  organs  of  the  two  sexes  primarily  as- 
sume their  form. 


I.  FORMATIVE  ORGANS. 

§ 2406.  The  ovaries  and  the  Fallopian  lubes  deserve  to  be  ex- 
amined first,  on  account  of  the  period  at  which  they  appear,  and  their 
importance. 


A.  OVARIES. 

a.  Form,  situation,  volume,  and  weight. 

§ 2407.  The  ovaries  ( ovaria , s.  testes  muliebres)(2)  are  situated 
at  the  upper  part  of  the  cavity  of  the  pelvis,  on  the  sides  of  the  uterus, 
to  which  they  are  attached  only  by  the  ligament  of  the  ovary  ( l . ovarii ), 
a portion  of  the  fold  of  the  peritoneum,  which  attaches  the  uterus  to 
the  pelvis,  and  is  termed  the  round  ligament.  They  are  rounded  and 
oblong.  Their  anterior  and  posterior  faces  are  convex.  Their  upper 
edge  is  also  convex  and  loose.  The  lower  is  straight  or  a little  con- 
cave, presenting  a real  vascular  fissure  ( hylus ).  They  rest  by  this 
latter  edge  on  the  upper  part  of  the  broad  ligament.  They  become 
thinner  towards  their  internal  and  external  extremities,  but  particularly 
toward  the  former. 

Their  surface  is  usually  smooth  in  virgins,  and  generally  uneven  and 
lacerated  in  aged  females.  When  perfectly  developed,  they  are  about 
an  inch  and  a half  long,  about  four  or  five  lines  high,  and  a little  less 
in  thickness.  They  weigh  about  a drachm  and  a half 

b.  Structure. 

§ 2408.  The  ovaries  are  covered  externally  by  the  peritoneum, 
below  which  is  a very  solid  and  very  resisting  white  fibrous  membrane 
( tunica  albuginea).  These  two  layers  are  inseparably  united.  The 
internal  is  perforated  at  the  lower  edge  of  the  gland  by  vessels  which 
pass  through  it,  and  are  distributed  in  its  tissue. 

(1)  R.  de  Graaf,  De  mulierum  organis  generationi  inser vient ibus,  Leyden,  1672. 
J.  Palfyn,  Description  anatomique  des  parties  de  la  femme  qui  servent  à la  géné- 
ration, Leyden,  1708.— D.  Santorini,  Obs.  anat.  cap.  XI.  De  mulierum  partibus  pro- 
creationi  dalis. — J.  G.  Gunz,  Observationes  de  utero  et  naturalibus  fceminarum, 
Leipsic,  1753. 

(2)  C.  Bartholin,  De  ovariis  mulierum  et  generationis  historia,  Rome,  1677. — 
Fasch,  De  avaria  malierum,  Jena,  1681— Motz,  De  structura,  usv,  et  morbU  ovari- 
orum,  Jena,  1789. 


OF  THE  GENITAL  SYSTEM. 


399 


When  we  cut  the  ovaries,  their  tissue  appears  brownish  red,  they 
are  very  vascular,  firm,  and  solid,  and  vesicles  are  situated  within  them. 

§ 2409.  These  vesicles(l)  are  termed  the  ovula  of  Graaf  (vesiculoe, 
s.  ovula  Gh'aafiana ),  although  they  were  known  previously  by  Vesa- 
lius(2)  and  Fallopius. (3) 

In  the  normal  state  they  are  composed  of  a thin,  smooth,  and  serous 
membrane,  which  adheres  intimately  to  the  substance  of  the  gland  ; 
they  are  entirely  closed  and  filled  with  a clear  and  limpid  fluid.  They 
vary  in  size,  and  they  seem  to  be  developed  successively.  The  largest 
are  about  three  lines  in  diameter,  they  are  more  numerous  on  the  edge 
of  the  ovary  than  in  the  centre.  In  virgins  their  number  varies  from 
eight  to  twenty. 

B.  FALLOPIAN  1 UBES. 

§2410.  The  Fallopian  tubes  ( tubas  Fallopiance,  s.  meatus  semi- 
narii)( 4)  are  the  excretory  ducts  of  the  ovaries.  They  are  situated 
before  and  below  these  organs,  then  go  from  without  inward  toward 
the  upper  edge  of  the  uterus,  passing  through  the  upper  end  of  the 
broad  ligament  ( ala  vespertilionum ),  to  which  they  are  attached. 

They  are  very  tortuous,  especially  in  their  external  portion,  and 
gradually  enlarge,  so  that  their  diameter,  which  is  only  half  a line  on 
the  inside,  becomes  by  degrees  three  and  four  lines.  They  open  into 
the  abdomen  ( ostium  abdominale)  by  a mouth  surrounded  with  a fim- 
briated edge,  called  the  morsus  diaboli.  This  opening  projects  much 
on  the  outside  of  the  outer  extremity  of  the  ovary.  The  internal  orifice 
(ostium  uterinum)  opens  in  the  angle  formed  by  the  union  of  the  upper 
edge  of  the  uterus  with  its  sides.  There  is  no  mark  of  valve  or  promi- 
nence here.  Each  tube  is  about  five  inches  long. 

§2411.  The  tubes  are  covered  by  the  peritoneum,  which  forms 
their  external  tunic,  and  which  is  continuous  with  the  inner  membrane 
on  the  edges  of  the  abdominal  orifice. 

Below  the  peritoneal  tunic  is  the  middle  membrane,  in  which  we 
cannot  usually  observe  any  fibres,  but  it  is  sometimes  composed  in 
vigorous  females  of  two  muscular  layers,  which  are  formed,  the  ex- 
ternal by  longitudinal  fibres,  and  the  internal  by  circular  fibres. (5) 

The  internal  mucous  membrane  is  smooth,  and  presents  numerous 
longitudinal  folds. 

II)  Bartholin,  De fœminarum  oris,  Leyden,  1684. 

(2)  De  corporis  humanifabricâ,  lib.  v.  cap.  xv.  p.  459. 

(3)  Obs.  anat.;  in  the  Opp.  omn.  Venice,  1606,  vol.  i.  p.  106. 

(4)  Bartholin,  De  tubis  uteri , Leyden,  1684. 

IB)  Santorini,  loc.  cit. 


400 


DESCRIPTIVE  ANATOMY, 


C.  UTERUS. 

§ 2412.  The  uterus  or  matrix(l)  is  the  largest  of  those  parts  which 
unite  to  form  the  genital  system  in  the  female. 

a.  Form. 

§ 2413.  It  is  pyriform,  and  much  more  extensive  from  above  down- 
ward than  from  right  to  left.  Its  thickness  is  much  less  than  its 
breadth.  Its  upper  and  largest  part,  which  is  termed  the  body , is  tri- 
angular. It  gradually  contracts  toward  the  base.  The  lateral  edges 
are  straight,  the  upper  is  very  convex. 

The  upper  part  of  the  body  is  called  the  base  ( fundus  uteri).  The 
inferior,  termed  the  neck  ( collum , s.  cervix  uteri)  is  nearly  cylindrical. 

The  anterior  and  posterior  faces  of  the  uterus  are  very  convex,  the 
second  more  so  than  the  first,  so  that  particularly  in  the  early  periods 
of  life,  we  may  admit  two  posterior  lateral  faces,  which  unite  at  an 
obtuse  angle  on  the  median  line. 

The  uterus  represents  a cavity  closed  at  its  upper  part,  always  ex- 
cepting the  narrow  orifices  of  the  two  Fallopian  tubes,  but  open  below 
and  continuous  in  this  direction  with  the  vagina. 

§ 2414.  The  parietes  of  this  organ  are  very  thick,  firm  and  solid, 
in  the  perfect  state.  The  middle  region  of  its  body,  its  thickest  portion, 

(1)  J.  A.  Pratis,  Libri  duo  de  uteris,  Antwerp,  1524.— -L.  Bonaccioli,  De  uteri 
sections,  Strasburg-,  1529. — M.  A.  Ulmus,  Uterus  muliebris,  Bologna,  1601. — J. 
Swammerdam,  Miraculum  naturce  de  uteri  muliebris  fabricâ,  Leyden,  1672. — C. 
Drelincourt,  De  utero,  Leyden,  1682. — M.  B.  Valentini,  De  novâ  matricis  anatome, 
Giessen,  1683. — G.  Bartholin,  De  utero,  Leyden,  1684. — A.  Nuck,  Adenographia 
curiosaet  uteri  Jeminei  anatome  nova,  Leyden,  1692. — F.  Ruysch,  'J'ractatus  de 
musculo  in  fundo  uteri  observato,  antea  a nemine  detecto,  Amsterdam,  1726.— A. 
Vater,  De  musculo  novo  uteri,  Amsterdam,  1727. — J.  J.  Huber,  Uteri  muliebris  par- 
tiumque  ad  earn  facientium  preecipuarum  iterata  explicatio  ; Halleri  leones , fase.  I. 
— I.  U.  Buchwald,  De  musculo  Ruyschii  in  fundo  uteri,  Copenhagen,  1741. — J. 
Weitbrecht,  De  utero  muliebri  observationes  ; in  N.  C.  Petrop,  vol.  i.  p.  337. — Sue, 
Recherches  sur  la  matrice  ; in  the  Mém.  pres.,  vol.  v. — J.  G.  Rœderer,  leones  uteri 
humani  observationibus  illustralœ,  Gottingen,  1759. — T.  Simson,  Observations  con- 
cerning the  placenta,  the  two  cavities  of  the  uterus , and  Ruysch' s muscle  in  fundo 
uteri  ; in  the  Edinb.  med.  essays,  vol.  iv.  n.  13. — J.  G.  Walter,  Betrachtungen  über 
die  Geburtstheile  des  weiblichen  Geschlechtes,  Berlin,  1776.— J.  C.  Loder,  Demuscu- 
losà  uteri  structuré,  Jena,  1782. — J.  G.  Weisse,  De  structura  uteri  non  musculosa 
sed  celluloso-vasculosa,  Wirtemberg,  1784. — G.  Azzoguidi,  Observationes  ad  uteri 
constructionem  pertinentes,  Leyden,  1788.— O.  F.  Rosenberger,  De  viribus  partum 
efficientibus  generatim  et  de  utero  speciatim,  ratione  substantive  musculosce  et  va- 
sorum  arteriosorum,  Halle,  1791. — C.  H.  Ribke,  Ueber  die  Structur  der  Gebärmut- 
ter, Berlin,  1793. — G.  C.  Titius,  De  uteri  structura  ex  ejusdem functionibus,  Wir- 
temberg, 1795. — J.  F.  Lobstein,  Fragment  d'anatomie  physiologique  sur  l'organi- 
sation de  la  matrice,  Paris,  1803. — J.  U.  G.  Joerg,  Ueber  das  Gebarorgan  des  Mens- 
chen und  der  tSàugthiere  im  schwängern  und  nicht  schwängern  Zustande , Leipsic, 
1808. — C.  Bell,  On  the  muscularity  of  the  uterus  ; in  the  Med.  chir.  trans.,  vol.  iv. 
1813,  p.  335. — J.  B.  Belloni,  Memoria  sopra  la  vera  struttura  deliutero,  Rovigo,  1821. 
— Mad.  Boivin,  Mémorial  de  l'art  des  accouchemens , Paris,  1824,  p 57. 


OF  THE  GENITAL  SYSTEM. 


401 


is  half  an  inch  thick.  The  body  is  a little  thicker,  but  perhaps  a little 
softer  than  the  neck. 

The  anterior  and  posterior  parietes  gradually  grow  thin  on  the  out- 
side, and  the  internal  upward,  so  that  their  thickness  diminishes  from 
four  or  five  lines  to  one,  and  thus  resembles  that  of  the  tubes,  which 
proceed  some  lines  in  the  substance  of  the  organ,  following  an  oblique 
direction  from  above  downward,  and  from  without  inward. 

The  form  of  the  cavity  of  the  uterus  generally  corresponds  with  its 
external  figure,  although  it  is  extremely  narrow  in  regard  to  the 
thickness  of  the  parietes,  whence  it  follows,  that  its  anterior  and  pos- 
terior faces  almost  touch.  Its  mean  breadth  does  not  exceed  four 
lines.  The  three  edges  of  the  body  are  concave  outward  and  convex 
inward,  while  externally,  only  the  upper  edge  of  the  uterus  is  convex 
outward.  The  cavity  of  the  neck  is  circumscribed  by  faces  convex 
outward,  while  its  outer  face  is  concave,  as  the  organ  is  con 
traded  a little  on  its  centre.  The  form  of  the  cavity  also  differs  from 
that  of  the  outer  circumference,  in  this  respect,  that  it  extends  above 
on  each  side  into  a long  horn,  which  gradually  contracts,  and  at  the 
summit  of  which  the  Fallopian  tube  opens. 

The  cavity  is  narrowest  in  the  neck,  particularly  on  the  limit  be- 
tween the  neck  and  the  body,  where  it  contracts  very  much.  It  is 
termed  in  this  place  the  upper  or  internal  orifice  of  the  uterus  ( ostium 
uteri  internum ). 

Thence,  the  neck  enlarges  to  about  it's  centre,  and  then  again,  con- 
tracts. It  terminates  below  in  the  upper  extremity  of  the  vagina,  by 
two  sacs,  an  anterior  and  a posterior,  the  latter  of  which  is  usually 
longer,  but  the  anterior  descends  a little  lower,  and  between  which  we 
usually  observe  a transverse  fissure,  more  rarely  a smaller  rounded 
opening,  termed  the  os  tincæ , the  external  or  vaginal  orifice  of  the 
uterus  ( orificium  uteri  externum , os  uterinum).  The  two  sacs  are 
termed  the  lips  (labia)  of  this  orifice. 

The  inner  face  of  the  uterus  is  smooth  in  the  body,  but  corrugated 
in  the  neck,  along  the  anterior  and  posterior  parietes  of  which  is  a lon- 
gitudinal prominence,  which  gradually  diminishes  from  above  down- 
ward, the  sides  of  which  present  oblique  bands,  which  render  it  very 
uneven.  On  the  sides  between  the  two  prominences  we  observe  also 
numerous  elevations,  which  intercross  like  a net-work.  The  lips  of 
the  os  tincæ  are  smooth,  at  least  if  we  except  lacerations,  which  are 
always  accidental,  and  occur  rather  frequently  during  parturition. 

b.  Volume. 

§ 2415.  In  virgins  the  uterus  is  about  two  inches  long,  nearly  half 
of  which  is  formed  by  the  neck.  The  greatest  breadth  of  the  body  is 
sixteen  lines,  and  that  of  the  neck  from  nine  to  ten.  The  lips  of  the 
os  tincæ  are  about  ten  lines  broad,  and  the  breadth  of  the  external  ori- 
fice of  the  uterus  is  about  six. 


402 


DESCRIPTIVE  ANATOMY. 


The  vaginal  portion  of  the  uterus  is  about  six  lines  thick,  and  the 
fissure  is  very  narrow  in  this  direction. 

In  females  who  have  borne  children  the  uterus  commonly  never 
returns  to  its  primitive  dimensions,  and  the  orifice  of  the  os  tincæ  also 
appears  a little  broader  from  before  backward. 

c.  Weight. 

§ 2416.  The  well  developed  uterus  of  a virgin  weighs  between 
seven  and  eight  drachms  ; but  in  a female  who  has  borne  children, 
and  in  whom  the  uterus  has  contracted  as  much  as  possible,  it  often 
weighs  an  ounce  and  a half. 

d.  Situation. 

§ 2417.  The  uterus  is  situated  between  the  bladder  and  rectum. 
Its  upper  half  is  placed  in  the  cavity  of  the  peritoneum,  a fold  of 
which  is  intimately  attached  to  its  surface. 

In  the  perfect  state  it.  is  situated  entirely  in  the  small  pelvis,  and  its 
base  rises  only  to  the  level  of  the  upper  edge  of  the  symphysis  pubis. 
This  part  is  directed  forward  and  upward:  the  os  tincæ,  on  the  con- 
trary, downward  and  backward,  so  that  the  longitudinal  diameter  of 
the  axis  of  the  organ  corresponds  nearly  to  the  upper  axis  of  the  pelvis, 
and  it  cuts  the  axis  of  the  body  backward  and  downward. 

e.  Attachments. 

§ 2418.  The  uterus  is  attached  to  the  adjacent  parts  by  several  folds 
of  peritoneum,(l)  which  are  continuous  with  the  serous  tunic  of  its 
body,  from  whence  they  arise  inward. 

The  largest  are  the  lateral  or  broad  ligaments  (/.  uteri  lateralia,  s. 
lata).  They  pass  from  the  lateral  edges  of  the  uterus,  receive  the  ves- 
sels of  this  organ  between  their  anterior  and  posterior  layers,  go  trans- 
versely outward  toward  the  circumference  of  the  pelvis,  divide  this 
cavity  into  two  halves,  an  anterior  and  a posterior,  the  first  of  which 
is  smaller  than  the  second,  and  are  continuous  with  the  lateral  wall  of 
the  peritoneum. 

Beside  these  vessels,  this  fold  of  the  peritoneum  possesses  more  or 
less  distinct  transverse  muscular  fibres,  which  leave  the  lateral  edge 
of  the  uterus  and  gradually  terminate  on  the  outside. (2) 

(1)  J.  C.  Schützer,  De  Jabricâ  et  morbis  ligamentum  uteri , Harderwyck,  1729. — 
A.  Petit,  Description  anatomique  de  deux  ligamens  de  la  -matrice  nouvellement  ob- 
servés-, in  the  Mêm.  de  Paris,  1760.— A.  Portai,  Observ.  sur  la  structure  des  parties 
de  la  génération  de  la  femme  ; in  the  Mém.  de  Paris,  1770,  p.  183. 

(3)  Sue,  Recherches  sur  la  matrice  ; in  the  Mém.  prés.,  vol.  v.,  p.  248. 


or  THE  GENITAL  SYSTEM. 


403 


Another  fold,  which  is  much  smaller,  elongated,  and  rounded,  forms 
on  each  side  the  posterior  inferior  ligament,  or  the  semilunar  fold  of 
Douglas  (l.  uteri  inferius  posterius,  s.  plica  semilunaris  Douglasii), 
which  extends  from  before  backward  from  the  lower  part  of  the  poste- 
rior face  of  the  uterus  to  the  rectum. 

This  ligament  also  contains  longitudinal  muscular  fibres.(l) 

A third,  which  is  still  smaller,  the  inferior  anterior  ligament  (l.  uteri 
inferius  anterius ),  one  of  which  generally  exists  on  each  side,  extends 
from  behind  forward  from  the  lower  part  of  the  anterior  face  of  the 
uterus  to  the  bladder,  embraces  this  latter,  and  frequently  also  pos- 
sesses muscular  fibres. 

Finally  we  find  on  each  side  a very  long  and  rounded  ligament, 
which  leaves  the  upper  part  of  the  lateral  edge  of  the  uterus,  directly 
below  and  before  .the  inner  extremity  of  the  Fallopian  tube;  it  is 
termed  the  round  ligament  (/.  uteri  rotundum , s.  teres).  This  ligament 
is  first  situated  between  the  two  layers  of  the  broad  ligament,  passes 
behind  the  umbilical  artery  and  before  the  hypogastric  vessels,  is  di- 
rected from  below  upward  and  from  within  outward  directly  behind 
the  peritoneum,  towards  the  upper  and  external  orifice  of  the  inguinal 
canal,  is  reflected  in  this  place  on  the  epigastric  artery,  then  enters  the 
inguinal  canal,  proceeds  from  above  downward,  from  without  inward, 
and  from  behind  forward,  emerges  from  the  inguinal  canal  thiough  the 
inguinal  ring,  and  terminates  by  dividing  into  several  fasciculi  in  the 
fat  of  the  mons  veneris,  and  in  the  upper  part  of  the  external  labia. 

It  is  composed  principally  of  cellular  tissue  and  vessels,  but  it  pos- 
sesses also  some  very  distinct  longitudinal  muscular  fibres,  the  upper 
of  which  arise  from  the  external  layer  of  the  fibres  of  the  uterus,  while 
the  lower  come  from  the  lower  edge  of  the  two  internal  broad  muscles 
of  the  abdomen,  which  are  directed  from  below  upward. 

These  ligaments  keep  the  uterus  in  place.  The  muscular  fibres  of 
the  broad  ligament  serve  also  to  approximate  the  Fallopian  tubes  to 
the  ovaries. 

When  the  fibres  of  the  broad  and  round  ligaments  of  one  side  act 
more  forcibly  than  those  of  the  opposite  side,  the  uterus  is  carried  tran- 
siently or  permanently  into  one  half  of  the  pelvis,  an  arrangement 
which  we  have  often  observed,  al’hough  it  depended  on  no  mechanical 
cause,  and  although  the  parts  which  serve  to  retain  the  uterus  were 
unaltered  in  their  texture. 


f.  Texture. 

§ 2419.  At  first  view  the  tissue  of  the  uterus  seems  to  be  homoge- 
neous ; we  however  distinguish  in  it  when  unimpregnated,  several 
layers  superimposed  from  behind  forward,  which  have  a reddish  yellow 
color,  and  between  which  are  whitish  bands. 


(1)  Sue,  ibid. 


404 


DESCRIPTIVE  ANATOMY. 


The  vessels  of  the  uterus,  which  are  very  tortuous  and  frequently 
anastomose  together,  proceed  between  these  layers  both  on  the  ante- 
rior and  near  the  posterior  face. 

a.  Fibres. 

§ 2420.  There  is  perhaps  in  anatomy  no  subject  on  which  opinions 
are  more  divided  than  in  respect  to  the  fibres  of  the  uterus,  or,  to  state 
the  question  more  exactly,  in  regard  to  the  existence  of  these  fibres 
generally,  their  nature,  and  their  arrangement. 

1st.  Several  anatomists,  particularly  Walter,  Bcehrner,  Blumenbach, 
Azzoguidi,  and  Ribke,  formally  deny  their  existence,  which  is  ad- 
mitted, on  the  contrary,  by  Vesalius,  Piccolomini,  Malpighi,  Morgagni, 
Diemerbroek,  Verheyen,  Vieussens,  Ruysch,  Vater,  Santorini,  Buch- 
wald,  Weitbrecht,  Monro,  Noortwyk,  Heister,  Haller,  Sue,  Astruc, 
Levret,  Rœderer,  Meckel,  Hunter,  Wrisberg,  Loder,  Mayer,  Simeon, 
Calza,  Lobstein,  and  Bell. 

Thus  the  second  opinion,  which  we.  also  have  adopted,  is  supported 
by  most  authorities. 

But  the  anatomists  who  admit  their  existence  differ  ; some  consider 
the  fibrous  texture  of  the  uterus  as  constantly  existing;  while  others, 
who  are  more  numerous,  think  that  these  fibres  exist  only  in  certain 
conditions,  as  in  gestation. 

It  is  a fact  that  these  fibres  are  at  least  very  slightly  apparent,  ex- 
cept in  pregnancy.  They  however  do  not  form  only  during  this  state, 
but  whenever  the  formative  power  of  the  uterus  is  exalted.  Lobstein 
has  found  them  very  apparent  in  a female  where  the  uterus  was  much 
distended  by  a steatomatous  tumor,  as  it  is  generally  in  the  seventh 
month  of  pregnancy.  He  attributes  this  phenomenon  to  the  distension 
caused  by  the  tumor  ; but  we  have  observed  them  more  or  less  evi- 
dently in  the  uterus  of  females  where  analogous  tumors  existed  in  the 
uterus  and  ovaries,  so  that  we  think  it  more  correct  to  admit  that  they 
depend  on  a change  of  the  proper  vitality  of  the  uterus. 

2d.  Most  anatomists  consider  these  fibres  as  muscular.  In  fact  they 
differ  from  the  red  fibres  which  form  the  voluntary  muscles,  as  they 
are  less  red,  flat,  and  strongly  united  with  each  other  ; but  their  mus- 
cular nature  is  proved  by  their  powerful  contraction,  either  during 
parturition  to  expel  the  fetus  and  the  secundines,  or  afterward,  to  con- 
tract the  uterus  and  almost  obliterate  its  cavity  very  rapidly. 

In  these  twm  characters  they  are  very  analogous  to  the  involuntary 
muscles. 

This  in  fact  is  the  manner  in  which  the  fibres  of  the  uterus  act,  and 
their  substance  presents  in  the  different  states  of  this  organ  the  different 
modifications  observed  in  the  muscular  system  of  organic  life,  that  is, 
when  the  uterus  is  unimpregnated,  they  resemble  the  fibres  of  the  ar- 
teries, and  during  gestation,  those  of  the  other  involuntary  muscles, 
except  the  heart. 


OF  THE  GENITAL  SYSTEM. 


405 


The  uterus  of  the  female  contains  also  a great  proportion  of  fibrine. 

Finally  we  may  also  mention  the  analogy  with  the  mammalia, 
where  the  uterus  is  evidently  muscular  at  all  periods  of  life,  adding 
however  that  by  a very  remarkable  arrangement,  the  fibres  in  the 
uterus  of  the  female  do  not  evidently  possess  this  character,  except 
when  the  formative  power  of  the  organ  is  increased. 

3d.  The  direction  of  the  fibres  is  not  described  in  the  same  manner 
by  all  anatomists.  Most  of  them,  however,  agree  that  they  possess  at 
least  two  directions,  a longitudinal  and  a transverse  ; so  that  in  this 
respect  also  they  resemble  the  muscles  of  organic  life. 

They  are  however  more  complex,  since  we  find  several  layers  pro- 
ceeding in  different  directions,  as  the  layers  composed  of  fibres  which 
have  the  same  direction  proceed  several  times  from  within  outward  ; 
and  as  finally  the  different  layers  frequently  interlace  together. 

Some  authors,  particularly  Malpighi  and  Monro(l)  maintain  that 
the  fibres  are  not  arranged  regularly. 

Ruysch  admits  only  a single,  unmated,  and  circular  muscle,  situated 
at  the  base  of  the  uterus.  Although  several  anatomists,  as  Vater, 
Monro,  and  Simson  agree  with  him,  it  is  however  certain  that  the 
arrangement  of  the  fibres  of  the  uterus  is  not  so  simple.  Farther  the 
description  Ruysch  has  given  of  this  muscle  is  not  perfectly  exact. 

The  following  are  the  most  general  characters  of  the  arrangement 
of  the  muscular  fibres  of  the  uterus  : 

1st.  There  are  two  layers,  an  external  and  an  internal,  which  are 
separated  by  the  vascular  substance  of  the  organ. 

2d.  The  different  planes  and  layers  are  interlaced  so  intimately  that 
it  is  difficult  to  separate  them. 

3d.  The  external  layer  is  much  thicker  than  the  internal. 

4th.  The  muscular  substance  is  much  thicker  at  the  upper  part  of 
the  uterus,  particularly  in  its  base,  than  in  the  other  regions.  It  does 
not  exist  at  all,  or  at  least  is  very  thin,  in  the  neck. (2) 

5th.  Generally  speaking  the  longitudinal  fibres  are  much  more 
numerous  than  the  others.  The  circular  fibres,  however,  are  more 
developed  at  the  base  of  the  organ,  while  the  longitudinal  fibres  are 
larger  near  the  lower  orifice. 

6th.  The  external  plane  is  composed  of  longitudinal  fibres,  which 
depart  from  the  centre  of  the  base,  are  distributed  from  above  down- 
ward on  the  anterior  and  posterior  faces,  follow  an  oblique  and  even 
transverse  direction,  and  disappear  toward  the  neck.  Some  of  these 
fibres  are  irregular,  others  are  continuous  with  the  round  ligaments. 

7th.  According  to  some  authors,  Rosenberger  for  instance,  the  ex- 
ternal plane  is  composed  only  of  longitudinal  fibres  ; there  are  however 
below  these  fibres  other  transverse  fibres  which  also  go  to  the  round 
ligaments  and  to  the  Fallopian  tubes. 

(1)  Dissection  of  a woman  with  child,  with  remarks  on  the  gravid  uterus  ; in  the 
Edinb.  phys.  and  Med.  Essays,  vol.  i.,  p.  459  and  470. 

(2)  Beil,  loc.  cit.,  p.  342. 

VOL.  III. 


52 


406 


DESCRIPTIVE  AH  ATOM  ï\ 


8th.  We  also  remark  in  this  plane,  oblique  fibres  which  have  very 
different  directions,  and  are  tortuous  ; these  interrupt  particularly  the 
longitudinal  layers,  and  occur  principally  at  the  lower  part  of  the 
body. 

9th.  The  oblique  fibres  do  not  exist  in  the  neck,  which  however  is 
composed,  at  least  frequently,  of  several  superimposed  layers  of  trans- 
verse and  longitudinal  fibres. 

10th.  The  inner  plane,  which  is  the  thinnest,  is  formed  of  two 
layers.  The  external  is  composed  of  two  circular  muscles,  each  si- 
tuated round  one  of  the  orifices  of  the  tubes  ; they  blend  together  on 
the  median  line  anteriorly  and  posteriorly,  by  the  inner  part  of  their 
edge.  Very  probably  one  of  these  circular  layers  is  the  muscle  of 
Ruysch,  who  had  considered  the  lateral  wall  of  the  uterus  as  the 
upper,  and  had  neglected  the  opening  of  the  tube. 

11th.  Below  this  layer  are  longitudinal  and  oblique  fibres,  which 
unite  on  each  side  anteriorly  and  posteriorly  to  form  two  elongated 
triangles,  the  summits  of  which  blend  in  the  orifice  of  the  tube. 

12th.  Below  these  fibres,  and  interlacing  with  them,  are  rather 
transverse  and  indistinct  fibres,  seen  particularly  at  the  lower  part  of 
the  uterus.(l) 

(1)  Mad.  Boivin  describes  the  fibres  of  the  uterus  differently.  She  remarks  that 
after  macerating  the  uterus  for  a few  days,  wo  observe  on  each  face  six  fibrous  fasci- 
culi, three  on  the  right  and  three  on  the  left  of  cacti  wall,  besides  one  which  is  ver- 
tical, and  which  forms  the  median  line.  This  last  layer,  which  extends  from  the 
circumference  of  the  base  to  the  base  of  the  body,  presents  longitudinal  fibres.  Each 
of  the  others  seems  to  arise  from  the  median  line  : 1st,  at  the  centre  of  the  base  are 
two  fasciculi,  one  on  each  side,  which  extend  transversely  on  the  edge  of  the  base  to 
the  upper  angles,  where  they  fold  in  the  form  of  tubes,  which  separate  and  extend  to 
form  the  tubes  ; 2d,  below  this  first  layer  of  the  anterior  face,  two  other  broader 
layers,  which  occupy  the  upper  half  of  the  body,  proceed  horizontally  on  each  side 
from  the  median  line,  and  a little  before  the  angle  of  the  tube,  to  unite  to  other  layers 
of  fibres,  and  there  form  the  origin  of  the  round  ligament  ; 3d,  at  the  lower  third  of 
the  median  line  two  other  layers  of  fibres  are  directed  obliquely  from  below  upward, 
separating  on  the  sides  : one  portion  of  this  fasciculus  unites  to  the  band  of  fibres  of 
the  round  ligaments,  and  the  other  blends  and  interlaces  with  the  transverse  fibres 
of  the  posterior  regions  of  the  organ.  On  the  posterior  wall  of  the  uterus  the  ar- 
rangement of  the  fibrous  layers  is  nearly  the  same  as  in  the  anterior  wall.  The 
middle  layer  is  more  prominent  than  that  of  the  anterior  face,  and  also  presents  lon- 
gitudinal fibres.  The  fibrous  layers  of  the  upper  region  extend  across,  leaving  the 
median  line,  to  the  origin  of  the  tubes  and  a little  below,  where  they  unite  to  go  to 
the  ovaries,  of  which  they  form  the  ligament.  Below  is  another  layer,  which  reas- 
cends obliquely  and  divides  rather  distant  from  their  point  of  departure  into  two 
portions  : one  superior  and  lateral,  turns  on  the  side,  and  goes  to  unite  forward  to 
the  round  ligaments  ; the  other  terminates  in  the  form  of  a ring,  and  goes  to  the 
base  of  the  ovary.  At  the  lower  extremity  of  the  median  line  in  the  external  central 
region  of  the  neck  arc  two  other  fasciculi,  which  are  composed  of  a portion  of  the 
fibres  of  the  median  line  of  the  neck,  separate  some  lines  from  each  other,  are  insu- 
lated, and  arc  attached  to  the  lateral  edges  of  the  middle  region  of  the  3acrum,  and 
form  the  posterior  ligaments. 

These  different  fibrous  layers  change  their  direction  during  pregnancy.  In  pro- 
portion as  the  body  of  the  uterus  elongates  and  enlarges,  the  layers  of  fibres  of  the 
upper  regions  from  transverse  become  oblique,  their  median  extremities  rise  to- 
wards the  middle  of  the  base,  and  their  lateral  extremities  are  depressed,  in  the  same 
proportion,  to  the  lower  third  of  the  lateral  edges  of  the  organ,  so  that  at  the  end  of 
gestation  the  fibrous  layers  of  the  upper  and  lateral  regions  have  a radiated  arrange- 


OF  THE  GENITAI.  SYSTEM. 


407 


b.  Internal  surface. 

§ 2421.  The  inner  surface  of  the  uterus  is  covered  by  a reddish  mu- 
cous membrane,  which  is  almost  smooth,  and  presents  only  some  very 
small  villosities,  which  are  continuous  above  and  on  each  side  with 
those  of  the  tubes,  and  below  with  that  of  the  vagina. 

In  the  recent  state  this  membrane  adheres  so  intimately  to  the  sub- 
jacent fibrous  substance  that  it  is  inseparable,  although  its  structure 
intimates  distinctly  that  it  belongs  to  the  class  of  mucous  membranes  ; 
but  after  macerating  the  uterus  we  can  detach  some  folds  of  it  by  care 
and  precaution. 

Its  intimate  union  with  the  rest  of  the  substance  of  the  uterus  has 
caused  its  existence  to  be  doubted  by  several  anatomists.(l) 

We  find  some  muciparous  glands  only  in  the  neck,  particularly  at 
its  lower  part.  Not  unfrequently  their  orifice  is  obliterated,  perhaps 
from  inflammation.  They  then  form  more  or  less  numerous  large 
cysts  filled  with  a limpid  liquid,  produced  by  the  accumulation  of  their 
habitual  secretion. 

These  cysts  are  termed  the  ovula  of  JYaboth  (ovula  JYabothiana,  s. 
ovarium  secundarium),(2 ) which  have  been  very  badly  compared  to 
the  ovula  of  Graaf. 


iment,  and  may  be  compared  to  a head  with  Ions'  hair,  separated  in  all  the  extent  of 
the  median  line  of  the  skull,  smooth  on  each  side  of  the  forehead,  and  situated  very 
near  and  before  each  ear  : this  union  in  a single  fasciculus  of  these  superior  fibrous 
layers  forms  forward  and  on  each  side  the  broad  ligaments.  The  layers  of  fibres  of 
the  lowerVegion  of  the  body  have  löst  progressively  the  oblique  direction  assumed 
by  them  at  first,  and  become  semicircular.  These  fibrous  layers,  which  leave  the 
lower  portion  of  the  median  line,  unite  on  the  sides  and  before  the  middle  region  of 
the  uterus  to  the  broad  ligaments,  an  inch  below  the  union  of  the  superior  fasciculi. 
The  direction  of  the  fibrous  layers  of  the  posterior  wall  is  changed  in  nearly  the 
same  manner  as  those  of  the  anterior  face.  These  layers,  which  are  at  first  trans- 
verse, are  arranged  obliquely  from  above  downward,  and  turn  on  each  side.  One 
portion  is  attached  to  the  ovary,  and  then  projects  on  the  lateral  face  of  the  uterus, 
and  the  other  passes  below  these  glands  to  unite  forward  to  the  anterior  fasciculi 
which  form  the  round  ligaments,  whence  it  follows  that  not  only  the  fibrous  layers 
of  the  anterior  region  of  the  uterus,  but  also  a portion  of  the  middle  layers  of  the 
posterior  region,  contribute  to  form  these  ligaments.  The  median  layers,  which  are 
arranged  longitudinally,  extend  from  the  base  to  the  origin  of  the  internal  orifice  of 
the  neck,  loose  their  vertical  direction  by  separating  progressively  on  the  sides,  and 
appear  at  the  end  of  gestation  a kind  of  tissue  of  fibres,  which  intercross,  and  from 
whence  proceed  the  other  layers  of  fibres  which  have  been  described  ( Mémorial  de 
l'art  des  accouchemens , Paris,  1824).  P.  T. 

(1)  This  is  the  opinion  of  Cbaussier  and  Ribes.  Mad.  Boivin  says  also  she  has 

never  seen  this  mucous  membrane,  and  thinks  that  the  inner  face  of  the  uterus  is 
formed  only  by  the  extremities  of  the  exhalent  vessels  which  open  there.  ( Mèmoria . 
des  accouchemens,  p.  66.)  This  explanation  is  very  vague,  if  not  unintelligible.  Ana- 
logy does  not  admit  us  to  doubt  that  the  inner  face  of  the  uterus  is  covered  by  a 
membrane.  F.  T. 

(2)  M.  Naboth,  De  sterililate  viutierum,  Leipsic,  1707. 


408 


DESCttlTTIVE  ANATOMY 


II.  ORGANS  OF  COPULATION. 

§ 2422.  The  organs  of  copulation  are  composed,  in  the  female,  of 
the  vagina,  the  clitoris,  the  external  labia,  and  the  nymphæ  ; the  three 
latter  have  been  termed  the  external  genital  parts  ( pudendum , s. 
cunnus),  in  opposition  to  the  others,  termed  the  internal. 

A.  VAGINA. 

a.  Form  and  dimensions. 

§ 2423.  The  vagina  is  a membranous  canal,  with  thin  parietes,  ge- 
nerally about  four  inches  long  and  one  broad,  and  larger  at  its  upper 
than  at  its  lower  part  ; it  is  directly  continuous  with  the  uterus. 

Its  upper  extremity  terminates  in  a cul-de-sac,  called  the  base  {fun- 
dus vaginae ),  and  is  continuous  with  the  substance  of  the  uterus,  em- 
bracing its  lower  or  vaginal  portion. 

The  other  extremity  is  narrower,  and  is  termed  the  entrance  of  the 
vagina  ( adilus  vagina, ) : it  opens  externally  where  it  is  continuous 
with  the  external  labia. 


b.  Situation  and  direction. 

§ 2424.  This  canal  is  situated  between  the  rectum,  the  bladder,  and 
the  urethra,  to  which  parts  it  is  united  by  very  loose  cellular  tissue. 
It  has  not  the  same  direction  as  the  uterus,  for  it  descends  from  behind 
forward,  so  that  its  axis  corresponds  exactly  to  the  lower  axis  of  the 
pelvis. 

Farther,  its  posterior  wall  is  slightly  convex,  and  the  anterior  is 
concave. 


c.  Texture. 

§ 2425.  The  vagina  is  formed  of  two  layers,  one  external,  very  thin, 
solid,  and  reddish  white,  which  corresponds  to  the  muscular  and  vas- 
cular tunics,  is  continuous  with  the  fibrous  tissue  of  the  uterus,  and 
gradually  becomes  more  solid  and  vascular  from  without  inward  ; the 
internal  is  reddish,  and  is  firmly  united  to  the  preceding,  from  which 
however  it  may  be  separated. 

It  is  very  much  corrugated  in  a full  grown  female,  and  particularly 
in  virgins. 

Among  these  folds  we  see,  particularly  on  the  anterior  and  posterior 
faces,  a series  which  is  transverse  and  oblique,  situated  one  above 
another  ( columna  rugarum  anterior  et  posterior),  which  are  the  conti- 


OF  THE  GENITAL  SYSTEM. 


409 


nuation  of  those  in  the  neck  of  the  uterus,  where  they  are  termed  the 
arbor  vitœ. 

There  are  some  muciparous  glands  at  the  upper  part  of  the  vagina. 

B.  HYMEN. 

§ 2426.  The  hymen  {hymen,  s.  valvula  vaginœ){  1)  is  a semicircular 
fold  of  the  mucous  membrane  of  the  genital  parts,  formed  of  tw'o  layers 
united  by  cellular  tissue  ; it  occupies  the  sides  and  the  posterior  part 
of  the  entrance  of  the  vagina,  and  leaves  a greater  or  less  space  be- 
tween its  anterior  concave  edge  and  the  anterior  part  of  the  vagina. 

Not  unfrequently  this  fold  arises  from  all  the  edge  of  the  canal. 
Even  then  however  the  opening  is  generally  situated  forward  and 
rarely  in  the  centre  ; the  hymen  is  rarely  also  thick,  hard,  solid,  and 
muscular. 

This  membrane  separates  the  internal  and  the  external  genital  or- 
gans, and  also  the  genital  and  the  urinary  systems,  as  we  perceive 
before  it  the  orifice  of  the  urethra,  surrounded  by  small  similar  folds. 

C.  CLITORIS. 

a.  Clitoris  in  itself.  • 

§ 2427.  The  clitoris  ( clitoris , s.  membrum  muliebre , s.  coles  femina- 
rum,  s.  nympha){2)  is  an  oblong,  rounded  body,  situated  below  the 
symphysis  pubis.  It  arises  from  the  upper  part  of  the  inner  face  of  the 
ascending  ramus  of  the  ischium  by  two  branches  about  an  inch  long, 
which  unite  at  an  obtuse  angle. 

It  terminates  forward  by  a small  elongated  and  rounded  prominence, 
called  the  glans  of  the  clitoris  ( G.  clitoridis).  This  enlargement  is 
covered  by  a thin  mucous  membrane,  and  by  a thick  and  soft  epider- 
mis, which  is  easily  detached,  and  it  is  surrounded  by  a triangular  fold 
of  skin  which  entirely  envelops  it. 

This  fold  of  skin,  termed  the  prepuce  of  the  clitoris  ( prœputium  cli- 
toridis), which  is  closed  above  and  open  or  cleft  below,  is  thin,  soft, 
and  moist  on  its  two  faces,  but  particularly  on  the  internal.  We  re- 
mark  in  it,  especially  where  the  prepuce  is  continuous  with  the  skin 
which  surrounds  the  glans  of  the  clitoris,  a great  number  of  sebaceous 
glands. 


(1)  A.  Vater,  De  hymene,  Wittemberg,  1727. — J.  J.  Huber,  De  hymene  et  raginm 
rugis,  Leyden,  1742. — B.  S.  Albinus,  De  hymene  ; in  the  Annot.  acad.,  Leyden,  1758, 
1.  iv.,  x. — Goering,  De  hymene , Altdorf,  1765.— G.  Tolberg,  De.  varietate  hymenum, 
Halle,  1791.— B.  F.  Osiander,  Abhandlung  über  die  Scheidenklappe  ; in  his  Denkwür 
digkeitenfür  die  Geburtshülfe,  vol.  ii.,  pt.  i.,  p.  1. 

(2)  T.  Tronchin,  De  nymphâ , Leyden,  1730. 


410 


DESCRIPTIVE  ANATOMY. 


On  a more  attentive  examination  we  remark  that  the  glans  is  not  a 
continuation  of  the  substance  of  the  posterior  part  of  the  clitoris,  but  is 
attached  to  it  only  by  cellular  tissue,  vessels,  and  nerves,  and  that  the 
posterior  part  of  the  clitoris  terminates  by  a concave  surface  destined 
only  to  support  it. 

§ 2428.  The  clitoris  is  composed  of  an  external  fibrous  sheath,  below 
which  is  a spungy  tissue  formed  by  broad  venous  trunks,  which  fre- 
quently anastomose.  Thus  these  lateral  parts  are  termed  the  cavernous 
bodies  ( C . cavernosa , s.  spongiosa  clitoridis ). 

After  the  two  branches  by  which  it  arises  unite,  we  observe  between 
its  two  lateral  halves  a perpendicular  fibrous  septum,  which  separates 
them  imperfectly,  and  which  is  directly  continuous  with  the  external 
envelop. 

There  is  no  trace  of  a septum  in  the  glans,  which  is  formed  of  a 
similar  but  finer  tissue. 

By  reason  of  this  texture  the  clitoris  is  capable  of  enlarging  very 
much. 

Its  vessels  and  nerves  proceed  on  its  dorsal  face,  which  are  very 
considerable  ; they  are  numerous  and  enter,  particularly  the  latter,  into 
the  glans. 

b.  Igchio-cavernoaus  muscle. 

§ 2429.  The  branches  of  the  clitoris  are  covered  at  the  lower  part 
of  their  edge  and  on  each  side  by  a muscle,  which  arises  directly  below 
their  lower  extremity  by  short  tendinous  fibres  ; these  are  attached  to 
the  inner  branch  of  the  ascending  ramus  of  the  ischium,  and  extend 
almost  to  their  other  extremity.  This  muscle  is  called  the  ischio-ca- 
vernosus  muscle  (JM.  ischio-cavernosus,  s.  director , s.  depressor  cli- 
toridis) . 

It  depresses  the  clitoris,  and  may  contribute  to  expel  the  blood  which 
collects  in  it  during  erection. 

D.  NYMPHJE, 

§ 2430.  The  small  or  internal  labia , or  the  nymphœ  ( L . pudendi 
internez , s.  minores , s.  nymphœ),  are  two  oblong,  reddish,  corrugated 
folds,  similar  to  the  crest  of  a cock,  and  very  much  compressed  from 
right  to  left  ; they  are  connected  posteriorly,  and  their  anterior  extremi- 
ties unite  in  the  glans  of  the  clitoris.  The  skin  which  covers  them  is  very 
delicate,  soft,  moist,  destitute  of  hair,  and  similar,  especially  on  its  inner- 
side,  to  a mucous  membrane. 

Their  inner  face  is  continuous  with  the  vagina,  and  the  external 
with  the  external  labia. 

They  are  formed  by  a spungy  tissue,  called  the  cavernous  body  of 
the  nymphœ  and  glans  ( corpus  cavernosum  nympharum  et  glandis), 


OF  THE  GENITAL  SYSTEM. 


411 


which  is  finer  than  that  of  the  clitoris,  but  is  similar  to  that  of  the 
glans,  of  which  it  is  the  direct  continuation. 

The  two  branches  of  the  prepuce  terminate  near  the  anterior  and 
upper  extremity  of  these  folds,  and  are  continuous  on  the  outside  with 
them. 

Hence  it  follows  that  the  nymphæ  divide  at  their  anterior  extremity 
into  two  branches  ; the  internal,  which  is  the  smaller,  enters  into  the 
glans,  and  the  external,  or  the  larger,  terminates  in  the  prepuce,  and 
their  spungy  tissue  unites  with  that  of  the  glans. 

The  space  between  them  is  termed  the  vestibule  ( vestibuhm ). 

E.  EXTERNAL  LABIA. 

§ 2431.  The  great  or  external  labia  ( L . pudendi  externa , s.  magna ) 
are  considerable  folds  of  skin,  directed  from  before  backward,  which 
envelop  the  other  external  genital  parts.  Their  external  fold  is  formed 
by  the  skin  : the  internal  by  a very  thin  mucous  membrane,  which  is 
continuous  with  that  of  the  nymphæ. 

They  unite  anteriorly  and  posteriorly,  thus  forming  the  anterior  and 
posterior  commissures.  They  are  imperceptibly  continuous  forward 
with  the  mons  veneris.  They  are  united  posteriorly,  on  the  inside 
and  above  the  posterior  commissure,  by  a thin  and  transverse  fold, 
termed  their  frenum  ( frenulum  pudendi). 

The  space  between  the  frenum  and  the  posterior  commissure  is 
termed  the  navicidar  fossa  {fossa  navicularis). 

T.  MUCOUS  CRYPTS  OP  THE  EXTERNAL  GENITAL  PARTS. 

§ 2432.  The  external  genital  parts  are  provided  with  numerous 
large  mucous  crypts  ; they  abound  particularly  around  the  orifice  of 
the  urethra  and  the  entrance  of  the  vagina.  The  first  have  been 
termed  the  prostate  of  Bartholini  {prostata  Bartholiniana).{\) 

G.  CONSTRICTOR  VAGINÆ  MUSCLE. 

§ 2433.  The  upper  extremity  of  the  external  genital  organs  in  the 
female  is  surrounded  on  a level  with  the  nymphæ  by  a thin,  long, 
round,  and  muscular  layer,  which  blends  posteriorly  with  the  anterior 
extremity  of  the  sphincter  ani  externus  muscle,  and  is  attached  forward 
to  the  branches  and  the  body  of  the  clitoris.  This  is  the  constrictor 
vaginae  muscle  (JVf.  constrictor  cunni). 

This  muscle  powerfully  contributes  to  contract  the  entrance  of  the 
vagina. 


(1)  Bartholini,  De  ovariis,  p.  21. 


412 


DESCRIPTIVE  ANATOMY. 


III.  VESSELS  AND  NERVES. 

§ 2434.  The  female  genital  organs  receive  their  vessels  from  two 
sources,  principally  from  the  spermatic  arteries  and  the  branches  of 
the  hypogastiic  arteries  ; they  are  termed  the  uterine  and  vaginal  ar- 
teries, and  the  arteries  of  the  clitoris,  and  they  are  distributed  in  the 
parts  of  the  same  name.  Some  twigs  of  the  internal  pudic  artery  also 
go  into  the  external  labia. 

The  synonymous  veins  carry  the  blood  into  the  crural,  the  hypo- 
gastric, and  the  renal  veins. 

The  spermatic  vessels  form  around  the  ovaries  a very  complex 
plexus,  called  the  pampiniform  body  ( plexus  pampiniformis).  They 
anastomose  in  the  substance  of  the  uterus  not  only  those  of  one  side 
with  those  of  the  other,  but  those  of  the  upper  part  with  those  of  the 
lower. 

The  nerves  of  the  internal  genital  parts(l)  come  from  the  ganglion- 
nary  nerve,  and  those  of  the  external  from  the  iliac  plexus. 

IV.  PROPERTIES  AND  FUNCTIONS. 

§ 2435.  As  the  external  genital  parts  of  the  female  receive  a great 
number  of  nerves,  they  possess  an  extreme  sensibility,  which  does  not 
exist  to  the  same  degree  in  the  internal. 

The  uterus  by  its  muscular  fibres  possesses  great  powers  of  con- 
tractility, which  exist  to  a certain  degree  in  the  vagina  also. (2) 

The  formation  of  the  new  being  commences  in  the  ovary. (3) 

The  following  facts  prove  this  proposition  : 

1st.  When  extirpated,  sterility  ensues,  although  all  the  other  parts 
remain  perfect. 

2d.  Of  all  the  parts  of  the  genital  system  the  first  changes  after  a 
productive  copulation  are  observed  in  them. 

3d.  Fetuses  have  been  found  within  them. 

4th.  They  have  also  been  found  in  the  abdomen,  without  any  trace 
of  injury  in  the  parts,  and  with  or  without  the  closing  of  the  tubes. 

The  tubes  receive  the  product  of  conception  which  is  developed  in 
the  ovary,  and  carry  it  into  the  uterus.  This  is  proved  : 

(1)  F.  Tiedemann,  Tabules  nervorum  uteri,  Heidelberg-,  1822. 

(2)  Lobstein,  in  the  Journ.  de  médecine , vol.  xxxvi.,  p.  143. 

(â)  Prévost  and  Dumas  assert  (Mémoire  sur  la  génération  dans  les  mammifères 
et  les  premiers  indices  du  développement  de  l’embryon  ; in  the  Annales  des  sc.  nat,, 
vol.  iii.,  p.  134)  that  fecundation  does  not  take  place  in  the  ovary,  because  we  never 
find  in  the  pouch  covering  this  organ  the  spermatic  animalculæ,  which  are  consi- 
dered the  agents  of  fecundation;  so  that  according  to  them  the  moment  of  fecun- 
dation is  much  later  than  that  of  copulation,  and  the  ovum  is  not  impregnated  until 
arriving  in  the  Fallopian  tube  or  the  uterus  it  comes  in  contact  with  the  seminal 
fluid.  How  can  this  theory  be  reconciled  with  ovarian  pregnancy  7 F.  T. 


OF  THE  GENITAL  SYSTEM. 


413 


1st.  By  the  fetuses  found  in  the  cavity  of  the  abdomen. 

2d.  By  those  found  within  the  tube,  especially  in  the  cases  where 
the  external  or  internal  orifice  of  this  passage  was  obliterated. 

3d.  The  uterus  is  the  organ  in  which  the  new  organism  is  deve- 
loped. 

This  proposition  is  supported  by  the  following  arguments; 

1st.  The  fetus  is  developed  in  the  uterus,  when  no  anomaly  occurs. 

2d.  Even  when  the  fetus  is  developed  out  of  the  uterus,  the  latter 
undergoes  the  usual  changes  in  its  substance  and  its  cavity.  The 
possibility  of  extra-uterine  fetation,  however,  proves  that  it  is  not  ab- 
solutely necessary  to  form  the  new  organism. 

The  vagina  is  only  the  conducting  organ  of  the  penis,  the  semen, 
and  the  fetus. 

The  external  parts  are  the  exciting  organs,  the  organs  of  pleasure, 
as  is  proved  by  their  increase  of  susceptibility  before  and  during 
coition. 

This  increase  of  susceptibility  communicated  to  the  internal  geni- 
tal organs  and  to  the  organism  is  attended  with  the  degree  of  energy 
or  excitement  necessary  to  produce  the  new  being. 

B.  GENITAL  ORGANS  OF  THE  MALE. 

■ I.  FORMATIVE  ORGANS. 

A.  TESTICLES. 

§ 2436.  The  most  important  genital  organs  in  the  male  are  the 
testicles  ( didymi , s.  testes , s.  testiculi)  ,(l)  or  the  glands  which  secrete 
the  semen. 

a.  Form  and  situation. 

§ 2437.  The  testicles  have  an  elongated,  rounded,  and  an  almost 
oval  form.  They  are  situated  at  the  lower  part  of  the  trunk,  on  the 
sides  and  below  the  penis,  in  a special  fold  of  the  skin  which  is  formed 
like  a sac,  and  is  termed  the  scrotum.  They  communicate  wfith  the 
parts  of  the  genital  apparatus  situated  within  the  abdomen,  by  the 
spermatic  cord  ( funiculus  speculations,  s.  testicularis).  This  cord  is 
formed  by  their  excretory  duct,  their  vessels  and  nerves,  and  the  cre- 
master muscle. 

(1)  R.  de  Graaf,  De  virorum  organis  generations  inservientibus,  Leyden,  1668. — 
Leal  Leali,  De  partibus  confie  ientibus  in  viro,  Padua,  1686. — Santorini,  De  virorum 
naturalibus  ; in  the  Obs.  anat .,  cap.  x. — J.  G.  Rœderer,  De  genitalibus  virorum, 
Gottingen,  1758. — J.  Wilson,  Lectures  on  the  structure  and  physiology  of  the  male 
urinary  and  genital  organs  of  the  human  body , London,  1821. 

Vol.  III.  53 


414 


DESClUfTIVE  ANATOMY. 


b.  Volume  and  weight. 

§ 2438.  The  testicle 'alone,  that  is  its  substance,  when  its  envelops, 
except  the  most  internal,  are  removed,  is  generally  an  inch  and  a half 
long,  one  broad,  and  about  nine  lines  thick. 

It  usually  weighs  about  four  drachms. 

c.  Composition, 
a.  Membranes. 

§ 2439.  The  testicles  are  surrounded  with  several  superimposed 
layers,  which  vary  in  their  nature,  and  are  termed  tunics. { 1) 

1.  Skin  of  the  scrotum. 

§ 2440.  The  external  layer  is  the  skin  of  the  scrotum,  a fold  of  the 
common  integuments,  which  descends  from  the  inguinal  region,  and 
terminates  between  the  roots  of  the  penis  and  the  perineum.  This 
fold,  which  is  broader  at  its  lower  than  at  its  upper  part,  differs  from 
the  rest  of  the  skin,  as  it  is  generally  a little  darker  colored,  since  it 
presents  distinct  hairs,  and  because  there  is  no  fat. 

It  presents  also  exactly  on  the  median  line  a narrow  sac,  the  direc- 
tion of  which  is  from  before  backward  ; this  is  slightly  prominent,  and 
is  formed  by  numerous  transverse  folds  arranged  very  compactly,  and 
is  termed  the  raphe.  Although  apparently  thicker  at  this  part,  the 
scrotum  is  in  fact  thinner  than  in  any  other. 

The  epidermis  of  the  scrotum  is  very  solid  and  thick. 

2.  Dartos. 

§ 2441.  Immediately  under  the  skin  we  find  the  dartos  ( tunica 
carnea , s.  dartos ),  which  is  situated,  in  regard  to  the  skin  of  the 
scrotum,  in  the  same  manner  as  the  adipose  substance  is  in  regard  to 
the  common  integuments,  excepting,  however,  in  men  who  are  very 
fleshy. 

It  is  very  vascular,  and  hence  it  is  reddish,  and  more  or  less  evi- 
dently fibrous.  As  it  is  also  very  contractile,  several  anatomists,  as 

(1)  J.  E.  Neubauer,  De  tunicis  vaginalibus  testis  et  funiculi  spermatid  dissertatio, 
Giessen,  1767. — A.  Monro,  Remarks  on  the  spermatic  vessels  and  the  scrotum , with 
its  contents  ; in  his  Medical  essays,  vol.  v.,  pt.  i.,  p.  205-222. — J.  Brugnone,  De 
testium  in  fœlu  positu,  eorum  in  scrotum  descensu,  tunicarum  quibus  continentur, 
numéro  et  origine,  Leyden,  1788. — P.  A.  Bondioli,  Sul  numéro  delle  tonache  vagi- 
nali  del  testicolo,  Padua,  1780. — J.  Tumiati,  Richerche  anatomische  intorno  alle 
tonache  dci  testicoli,  Venice,  1790. 


OF  THE  GENITAL  8YSTEM. 


415 


Winslow,(l)  have  considered  it  as  muscular,  and  have  compared  it  to 
the  subcutaneous  muscles  ; but  accidental  or  designed  emphysema, (2) 
and  the  comparative  results  obtained  by  macerating  it  and  the  platis- 
ma  myoides  muscle,  show  nothing  but  cellular  tissue. (3)  Probably, 
however,  it  makes  the  transition  from  the  mucous  to  the  muscular  tis- 
sue, and  there  is  between  it  and  the  other  muscles,  about  the  same  rela- 
tion as  between  it  and  the  muscles  of  the  superior  and  inferior  animals, 
in  whom  the  fibrous  structure  is  not  very  distinct,  and  is  concealed  in 
some  measure  by  the  gelatine,  an  element  of  muscous  tissuej  which 
envelops  and  conceals  the  fibrin  instead  of  leaving  it  exposed,  as  in 
the  superior  animals,  where  even  it  is  not  changed  into  this  substance. 

§ 2442.  The  dartos  forms  tw'o  distinct  sacs,  which  are  adapted  to 
each  other  on  the  median  line,  and  give  rise  to  the  septum  of  the  scro- 
tum {septum  scroti)  which  corresponds  to  the  raphe.  It  consequently 
separates  the  two  testicles,  not  only  in  respect  to  position,  but  also,  and 
to  a certain  extent,  in  that  of  vitality,  although  they  are  not  perfectly 
distinct.  Like  the  mucous  tissue  in  general,  it  is  more  or  less  infiltrated 
with  serum. 

3.  Cremaster  muscle. 

§ 2443.  The  cremaster  muscle,  the  fleshy  or  erythroid  tunic  ( tunica 
carnea,  s.  erythroides ),  is  situated  below  the  dartos  ; it  arises  from  the 
horizontal  ramus  of  the  pubis,  and  forms  a third  layer.  This  tunic  is 
formed  by  an  external  fasciculus,  which  descends  from  the  lower  edge 
of  the  two  internal  broad  abdominal  muscles,  and  by  an  internal  fasci- 
culus, which  is  generally  smaller,  but  is  sometimes  as  large,  and  rarely 
larger;  this  arises  from  the  horizontal  ramus  of  the  pubis.  It  surrounds 
the  spermatic  cord,  and  the  internal  tunics  of  the  testicle,  and  is  distri- 
buted principally  on  the  anterior  face,  even  when  it  embraces  all  the 
surface  of  the  organ.  Its  fibres  describe  arches  which  are  convex 
downward,  and  separate  more  from  each  other  the  lower  they  de- 
scend. 

When  there  are  muscular  fibres  on  the  whole  surface  of  the  organ, 
the  spermatic  cord  emerges  through  the  inferior  part  of  the  obliquus 
internus  muscle,  and  not  only  below  its  inner  edge.  Sometimes  the 
internal  fasciculus  is  really  or  apparently  deficient  ; the  latter  case  is 
most  common.  Sometimes  in  muscular  persons,  but  very  rarely,  fas- 
ciculi leave  the  cremaster  muscle,  and  go  with  the  spermatic  cord  into 
the  abdominal  cavity.(4) 

This  muscle  entirely  surrounds  the  cord  only  at  its  upper  part  ; be- 
low, its  fibres  separate. 

(1)  Traite  du  bas-ventre , § 499. 

(2)  Morgagni,  Adv.  anat.,  vol.  iv.  an.  1. 

(3)  Tumiati,  p.  142. 

(4)  Brugnone,  Observations  sur  les  vésicules  séminales  ; in  the  Mémoires  de  Turin, 
1786.  p.  610.— Penchienati,  ibid. 


41G 


DESCRIPTIVE  ANATOMY. 


It  is  itself  enveloped  by  a prolongation  of  the  thick  cellular  sheath 
■which  surrounds  the  obliquus  abdominis  externus  muscle,  and  its 
fibres,  although  separated  are  united  by  cellular  tissue.  This  cellular 
tissue  and  the  cellular  sheath  which  we  have  mentioned,  blend  to- 
gether below,  where  they  alone  envelop  the  testicle,  below  which  they 
unite  with  a common  vaginal  tunic,  to  give  rise  to  a short  but  solid 
tubercle. 

This  muscle,  which  is  more  developed  in  animals  than  in  man,  raises 
the  testicle. 

4.  Common  vaginal  tunic  of  the  testicles  and  spermatic  cord. 

§ 2444.  Next  to  the  erjhhroid  tunic  is  a layer  of  mucous  tissue, 
termed  the  common  vaginal  tunic  of  the  testicle  and  spermatic  cord 
( tunica  vaginalis  testis,  et.  funiculi  spermatid  communis ).  This  tunic 
arises  from  the  mucous  tissue  which  surrounds  the  peritoneum,  and 
covers  the  whole  cord  and  testicles  : we  may  by  inflating  its  lower  ex- 
tremity, pass  air  through  the  inguinal  ring  into  the  cellular  layer 
which  covers  the  anterior  and  posterior  faces  of  the  peritoneum,  and 
even  between  the  layers  of  the  mesentery. 

Prolongations  proceed  inward  from  the  external  edge  of  this  layer, 
and  go  toward  the  interior,  where  they  unite  together  the  vessels  of 
the  spermatic  cord  and  the  vas  deferens,  but  we  do  not  find  below  it 
the  pretended  proper  vaginal  tunic  of  the  spermatic  cord  ( tunica  vagi- 
nalis funiculi  spermatid  propria ),  which  Neubeauer  admits  and  which 
he  asserts  has  a distinct  cavity,  for  if  after  carefully  removing  this 
layer  from  its  external  surface,  the  vessels  of  the  spermatic  cord  be  in- 
flated, this  air  penetrates  into  every  part  ; and  farther,  air  injected  into 
it,  also  enters  the  vessels  of  the  cord.  Farther,  the  common  vaginal 
tunic  cannot  be  considered  at  its  upper  part  as  a special,  independent 
and  close  serous  cylinder,  if  we  reflect,  that  on  removing  the  cre- 
master muscle  which  covers  it,  it  ceases  to  be  impermeable  to  the  air, 
and  that  it  presents  this  character  only  so  long  as  it  is  surrounded  by 
the  muscle  and  its  tendon. 

We  can  at  most  admit  an  external  layer,  similar  to  the  loose  layer 
of  the  serous  membranes,  and  a reflected  fold  which  surrounds  and 
unites  the  vessels  of  the  spermatic  cord.  The  first  then  will  be  termed 
the  common,  and  the  second  the  special  tunic  of  the  cord. 

But  below,  as  far  as  it  covers  the  proper  vaginal  tunic  of  the  testicle, 
thi3  tunic  is  very  firm,  evidently  fibrous,  and  adheres  intimately  to  the 
proper  tunic  of  the  gland,  especially  near  its  lower  extremity. 

It  is  also  continuous  on  the  outside  in  this  part  with  the  two  tunics 
which  cover  it  externally.  * 


OF  THE  GEKITAL  SYSTEM. 


417 


6.  Proper  vaginal  tunic  of  the  testicle. 

§ 2445.  We  must  distinguish  from  this  layer  the  fifth  envelop  of 
the  testicle,  th e proper  vaginal  tunic  ( t . vaginalis  testis  propria),  from 
which  it  is  perfectly  separated. 

This  tunic  is  a compound  serous  membrane.  It  usually  has  an  oval 
form,  similar  to  that  of  the  testicle  ; it  however  is  rather  more  extern 
sive,  so  that  its  cavity  is  a third  higher  than  - the  gland,  being  two 
inches  and  a half  high.  Sometimes  a narrower  prolongation,  which 
varies  in  length,  leaves  the  anterior  part  of  its  surface,  and  penetrates 
below  into  the  common  vaginal  tunic,  and  the  two  cavities  uninter- 
ruptedly communicate. 

We  conclude  from  our  dissections,  that  this  prolongation  is  never 
■detached  exactly  from  its  summit,  but  always  a little  below  it. 

The  special  vaginal  tunic  receives  in  its  cavity  not  only  the  testicle, 
but  also  the  whole  epididymis  and  a portion  of  the  spermatic  cord.  At 
the  place  where  it  is  reflected  on  itself,  it  receives  directly  these  last 
two  parts  in  thé  commencement  of  its  internal  and  reflected  fold.  When 
it  has  enveloped  them,  it  passes  on  the  upper  and  lower  extremity  of 
the  testicle,  but  covers  the  gland  in  its  greatest  portion,  so  that  the 
summit  and  the  base  of  the  epididymis  are  only  covered  by  it  in  the 
point  by  which  they  look  toward  the  testicle.  Thence  it  goes  on  the 
whole  circumference  of  the  gland.  It  is  by  this  fold  that  the  spermatic 
vessels  pass  to  go  to  the  testicle,  and  enter  at  its  upper  and  posterior 
edge. 

The  two  layers  which  form  this  fold  are  slightly  united  by  cellular 
tissue,  so  that  they  are  easily  separated.  It  is  not  difficult  to  detach 
the  vaginal  tunic  from  the  epididymis  ; but  it  is  less  easy  to  separate 
it  from  the  testicle,  excepting  for  some  lines  near  the  posterior  edge. 

A portion  of  this  membrane  which  covers  the  testicle,  has  been  im- 
properly termed  by  Tumiati,(l)  the  conjunctiva.  It  is  usually  called 
the  external  layer  of  the  tunica  albuginea,  a term  still  more  incon- 
venient. 

6.  Fibrous  or  albugineous  tunic. 

§ 2446.  The  fibrous  or  albugineous  membrane  ( T.  albuginea , ano- 
nyma,  fibrosa)  is  the  last  and  the  most  internal  tunic  of  the  testicle. 
It  directly  envelops  the  substance  of  the  gland,  and  determines  its  form. 
It  is  thick,  solid,  silvery,  shining,  and  fibrous.  In  fact,  it  is  a fibrous 
membrane . 

It  forms  a single  cavity,  and  is  perforated  at  its  upper  extremity  for 
the  passage  of  the  seminal  ducts,  and  at  the  posterior  edge  for  thjat  of 
the  spermatic  vessels. 


(I)  Loc.  cit.,  p.  146. 


418 


DESCRIPTIVE  ANATOMY. 


b.  Substance  of  the  testicle. 

§ 2447.  On  the  inner  side  of  the  albugineous  membrane,  to  which 
it  adheres  in  great  part  but  slightly,  is  the  substance  of  the  testicle,(l) 
a soft  brownish  yellow  mass,  divided  by  the  blood-vessels  of  the  tunic 
into  several  lobules  ( lobidi),{2 ) situated  one  above  another.  This  sub- 
stance is  composed  principally  of  very  many  minute  canals,  which 
are  single,  and  do  not  ramify  and  interlace  with  each  other  ; they  are 
termed  the  seminal  canals  ( canaliculi  semmales,  s,  vascvla  serpentina , 
s.  ductus  seminiferi).  Each  lobule  includes  one  of  these  canals.  Their 
circumvolutions,  and  they  themselves,  are  united  very  loosely  by  a fine 
cellular  tissue,  so  that  they  may  be  easily  detached.  But  it  is  much 
more  easy  to  prove  by  maceration,  their  very  great  number,  which  is 
about  three  hundred.  Each  of  them  is  about  sixteen  feet  long  and 
broad.  If  attached  to  one  another,  they  would  consequently  ex- 
tend about  five  thousand  feet. 

§ 2448.  These  canals  unite  near  the  upper  extremity  of  the  testicle, 
into  several  larger  canals,  which  pass  through  the  albugineous  tunic, 
and  soon  produce  about  twenty  others,  which  are  still  larger,  called  the 
vasa  efferentia.  These  latter  are  united  in  a single  fasciculus  by  a 
mucous  tissue,  wind  around  from  below  upward,  and  form  the  rounded 
and  enlarged  head  of  the  epididymis. 

B.  EPIDIDYMIS. 

§ 2449.  The  epididymis{ 3)  is  the  commencement  of  the  excretory 
duct  of  the  testicle.  It  begins  at  the  upper  extremity  of  this  gland 
by  a thicker,  enlarged,  and  rounded  part,  called  the  head , and  de- 
scends along  its  posterior  and  upper- edge.  The  fasciculi  which  form 
the  seminal  passages,  are  still  separated  in  the  head  of  the  epididymis, 
although,  according  to  our  observations,  this  part  seems  to  be  perfora- 
ted, even  at  its  upper  extremity,  only  by  a simple  and  very  tortuous 
canal,  into  which  the  seminal  passages  severally  open. 

The  thinnest  and  longest  part  of  the  epididymis,  that  termed  its 
tail  ( cauda ),  is  a simple,  but  very  tortuous  canal  ; it  is  at  first  very 
narrow,  but  gradually  enlarges  very  much,  and  becomes  more  tortu- 
ous. It  is  but  loosely  attached  to  the  proper  vaginal  tunic  of  the  tes- 
ticle by  a fold  of  this  membrane,  and  is  reflected  on  itself  from  below 
upward  at  its  lower  extremity,  and  is  then  called  the  ductus  deferens. 

It  is  about  thirty  feet  long. 

(1)  A.  Haller,  De  vasis  seminalibus  observationes,  Gottingen,  1745. — A.  Monro, 
Description  of  the  seminal  vessels  ; in  the  Edinb.  essays  phys.  and  literary,  yo\.  i. 
xvi. — Id.,  De  testibus  et  de  semine  in  variis  animalibus , Edinburg,  1755. — Id.,  Of 
the  seminal  ducts  ; in  the  Observations  anatomic,  and  physiol,  wherein  Hunter’s 
claim  some  discoveries  is  examined , Edinburg,  1753. — G.  Prochaska,  Beobach- 
tungen über  die  Samengange  ; in  the  Abhandl.  der  Jos.  Akad.,  vol.  i.  p.  198-213. 

(2)  B.  S.  Albinus,  De  teste  humano  ; in  the  Ann.  acad.,  1.  ii.  c.  xii. 

(3)  B.  S.  Albinus,  Dc  epididymo  ; in  the  Ann.  acad.,  1.  ii.  c.  vi. 


OF  THE  GENITAL  SYSTEM- 


419 


C.  DUCTUS  DEFEHENS. 

§ 2450.  The  ductus  deferens  or  vas  deferens, ( 1)  ascends  along  the 
posterior  and  upper  edge  of  the  testicle,  first  in  a straight  line,  then  ob- 
liquely from  within  outward.  It  is  tortuous  at  its  origin,  but  soon  be- 
comes straight,  and  joins  the  spermatic  vessels,  with  which  it  is  united 
by  cellular  tissue,  to  give  rise  to  the  spermatic  cord.  It  ascends  di- 
rectly to  the  inguinal  ring  ; but  in  this  place  its  direction  changes,  and 
it  goes  from  below  upward,  and  from  within  outward  in  the  inguinal 
canal,  within  which  we  observe  the  relation  we  have  indicated,  be- 
tween the  blood-vessels  and  the  lymphatics,  and  the  ductus  de- 
ferens. On  leaving  this  canal  it  crosses  the  epigastric  artery,  and  as- 
cends directly  before  it,  then  turns  behind  it  on  the  inside,  and  upward, 
and  thus  comes  into  the  abdominal  cavity.  Thence  it  leaves  the  sper- 
matic vessels  at  a more  or  less  acute  angle,  goes  inward  and  down- 
ward always  on  the  outside  of  the  peritoneum,  which  covers  only  its 
posterior  part,  and  descends  into  the  small  pelvis,  converging  very 
much  toward  that  of  the  opposite  side. 

§ 2451.  The  ductus  deferens  is  situated  in  the  pelvis,  on  the  pos- 
terior face  of  the  bladder. 

It  dilates  and  gradually  thickens  in  its  course.  At  its  lowest  part, 
which  suddenly  dilates  considerably,  it  becomes  at  the  same  time  very 
tortuous,  less  so,  however,  than  at  its  origin,  and  gives  rise  on  the  out- 
side upward  and  backward,  to  a great  enlargement,  to  a kind  of  purse 
or  cul-de-sac,  termed  the  seminal  vesicle. 

Two  very  different  substances  enter  into  its  composition.  The  ex- 
ternal, which  is  about  half  a line  thick,  is  of  a brownish  yellow  color, 
very  hard  and  solid.  Very  probably  it  is  irritable,  although  fibres  are 
distinctly  seen  in  it  very  rarely.  Sometimes,  however,  we  have  ob- 
served circular  fibres  which  it  was  impossible  to  mistake.(2) 

The  inner  substance  is  whitish,  and  easily  separable  from  the  pre- 
ceding, with  which  it  is  united  only  by  a loose  cellular  tissue.  It  is  a 
mucous  membrane,  a prolongation  of  that  of  the  urethra.  It  is  smooth 
in  most  of  its  extent,  but  reticulated  below  for  an  inch  or  turn. 

D.  SEMINAL  VESICLES. 

§ 2452.  The  seminal  vesicles  ( vésicules  séminales,  s.  parastatœ)( 3) 
are  situated  one  on  each  side,  on  the  outside  of  the  corresponding 
ductus  deferens.  They  are  also  intimately  adapted  to  the  poste- 
rior face  of  the  bladder,  and  are  covered  posteriorly  by  the  perito- 

(1)  B.  S.  Albinus,  De  vasis  defer entib us,  vesiculis  seminalibus,  emissariis  quibus 
ad  urethram  pertinent,  ostiolis  in  capite  gallmaginis  ; in  the  Ann.  acad.,  1.  iv.  c.  iii. 
p.  16. 

(2)  Leuwenhock  (ep.  xli)  has  seen  also  longitudinal  fibres. 

(3)  Haller,  Observationes  dc  vasis  seminalibus , Gottingen,  1745. 


420 


DESCRIPTIVE  ANATOMY. 


neum  which  adheres  to  them  but  slightly.  Their  breadth  is,  however, 
slight  in  proportion  to  their  length,  for  they  are  about  two  or  three 
lines  broad,  and  four  or  five  inches  long;  but  they  appear  much  shorter, 
as  they  are  very  tortuous. 

They  are,  however,  not  always  simply  tortuous  or  similar  to  a long 
cul-de-sac,  as  Lealis,  and  since  his  time  Caldani,(l)  have  asserted.  In 
fact,  they  more  commonly  ramify. 

Their  inner  membrane  presents  numerous  inequalities,  which  pro- 
duce a kind  of  net-work  with  irregular  meshes.  There  is  also  between 
the  largest  folds,  a considerable  number  of  less  prominent  folds,  which 
also  render  their  inner  face  still  more  uneven.  This  arrangement  es- 
tablishes a striking  analogy  between  the  seminal  vesicles  and  the  gall- 
bladder. 

§ 2453.  The  lower,  extremity  of  the  seminal  vesicle  and  of  the  duc- 
tus deferens,  opens  into  an  extremely  narrow  duct  some  lines  long, 
termed  the  ejaculatory  duct  ( ductus  ejaculatorius).  This  duct  ap- 
proaches from  behind  forward,  and  from  below  upward,  that  of  the 
other  side,  enters  into  the  substance  of  the  prostate  gland,  and  opens 
into  the  urethra,  directly  at  the  side  of  this  latter,  in  the  centre  of  the 
verumonianum. 

E.  PBOSTATE  GLAND. 

§ 2454.  The  prostate  gland  ( prostata ) is  a triangular  (2)  body, 
usually  of  the  size  and  form  of  a chestnut  ; is  about  an  inch  broad,  one 
high,  and  half  an  inch  thick,  and  weighs  about  five  drachms. 

It  is  situated  below  and  before  the  bladder,  and  surrounds  the  com- 
mencement of  the  urethra  posteriorly  and  on  the  sides. 

It  is  whitish,  hard,  and  solid,  and  it  is  surrounded  by  a fibrous  and 
resisting  membrane. 

It  is  composed  of  three  tubes,  two  lateral  and  a central,  which  is 
posterior  and  smaller. 

The  middle  lobe  is  situated  behind  and  between  the  two  lateral  lobes 
and  the  ejaculatory  ducts,  and  likewise  between  these  latter  and  the 
bladder  ; it  is  rounded  and  smaller  than  the  lateral  ; its  volume  how- 
ever varies.  In  the  centre  of  its  lower  face  is  an  oblong  rounded  emi- 
nence, which  terminates  anteriorly  in  a narrow  and  elongated  point. 
This  eminence  has  been  termed  from  its  form,  the  verumontanum 
( caput  gallinaginis , s.  verumontanum,  s.  colliculus  seminalis).  It  pre- 
sents at  its  centre  one  or  two  orifices  of  the  ejaculatory  ducts,  and  on 
the  sides  a considerable  number  of  orifices  leading  to  the  excretory 
canals,  -which  are  distributed  in  the  substance  of  the  glanfl.  These 
orifices  give  passage  to  a yellowish  fluid,  the  fluid  of  the  prostate , 
which  mingles  with  the  semen  at  the  time  of  emission. 

(1)  F.  Caldani,  Opusc.  anut.,  Padoue,  1803, 

(2)  Home,  On  the  prostrate  gland. 


OF  THE  GENITAL  SYSTEM. 


421 


The  excretory  ducts  of  the  middle  lobe  pass  immediately  through 
the  membranes  of  the  bladder,  behind  and  on  the  outside  of  the  veru- 
montanum. 

II.  ORGANS  OF  COPULATION  OR  PENIS. 

A.  FORM  AND  SITUATION. 

§ 2455.  The  penis  (penis,  s.  coles,  s.  priapus,  s.  membrum  virile ) 
is  situated  forward,  and  entirely  on  the  outside  of  the  pelvis,  below  the 
symphysis  pubis,  between  the  thighs.  Its  form  is  nearly  cylindrical. 
The  common  excretory  duct  of  the  urine  and  semen,  the  urethra , 
passes  through  it. 

It  is  entirely  surrounded  by  a prolongation  of  the  skin,  which  in  this 
place  is  thin  and  destititute  of  hairs,  and  fat.  External  examination 
shows  even  through  the  skin,  that  it  suddenly  enlarges  at  its  anterior 
extremity,  where  it  presents  a considerable  prominence,  and  that  it  ter- 
minates in  a blunt  point.(l) 

a.  Gians. 

§ 2456.  This  enlarged  portion  is  the  glans  penis, (2)  a rounded  tri- 
angular body,  terminated  posteriorly  by  a rounded  sac,  termed  the 
crown  ( corona  glandis ),  which  entirely  surrounds  it,  and  forward  by  a 
longitudinal  groove,  the  external  orifice  of  the  urethra.  The  contracted 
portion,  situated  behind  the  glans,  is  its  neck. 

The  glans  is  not  exposed  ; it  is  covered  by  three  layers  of  skin. 

b.  Prepuce. 

§ 2457.  The  first  two  layers  are  united  by  cellular  tissue,  so  that 
the  external  is  turned  outward,  and  the  internal  inward.  They  form 
th e prepuce  (preputium).  This  fold  is  fitted  to  the  glans,  but  is  not 
attached  to  it,  so  that  it  can  be  drawn  backward  and  forward  ; the  first 
motion  exposes  the  glans,  the  second  covers  it. 

The  internal  layer  of  the  prepuce  is  soft,  reddish,  moist,  and  similar 
to  a mucous  membrane. 

In  the  centre,  where  the  two  layers  are  continuous  with  each  other, 
the  prepuce  presents  apparently  a rounded  opening,  which  corresponds 


(1)  F.  Ruysch,  Responsio,  &c.  in  the  epist.  xv.  De  vas.  sanguineorum  extremit., 
&c.  Iiisce  accedunt  nonnulla  circa  penem  detecta. — B.  S.  Albinus,  Dc  Ruyschiano 
involucro  penis  externo,  et  de  tunica  cellulosa  penis  ; in  the  Ann.  acad.,  1.  ii.  c.  xi. — 
F.  Ruysch,  De  involucro  penis  externo,  ibid.  ].  ii.  c.  xiii. — L’Admiral,  Iconpenis  hu- 
mani  cera  præparati,  Amsterdam,  1741. — J.  H.  Thaut.  Diss.  de  virgae  virilis  statu 
sano  el  morboso,  Wurzburg’,  1808. 

(2)  F.  Ruysch,  Glandis  in  pene  vera  structura  noviter  detecta  ; in  the  Obs.  med. 
chir.,  cap.  c. — B.  S.  Albinus,  De  integumentis  glandis  penis  ; in  the  Annot.  acad., 
lib.  iii.  c.  ix. 

VOL.  Ill, 


54 


422 


DESCRIPTIVE  ANATOMY. 


to  the  anterior  oiifice  of  the  glans,  and  which  disappears  when  the  pre- 
puce is  drawn  entirely  backward.  The  latter  is  corrugated  trans- 
versely in  the  same  proportion. 

The  internal  layer  of  the  prepuce  is  reflected  a second  time  behind 
the  glans,  but  here  from  behind  forward,  and  covers  this  organ,  inti- 
mately adhering  to  its  tissue.  This  adhesion  is  almost  gradual  on  the 
circumference  of  the  glans.  In  fact  the  internal  fold  of  the  prepuce  is 
loose  at  its  upper  part,  where  it  is  attached  but  feebly  to  the  penis  ; 
but  near  the  centre  of  its  lower  part,  it  is  tense,  short,  and  intimately 
united  to  the  corresponding  portion  of  the  glans,  and  forms  a short  per- 
pendicular fold. 

This  portion  of  the  prepuce  is  termed  the  frenum  of  the  glans  ( fre- 
nulum glandis): 

All  around  the  neck  and  posterior  face  of  the  crown,  the  most  inter- 
nal cutaneous  fold  of  the  glans  presents  numerous  rounded  depres- 
sions, termed  the  glands  of  Tyson  ( glandulœ  Tysonianœ),  which  se- 
crete a thick  and  whitish  fluid. 

This  fluid  ( smegma  prœputii)  has  a disagreeable  smell,  and  tends 
very  much  to  solidify. 

3.  SIZE  or  THE  PENIS. 

§ 2458.  When  not  erected,  the  penis  is  about  three  or  four  inches 
long  and  one  inch  thick. 

C.  COMPOSITION. 

§ 2459.  The  penis  is  attached  to  the  skin,  which  covers  it  only  very 
loosely. 

It  is  composed  of  a thick  and  fibrous  membrane,  which  determines 
its  form,  and  of  a spongy  tissue,  principally  formed  by  dilated  veins, 
which  is  then  divided  into  three  distinct  bodies.  The  two  upper  and 
lateral  are  termed  the  cavernous  bodies  of  the  penis  ( corpora  spongiosa, 
s.  cavernosa , s.  nervosa  penis),  the  inferior  is  termed  the  spungy  body  of 
the  urethra  ( corpus  spongiosum , s.  cavernosum  urethrae). 

The  cavernous  bodies  of  the  penis  and  urethra  are  generally  de- 
scribed as  a collection  of  different  cellules  of  the  vessels  ; but  these 
cellules  are  in  fact  only  dilated  veins,  and  the  spungy  bodies  are  com- 
posed of  a very  complex  net-work  of  arteries  and  veins,  as  Vesalius(l) 
and  Maipighi(2)  had  already  stated  generally  in  regard  to  the  penis, 
and  Hunter, (3)  of  the  spungy  body  of  the  urethra  particularly. 

(1)  De  corporis  humani  fabricà,  lib.  v.  c.  xiv.  Corpora  have...  enata  ad  eumfere 
modum,  ac  si  cx  innumcris  arteriarum.  venarumquefasculis  quam  tenuissimis,  si - 
uiulquc  proximé  implicatis,  retia  quœdam  efformarentur,  orbiculatim  a nervea  ilia 
■membrane aque  substantia  comprehcnsa. 

(2)  Diss.  epist.  varii  argumenti  ; in  the  Opp.  omn.,  vol.  ii.  p.  221.  Sinuum  spe- 
eiem  in  mammarum  tubulis  et  in  pane  habemus  ; in  his  nonnihil  sanguinis  reperi- 
tur,  ita  ut  videantur  venarum  diverticula , vel  saltern  ipsarum  appendices. 

(3)  Hunter,  Obs.  on  certain  parts  of  the  animal  economy,  p.  43. 


ÜF  THE  GENITAL  SYSTEM. 


423 


This  structure  had  been  perfectly  demonstrated  in  the  penis  of  the 
large  animals,  as  the  elephant  and  the  horse,  partly  by  Duvernoy,(l) 
but  particularly  by  Cuvier(2)  and  Tiedemann  ;(3)  in  the  penis  of  man 
by  Ribes.(4)  Moreschi,  and  Panizza. 


a.  Cavernous  bodies  of  the  penis. 


§ 2460.  The  cavernous  bodies  of  the  penis  form  most  of  the  member, 
that  is,  its  upper  parts  and  its  sides.  They  are  more  broad  than  high. 

They  alone  have  evidently  a fibrous  envelop,  the  fibres  of  which  in- 
terlace with  each  other,  and  are  longitudinal. 

They  arise  on  each  side  by  a branch  about  half  an  inch  long,  which 
comes  from  the  ascending  ramus  of  the  ischium  ; the  two  branches 
ascend  to  meet  each  other,  and  unite  before  the  symphysis  pubis, 
where  they  are  surrounded  in  their  whole  circumference  by  a common 
envelop. 

Although  they  appear  simple  externally,  these  bodies  are  however 
imperfectly  divided  into  two  halves,  a right  and  a left,  by  a perpendicu- 
lar septum  ( septum  corporum  cavernosorum ),  which  extends  almost 
fheir  whole  length,  and  is  a prolongation  of  the  external  fibrous  mem- 
brane. This  septum  is  formed  of  very  long  fibres,  compressed  from 
right  to  left,  which  extend  the  whole  heigth  of  the  cavernous  bodies, 
and  which,  forming  posteriorly  an  almost  perfect  septum,  proceed 
forward,  growing  thinner,  and  diminishing  much  in  number  so  as 
to  leave  between  them  greater  or  less  spaces.  The  separation  which 
takes  place  between  the  two  cavernous  bodies  at  their  posterior  extre- 
mity, then  gradually  disappears  forward  entirely.  They  however  se- 
parate still  more  at  their  anterior  extremity,  although  apparently  only 
on  the  outside,  since  the  external  part  of  their  circumference  is  much 
longer  than  the  internal,  whence  their  anterior  faces,  surrounded  by 
the  external  tunic,  unite  from  without  inward  at  a re-entering  angle. 


b.  Urethra. 

§ 2461 . The  urethra( 5)  proceeds  along  the  lower  face  of  the  penis. 
It  begins  in  the  prostate  gland,  where  it  is  broad.  In  front  of  this  point 


(1)  Conm.  Petrop.  a.  ii.  p.  400.  Venarum  ductus  solummodo  cribriformes, fara- 
minibus  undique  pertusi  ac  reluti  erosi,  a cellulis  œgre  discriminandi  extra  capsu- 
lam  penis , venarum  (s.  brevium  tubulorum  verticalium)  formam  induenlia,  in  con 
spectum  veniunt. 

(2)  Anat.  comparée,  vol.  iv. 

(3)  F.  Tiedemann,  Notice  sur  less  corps  caverneux  de  la  verge  du  cheval , suivie 
de  quelques  réfléxions  sur  le  phénomène  de  l'érection  ; in  the  Journ.  compl.  des.  sc. 
méd.,  vol.  iv.  p.  282. 

(4)  Exposé  sommaire  de  quelques  recherches  anatomiques , physiologiques  et  patho- 
logiques ; in  the  Mém.  de  la  soc.  méd d’emul.,  vol.  vii.  p.  605. 

(5)  A.  Littré,  Description  de  l' urètre  de  l'homme;  in  the  Mém.  de  Pc, ris,  1700, — 
J.  P,  Werne,  Structura  urethra- , Leyden,  1752. 


424 


DESCRIPTIVE  ANATOMY. 


it  contracts  much  for  about  an  inch,  so  as  to  be  only  one  or  two  lines 
in  diameter.  This  contracted  portion  is  called  the  isthmus  of  the  ure- 
thra (isthmus  urethrcc).  It  ascends  a little  obliquely  from  below  up- 
ward, and  from  behind  forward,  below  the  symphysis  pubis,  from  which 
it  is  about  an  inch  distant,  surrounded  by  a loose  spungy  tissue,  like 
the  urethra  in  the  female,  which  corresponds  only  to  this  portion  of  the 
urethra  in  the  male.  The  canal  afterward  enlarges  very  much,  and 
is  then  surrounded  in  the  rest  of  its  extent  by  the  cavernous  body  of 
the  urethra,  the  size  of  which  is  generally  in  direct  ratio  to  its  diameter. 

The  cavernous  body  of  the  urethra  is  largest  at  the  second  promi- 
nence, where  it  forms  a considerable  enlargement  called  the  bulb  oj 
the  urethra  (bulbus  urethrcc) . 

On  leaving  this  point  the  urethra  contracts  very  much.  Its  diame- 
ter continues  about  the  same  to  the  anterior  extremity  of  the  penis  ; 
but  directly  behind  and  within  the  glans  it  enlarges  a third  time  to 
form  the  navicular  fossa  ( fossa  navicularis) . 

The  cavernous  body  of  the  urethra  is  enveloped  only  by  a dense 
cellular  tissue,  which  is  not  fibrous.  It  is  finer,  and  of  a more  delicate 
tissue  than  that  of  the  penis,  and  has  no  septum.  It  alone  forms  the 
glans  anteriorly. 

Below  this  body  is  a thin  and  reddish  mucous  membrane,  which  is 
united  intimately  with  it,  and  has  longitudinal  folds. 

This  membrane  presents  numerous  cavities  arranged  successively 
as  culs-de-sac  in  a single  series,  termed  the  glands  of  Littré. 

These  cavities  are  sometimes  three  lines  deep.  They  are  seen  only 
at  the  lower  part  of  the  circumference  of  the  urethra,  and  their  direc- 
tion is  such  that  their  orifice  looks  forward  and  their  cul-de-sac  back- 
ward^ 1) 

(1)  As  Ducamp’s  researches  have  reduced  the  treatment  of  strictures  of  the 
urethra  almost  to  mathematical  accuracy,  it  is  necessary  to  have  a more  extensive 
knowledge  of  this  canal  than  has  been  given  by  Meckel.  This  may  be  found  in  a 
memoir  of  Amussat  ( Remarques  sur  l'urètre  de  l’homme  et  de  la  femme  ; in  the 
Archiv,  gén.  de  mêd .,  vol.  iv.,  p.  31  and  347),  who  has  ascertained  a very  important 
practical  fact,  that  even  in  young  subjects  the  urethra  is  straight  or  nearly  straight 
when  the  rectum  is  empty,  and  the  penis  is  directed  from  before  backward.  We 
distinguish  in  it  three  portions  : the  prostatic  portion,  with  thin  parietes,  which  is 
enveloped  by  the  prostate  gland  ; it  is  about  twelve  or  fifteen  lines  long;  the  mem- 
branous portion,  the  parietes  of  which  are  a little  thicker  ; it  is  from  nine  to 
twelve  inches  long  ; and  the  spungy  portion,  which  is  from  about  six  to  seven  inches 
long.  Most  authors  consider  the  whole  canal  as  ten  or  twelve  inches  long  ; but  it 
is  only  nine,  and  very  frequently,  at  least  sometimes,  even  less  than  eight,  as  has 
been  stated  by  P.  Whately  (An  improved  method  of  treating  strictures  in  the  urethra , 
London,  1816,  p.  68).  We  may  then  estimate  its  mean  length  as  between  eight  and 
nine  inches,  nine  inches  and  six  lines  and  seven  inches  and  six  lines  being  the  two 
extreme  proportions  observed  by  Whately  in  forty-eight  different  subjects.  It  is  not 
equally  broad  in  every  part.  It  follows,  from  Sir  E.  Home’s  researches  (Practical 
observations  on  the  treatment  of  strictures  in  the  urethra , London,  1805,  vol.  i.,  p.  24), 
that  its  diameter  is  four  lines  in  most  of  its  extent,  and  that  its  external  orifice  is  at 
least  one  line  narrower,  since  it  is  only  from  two  and  a half  to  three  lines  in  diame- 
ter. Amussat  has  since  proved  that  the  urethra,  when  the  parts  which  cover  it  are 
removed  and  it  is  reduced  almost  to  the  mucous  membrane,  represents  a cone,  the 
base  of  which  is  turned  backward,  and  which  is  slightly  prominent  at  its  membra- 
nous portion,  contracts  opposite  the  bulb  to  enlarge  suddenly  at  the  commencement 


OF  THE  GENITAL  SYSTEM. 


425 


c.  Cowper’s  glands. 

§ 2462.  Besides  the  testicles  and  the  prostate  gland,  we  also  fre- 
quently, but  not  always,  find  two  or  three  other  small,  yellowish, 
oblong,  rounded,  hard  glands  formed  of  several  lobes  enveloped  by  a 
very  dense  aponeurotic  sheath.  These  glands  are  about  the  size  of 
a large  pea,  are  situated  directly  below  the  upper  part  and  a little 
before  the  prostate  gland. 

Their  ducts  are  about  an  inch  and  a half  long,  go  forward  in  the 
bulb  of  the  urethra,  and  open  from  below  upward  in  the  sides  of  this 
canal  by  distinct  orifices. 

The  two  posterior  lateral  are  termed  the  glands  of  Cowper. {V)  The 
anterior,  which  is  unmated,  is  smaller  and  much  less  constant  than 
the  other  two  ; it  is  termed  the  anterior  prostate  gland  ( antiprostata .) 

D.  MUSCLES  OF  THE  PERINEUM. 

a.  Special  muscles  of  the  penis. 


§ 2463.  The  penis  has  three  muscles,  one  of  which,  the  ischio-ca- 
vernosus , belongs  to  the  cavernous  bodies  of  the  penis,  the  second,  the 
bulbo-cavernosus , belongs  to  the  spungy  body  of  the  urethra,  while  the 
third,  the  constrictor  urethrae  muscle,  moves  the  membranous  portion 
of  this  canal.  All  three  are  situated  at  the  extremity  of  the  penis. 

a.  Ischio-cavernosus. 

§ 2464.  The  ischio-cavernosus  muscle,  ischio-uretral , Ch.  (JW.  ischio- 
cavernosus ■,  s.  erector  penis),  resembles  that  of  the  clitoris  in  its  origin, 
attachments,  direction,  and  mode  of  action  ; but  it  is  much  larger,  and 
sometimes  arises  by  a second  head  from  the  sciatic  tuberosity. 


of  the  spungy  portion,  and  diminishes  imperceptibly  to  the  meatus,  so  that  there  is 
no  enlargement  in  the  place  corresponding  to  the  glans,  that  is,  in  the  navicular 
fossa.  Amussat  explains  the  appearance  of  an  enlargement  in  thi3  latter  point,  by 
saying  that  the  tissue  of  the  glans  is  less  soft  and  the  mucous  membrane  is  attached 
to  it  more  intimately,  so  that  in  dividing  the  urethra,  the  two  halves  of  the  glans 
remain  firm  and  distinct,  while  the  proper  spungy  tissue  contracts  and  collapses, 
being  freed  from  the  blood  within  it.  That  the  navicular  fossa  is  only  apparent  is 
proved  by  extending  transversely  the  spungy  portion  behind  the  glans,  when  it  be- 
comes as  broad  as  that  situated  in  the  body.  He  has  also  given  a very  exact  plate 
of  the  urethra  ( loc . cit.,  pi.  iii.,  fig.  1 and  2).  P.  T. 

(1)  G.  Cowper,  Glandularum  quarumdam  nv.per  detectarum  descriptio,  London, 
1702. — L.  Terranus,  De  glandulis  universim  et  spedatim  ad  urethram  virilem 
novis,  Leyden,  1729. — G.  A.  Haase,  De  glandulis  Coicperi  mucosis,  Leipsic,  1803. 


426 


DESCRIPTIVE  ANATOMY. 


b.  Bulbo-cavernosus. 

§ 2465.  The  bulbo-cavernosus  muscle,  bulbo-uretral,  Ch.  (JM.  acce- 
lerator urinœ,  s bulbo-cavernosus ),  is  thin,  flat,  and  nearly  rhomboidal. 
It  surrounds  the  bulb  and  the  posterior  part  of  the  urethra.  It  arises 
forward  from  the  posterior  part  of  the  cavernous  body  of  the  penis,  and 
backward  from  the  upper  part  of  the  lateral  wall  of  the  bulb  of  .the 
urethra.  It  terminates  anteriorly  by  a straight  edge,  which  descends 
from  without  inward  and  from  before  backward,  and  posteriorly  by  a 
rounded  edge.  It  is  formed  at  its  anterior  part  by  very  oblique  fibres, 
and  at  its  posterior  part  by  fibres  which  are  nearly  transverse.  It 
blends  on  the  median  line  with  that  of  the  opposite  side  so  intimately, 
that  frequently  they  are  not  separated  by  a median  tendinous  line. 


c.  Constrictor  urethræ. 

§ 2466.  The  constrictor  urethræ.  muscle,  pubo-uretral , Ch.  (JM. 
constrictor  urethrae,  s.  pub  o-urethr  alls), ( 1)  is  elongated,  quadrilateral, 
and  flattened  from  without  inward.  It  arises  by  a short  tendon  a little 
above  the  lower  edge  of  the  symphysis  pubis,  some  lines  below  the 
tendinous  attachment  of  the  bladder,  directly  at  the  side  of  the  tendon 
of  that  of  the  synonymous  muscle,  on  the  inner  face  of  the  symphysis. 
Thence  it  descends  enlarging,  is  first  next  that  of  the  opposite  side, 
but  removes  from  it  on  arriving  at  the  membranous  portion  of  the 
urethra,  to  which  it  is  attached,  and  below  which  it  is  blended  with 
its  synonymous  muscle,  so  that  generally  only  a tendinous  line,  corre- 
sponding to  the  median  line,  indicates  their  separation. 

It  usually  blends  at  its  anterior  extremity  with  the  posterior  extre- 
mity of  the  bulbo-cavernosus  muscle. 

It  is  frequently  united  at  its  lower  part  by  some  fibres  to  the  levator 
ani  muscle  ; but  in  the  rest  of  its  extent  it  is  separated  from  it  only 
by  veins,  which  arise  from  the  prostate  gland  and  the  bladder,  pro- 
ceed from  behind  forward,  and  empty  into  the  great  dorsal  vein  of  the 
penis. 

The  two  muscles  form  a ring  around  the  membranous  portion  of 
the  urethra  ; they  compress  it,  and  by  their  convulsive  contractions 
very  much  increase  the  difficulty  of  passing  a sound  through  this  por- 
tion of  the  canal. 

(1)  Wilson,  Description  of  two  muscles  surrounding  the  membranous  part  of  the 
urethra;  in  the  Med.  chir.  trails,  of  London , vol.  i.,  p.  175. 


or  THE  GENITAL  SYSTEM. 


427 


b.  Common  muscles  .of  the  genital  parts,  the  rectum,  and  the  urinary  passages, 
a.  Transversi  perinei. 

§ 2467.  We  usually  find  two  muscles  on  each  side,  the  transversi 
perinei  muscles,  iscliiu  perineal,  Ch.,  which  go  inward  from  the  ischium 
and  the  pubis,  and  which  are  similar,  as  they  are  .both  long. 

§ 2468.  The  posterior  and  inferior  arises  from  the  inner  face  of  the 
sciatic  tuberosity,  goes  from  without  inward  and  from  behind  forward, 
and  blends  particularly  in  the  female  with  that  of  the  opposite  side 
and  with  the  anterior  extremity  of  the  sphincter  ani  externus  muscle, 
and  slightly  also  with  the  posterior  extremity  of  the  bulbo-cavernosus 
and  the  constrictor  vaginae  muscles. 

In  acting  with  its  synonymous  muscle  it  draws  the  anus  a little 
backward  and  compresses  it  from  before  backward,  and  thus  favors 
the  expulsion  of  the  feces. 

§ 2469.  The  anterior  and  superior  arises  from  tlie  inner  face  of  the 
lower  part  of  the  descending  ramus  of  the  pubis,  where  it  is  frequently 
united  intimately  to  the  preceding,  goes  inward  and  a little  forward, 
blends  again  with  the  preceding,  that  of  the  opposite  side,  and  the 
sphincter  ani  externus  muscle,  and  likewise  with  the  bulbo-cavernosus 
and  the  constrictor  vaginæ  muscles,  farther  forward  than  that  we  have 
mentioned. 

It  acts  like  the  posterior,  but  it  also  contributes  to  open  in  the  male 
the  posterior  part  of  the  urethra,  and  in  the  female  the  vagina. 

§ 2470.  The  posterior  transversus  perinei  muscle  is  frequently  de- 
ficient. In  man  the  two  muscles  are  much  nearer  each  other  and 
much  slighter  than  in  the  female.  In  the  latter  we  sometimes  find  a 
third,  situated  between  the  other  two. 

b.  Levator  ani. 

§ 2471.  The  levator  ani  muscle,  sous-pubio-coccygien , Ch.,  is  broad, 
thin,  and  semicircular.  It  arises  forward  and  upward  from  the  lower 
part  of  the  symphysis  pubis  and  the  horizontal  ramus  of  the  pubis  ; it 
also  comes  from  the  inner  face  of  the  body  of  the  ischium  to  the  sciatic 
spine,  above  and  on  the  inside  of  the  upper  edge  of  the  obturator  in- 
ternus muscle.  Thence  it  goes  inward,  downward,  and  backward,  so 
that  its  anterior  fibres  are  almost  perpendicular  and  the  posterior  trans- 
verse. 

It  passes  behind  the  lower  part  of  the  rectum,  and  is  attached  by 
short  tendinous  fibres  to  the  lateral  edge  of  the  three  lower  pieces  of 
the  coccyx  by  the  posterior  part  of  its  inner  edge,  while  by  the  ante- 
rior it  blends  with  that  of  the  opposite  side. 


428 


rF.SCIUFTIVE  ANATOMY. 


It  follows  from  this  arrangement  that  the  two  muscles  form  a large 
ring,  which  surrounds  the  lower  extremity  of  the  rectum  posteriorly, 
and  which  in  the  female  is  attached  very  intimately  to  the  vagina  be- 
fore arriving  at  the  rectum. 

In  the  female  the  anterior  part  which  arises  from  the  symphysis 
pubis  is  often  separated  from  the  rest. 

This  muscle  raises  the  lower  part  of  the  rectum,  contracts  it,  and 
thus  prevents  the  prolapsus  of  the  intestine,  also  favors  the  expulsion 
of  the  feces,  carries' forward  and  upward  the  coccyx,  which  has  been 
pushed  forward  by  the  feces  and  excrements,  and  by  the  fetus  in  par- 
turition, favors  the  expulsion  of  the  urine  and  semen  by  compressing 
the  bladder  and  seminal  vesicles,  and  finally  prevents  prolapsus  of  the 
vagina  in  females. 

III.  VITAL  PROPERTIES  AND  FUNCTIONS  OF  THE  GENITAL  ORGANS  IN  THE  MALE. 

§ 2472.  The  testicles  secrete  the  semen,  and  are  the  most  important 
part  of  the  genital  organs,  since  the  action  of  this  fluid  on  the  body 
of  the  female  can  alone  cause  the  formation  of  a perfect  new  organism. 

This  is  demonstrated  by  sterility  occurring  when  these  organs  are 
extirpated,  are  congenitally  absent  or  diseased,  although  the  other  ge- 
nital organs  are  formed  normally. 

The  semen  is  a whitish  and  strong  smelling  liquid  ; it  is  composed 
in  1000  parts:  of  water  900,  animal  mucilage  60,  phosphate  of  dime 
30,  soda  10.(1) 

The  'testicles  also  perform  an  important  part  in  the  individual  or- 
ganism ; for  when  they  do  not  exist,  or  when  they  have  been  removed, 
the  body  and  the  mind  vary  more  or  less  from  the  normal  state,  the 
larynx  and  the  voice  are  not  developed,  the  beard  does  not  grow,  in 
short  the  individual  does  not  acquire  the  distinctive  characters  of  his 
sex. 

The  semen  is  carried  from  the  testicles  through  the  ductus  deferens 
into  the  seminal  vesicles,  where,  like  all  the  other  fluids  in  their  reser- 
voirs, it  continues  a certain  time,  becomes  perfect,  and  is  concentrated 
by  the  absorption  of  its  aqueous  portion, (2)  and  perhaps  is  somewhat 
modified  by  mingling  with  a fluid  secreted  in  the  parietes  of  the  ve- 
sicles. 

In  fact,  several  distinguished  anatomists,  as  Wharton, (3)  Van 
Horne, (4)  Swammerdam, (5)  and  Hunter, (6)  have  rejected  this  gene- 

(1)  Yauquelin,  Annales  de  chimie,  vol.  ix.,  p.  64. — Berzelius  states  ( Annales  de 
chimie,  vol.  lxxxviii.,  p.  115)  that  the  semen  is  formed  of  a peculiar  animal  matter 
and  of  all  the  salts  of  the  blood. 

(2)  G.  Eitner,  Semen  non  resorhetur,  Berlin,  1820. 

(3)  De  vesiculis  semin alibus  ; in  his  Adenographia,  cap.  xxx.,  p.  208. 

(4)  Prodromus  observationum  suarum  circa  partes  genitales  in  utroque  sexu , 
Leyden,  1668. 

(5)  Miraculum  naturce,  s.  uteri  muliebris  natura,  Leyden,  1672,  p.  10. 

(6)  Observations  on  the  glands  situated  between  the  rectum,  and  bladder,  called 
vésicules  séminales  ; in  the  Observations  on  certain  parts  of  the  animal  economy, 


OF  THE  GENJTAL  SYSTEM, 


429 


rally  admitted  opinion,  and  assert  that  the  seminal  vesicles  do  not  re- 
ceive the  semen,  but  they  only  secrete  a peculiar  fluid  supplied  by  the 
testicles,  and  some  of  them,  as  Wharton,  have  considered  it  as  the 
proper  semen.  They  adduce  the  following  arguments  : 

1st.  The  seminal  vesicles  and  the.  ejaculatory  ducts  have  no  com- 
mon excretory  canal. (1) 

2d.  Their  structure  is  glandular.(2) 

3d.  A liquid  injected  to  the  base  of  the  seminal  vesicle  penetrates 
into  the  ductus  deferens. (3) 

4th.  Several  animals,  particularly  fishes,  have  seminal  vesicles,  but 
no  testicles. (4) 

5th.  The  fluid  contained  in  the  seminal  vesicles  differs  from  the 
semen,  both  in  man  and  animals  ; it  is  much  brighter  and  more  liquid, 
and  has  not  the  peculiar  odor  of  semen. (5) 

6th.  The  fluid  which  sometimes  comes  from  the  urethra,  when  vio- 
lent efforts  are  made  at  stool,  is  very  similar  to  that  found  in  the 
vesicles. (6) 

7th.  In  males  who  have  lost  one  testicle, (7)  or  in  whom  one  of  the 
testicles  does  not  communicate  with  its  seminal  vesicle,  this  latter  and 
even  the  lower  part  of  the  ductus  deferens  of  the  same  side  have  been 
found  not  contracted  or  empty,  but,  on  the  contrary,  larger  and  fuller 
than  that  of  the  opposite  side. (8) 

8th.  When  coition  is  interrupted,  pain  is  felt  in  the  testicle,  and  not 
in  the  seminal  vesicles.(9) 

9th.  The  seminal  vesicles  are  as  full  in  aged  men  and  those  who 
have  long  been  indisposed,  as  in  those  who  die  suddenly,  or  as  in 
young  men.(10) 

10th.  In  several  animals  there  is  no  communication  between  the 
seminal  vesicles  and  the  vasa  deferential  11) 

11th.  In  many  animals,  particularly  in  guinea-pigs,  the  seminal 
vesicles  are  filled  with  fluid  after  coition.(12) 

12th.  We  find  no  traces  of  them  in  several  animals. (13) 

London,  1786,  1792,  p.  31. — Chaptal,  Mém.  où  Von  se  propose  défaire  voir  que  les 
vésicules  séminales  ne  servent  pas  de  réservoir  à la  semence  séparée  des  testicules  ; in 
the  Journal  de  physique,  1787,  p.  101. 

(1)  AVharton,  p.  209. — Van  Horne. 

(2)  Ibid. 

(3)  Swammerdam,  loc.  cit.,  p.  10. 

(4)  Idem,  in  Brugnone,  Mém.  de  Turin , 1786,  p.  619. 

(5)  Hunter,  p.  32,  38,  39. 

(6)  Id.,  p.  33. 

(7)  Id.,  p.  33-36. 

(8)  Id.,  p.  37. 

(9)  Id.,  p.  37. 

(10)  Id.,  p.  37-38.! 

(11)  Id.,  p.  38. 

(12)  Id.,  p.  39. 

(13)  Id.,  p.  40. 


Vol.  III. 


55 


430 


DESCRIPTIVE  ANATOMY. 


§ 2473.  Many  of  these  facts,  however,  are  but  slightly  conclusive, 
or  are  even  incorrect,  so  that  they  may  be  easily  refuted,  and  the  old 
opinion  thus  be  maintained.(l) 

1st.  The  seminal  vesicles  and  the  vasa  deferentia  communicate  in 
the  manner  mentioned  above. 

2d.  The  glandular  structure  of  the  vesicles  only  proves  that  they 
secrete,  and  not  that  they  receive  semen. 

3d.  The  facility  with  which  liquids  injected  into  them  penetrate  into 
the  ductus  deferens  proves  exactly  that  with  which  the  semen  passes 
from  these  latter  within  them. 

4th.  The  organs  of  fishes  said  to  be  seminal  vesicles  are  in  fact  tes- 
ticles. 

5th.  The  difference  between  the  liquid  in  the  vesicles  and  the  semen 
emitted,  may  depend  on  a mixture  of  their  proper  secretion  with  that 
of  the  testicles.  Farther  the  semen  ejaculated  is  composed  of  the  fluid 
of  the  testicles  united  with  that  of  the  seminal  vesicles,  the  prostate 
gland,  the  glands  of  Cowper,  and  the  mucous  membrane  of  the 
urethra. 

6th.  It  does  not  follow  from  this  that  the  liquid  ejaculated  has  not 
passed  from  the  testicles  into  the  seminal  vesicles.  Possibly,  the  fluid 
expelled  during  efforts  to  go  to  stool,  comes  from  the  prostate  gland 
and  even  from  other  parts,  as  a similar  thing  occurs  in  dogs  which 
have  no  seminal  vesicles. (2) 

7th.  Possibly  this  effect  was  accidental,  which  is  more  probable, 
since  the  gall-bladder,  when  the  bile  is  prevented  by  a calculus  from 
entering,  is  often  distended  to  a great  degree  by  the  mucus  which  it 
secretes. 

8th.  This  opinion  is  often  opposed,  at  least  by  experience.  Farther 
when  this  is  not  the  case  it  would  only  prove  that  the  venereal  or- 
gasm increases  also  the  action  of  the  testicles,  and  that  the  semen 
emitted  comes  not  only  from  the  vesicles,  but  also  from  the  glands 
themselves. 

9th.  The  assertion  is  not  correct,  and  proves  nothing.  Even  Hun- 
ter admits  that  the  seminal  vesicles  take  part  in  the  genital  act,  so  that 
their  uniform  depletion  under  different  circumstances  is  not  more  sur- 
prising, whether  the  fluid  comes  from  the  testicles,  or  is  secreted  by 
the  vesicles. 

10th.  The  absence  of  the  seminal  vesicles  in  several  animals,  does 
not  prove  that  the  semen  is  not  introduced  into  the  reservoirs  when 
they  exist.  Farther,  a communication  between  the  vesicles  and  the 
vasa  deferentia,  really  exists  in  several  animals  where  it  is  not  admit- 

(1)  De  Graaf,  Partium  gcnitalium  defensio,  Leyden,  1673.— Needham,  Croone, 
and  King-,  in  Birch,  Hist,  of  the  ray.  society , vol.  iii.,  p.  103. — Brugnohe,  Observa- 
tions anatomiques  sur  tes  vésicules  séminales  tendantes  à en  confirmer  l’usage  ; in 
the  Mém.  de  Turin , 1786-1787. — Soemmerring,  Anmerkungen  über  Hunter's  Auf- 
satz ; in  Blumenbach,  Medic.  Bibi .,  vol.  iii.,  p.  87. 

(2)  Brugnone,  loc.  cit.,  p.  622. 


OF  THE  GENITAL  SYSTEM. 


431 


t ed  by  Hunter,  as  the  guinea-pig  and  the  horse,  while  the  pretended 
seminal  vesicles,  which  according  to  others  do  not  communicate  with 
the  excretory  passages  of  the  vesicles,  are  protsate  glands. 

1 1th.  There  is  no  proof  that  a portion  of  the  contents  of  the  seminal 
vesicles  does  not  escape  during  coition. 

12th.  It  does  not  follow  that  the  semen  does  not  run  at  all  in  the 
seminal  vesicles  in  those  animals  which  are  provided  with  these  reser- 
voirs. 

13th.  In  whatever  position  the  body  may  be,  the  liquid  injected 
through  the  ductus  deferens,  arrives  sooner  into  the  vesicle  than  into 
the  ejaculatory  passage.(l) 

14th.  The  substances  injected  into  the  vesicle  generally  emerge 
through  the  ejaculatory  passage  before  arriving  at  the  ductus  deferens, 
and  frequently  do  not  penetrate  at  all  into  the  latter. (2) 

15th.  The  air  and  sounds  introduced  through  the  orifice  of  the  duc- 
tus deferens,  easily  penetrate  into  the  vesicle,  but  with  difficulty  into 
the  ejaculatory  passage.  Notwithstanding  this  refutation  of  Hunter’s 
opinion,  we  cannot  deny  that  the  proper  secretion  of  the  seminal  ve- 
sicles seems  to  contribute  powerfully  to  elaborate  the  semen. 

§ 2474.  The  semen  comes  into  the  urethra  and  directly  into  the 
prostate  gland,  where  it  mingles  with  a more  serous  and  yellowish 
white  fluid  secreted  by  this  gland,  and  which  also  contributes  to  per- 
fect it.(3) 

On  leaving  this  point  it  is  sent  into  the  penis  by  the  action  princi- 
pally of  the  bulbo-cavernosi  muscles. 

§ 2475.  The  penis  possesses  in  a great  degree  the  power  of  enlarg- 
ing and  lengthening  by  the  excitement  of  the  venereal  passion.  It  also 
becomes  hard  and  stiff,  which  depends  undoubtedly  on  the  dilatation 
and  tension  of  its  fibrous  envelop. 

Its  power  of  erection  depends  on  the  peculiar  arrangement  of  its 
vessels  ; when  erected  it  can  enter  into  the  vagina  of  the  female; 
it  fills  this  canal  more  or  less  perfectly,  and  injects  the  semen  into  the 
internal  organs  of  generation,  particularly  the  uterus.  The  erection 
of  the  penis  depends  on  the  great  excitement  of  the  nervous  action, 
either  in  the  whole  system  or  in  the  nerves  of  the  penis,  which  are  pro- 
portionally very  large  ; a greater  quantity  of  blood  is  then  carried  into 
it  by  the  arteries,  and  is  not  resumed  by  the  large  and  numerous  veins  of 
the  organ,  as  rapidly  as  it  flows  into  it.  It  has  been  asserted  that 
the  phenomenon  of  erection  ought  not  be  explained  thus  by  the  accu- 
mulation of  blood, (4)  but  this  opinion  is-  completely  refuted  by  the  ex- 
periments,(5)  in  which,  on  cutting  the  penis  when  erected,  after 
tying  its  base,  the  venous  plexuses  are  found  gorged  with  blood. 

(1)  De  Graaf,  loc.  cit.—  Brugnone,  p.  620. 

(2)  Brugnone,  loc.  cit. 

(3)  Haller,  El.  phys.,  vol.  viii.  p.  454. — Brugnon e,  loc.  cit. 

(4)  Langguth,  in  Schumann,  Devi  imaginationis  in  feet  um,  Wittemberg,  1790. 

(5)  R.  de  Graaf,  De  virorum  organis  ; in  Opp.  omn .,  p.  84. — Swammerdam, 
Prodr.  obs.  de  part,  genit.,  p.  13  — Th.  Roose,  lieber  das  Anschwellungsvermogen 


432 


DESCRIPTIVE  ANATOMY. 


§ 2476.  The  first  changes  which  cause  the  emission  of  semen,  un- 
doubtedly take  place  in  the  glans,  since  it  possesses  the  most  nerves, 
and  is  the  most  sensible  part,  not  only  of  the  penis,  but  of  the  whole 
genital  system.  The  excitement  of  the  nervous  action  in  this  part  is 
extended  to  the  whole  nervous  system,  particularly  to  the  nerves  of  the 
genital  organs,  quickens  the  secretion  of  the  testicles,  the  seminal  ve- 
sicles, and  the  other  glands,  and  causes  convulsive  motions  in  the 
bulbo-cavernosi  muscles,  which  compress  the  spermatic  fluid  when  it 
arrives  at  the  posterior  part  of  the  urethra,  and  throw  it  by  jets  into 
this  canal,  which  is  rendered  straight  by  the  erection  of  the  penis. 

II.  MAMMAE. 

§ 2477.  The  mammcc{  1)  are  the  accessory  parts  of  the  genital  sys- 
tem, which  in  man  and  in  all  true  mammalia,  establish  a natural  rela- 
tion between  the  organism  of  the  mother  and  that  of  the  child,  by 
means  of  the  milk  which  they  secrete,  which  continues  during  the 
early  periods  of  life.  In  birds,  and  perhaps  also  in  some  reptiles,  there 
exists  a similar  connection  between  the  mother  and  the  offspring, 
which  continues  a longer  or  shorter  period  after  the  birth  of  the  latter. 
But  in  these  animals  it  does  not  occur  by  a special  organ,  having  the 
power  of  secreting  a peculiar  nutritious  fluid.  It  is  only  by  a portion 
of  the  intestinal  canal,  the  crop  ( ingluvies ),  which  undergoes  about 
this  period  a change  analogous  to  that  which  occurs  in  the  mammae, 
but  which,  however,  serves  for  the  mother  and  the  offspring. 

I.  NUMBER. 

§ 247S.  The  mammae  are  two  in  number  ; they  are  glandular  or- 
gans, conglomerate  glands. 

Although  regularly,  they  fulfill  their  function  only  in  the  female, 
they  occur  also  in  the  male,  where  they  are  much  less  developed  ; the 
mammae  of  the  male,  however,  are  sometimes  as  large,  and  their 
secretion  as  abundant  as  those  of  the  female. 

des  männlichen  Gliedes  im  gesunden  Zustande;  in  Physiologische  Untersuchun- 
geni,  Brunswick,  1796,  p.  17. 

(1)  A.  Nuch,  Adenographia  curiosa,  Leyden,  1691,  c.  ii. — Mencelius,  De  struc- 
tura mammarum,  Leyden,  1720. — Guntz,  De  mammarum  fabrica  et  lactis  sccretione, 
Leipsic,  1734. — Bcehmer,  De  ductibus-  mammarum  lactiferis , Halle,  1742. — Kcelpin, 
De  structura  mammarum,  Gripswald,  1764. — Crusius,  De  mammarum  fabrica  et 
lactis  secretione , Leipsic,  1785. — Covolo,  De  mammis  ; in  Santorini,  Tabul,  septemd., 
p.  92-110. — Girard,  De  mammarum  structura  ; ibid.,  p.  110-116. — A.  Joannides,  De 
mammarum  physiologia,  Halle,  1801. 


OF  THE  MAMMARY  GLANDS. 


433 


II.  SITUATION  AND  FORM. 

§ 2479.  They  are  situated  opposite  to  one  another,  one  on  each 
side,  on  the  anterior  face  of  the  chest,  and  the  region  which  they  oc- 
cupy in  the  female  is  termed  the  mammary  region  ( regio  mamma). 
The  glandular  substance  which  forms  their  base,  is  surrounded  by  a 
great  quantity  of  fat,  which  gives  them  a semicircular  form.  Their 
base,  however,  is  not  perfectly  circular,  but  rather  eliptical. 

It  extends  particularly  upward  and  outward,  and  often  to  the  region 
of  the  axilla  ; it  is  more  circular  below  and  inward.  It  extends  from 
the  third  to  the  seventh  rib,  and  covers  most  of  the  pectoralis  major 
muscle  ; but  not  unfrequently  the  most  external  portion  of  its  lower 
edge  covers  also  a portion  of  the  serrât  us  magnus  muscle. 

The  edge  of  the  mammas  is  not  smooth  in  every  part,  nor  is  its 
thickness  uniform.  In  those  females  wrho  have  borne  several  chil- 
dren, it  presents  inequalities,  because  the  gland  enlarges  irregularly 
outward,  so  that  irregular  prolongations  leave  its  edge. 

Nor  is  the  circumference  of  the  mammae  smooth  in  every  part. 

It  presents  in  every  part  analogous  prolongations,  differing  in  form, 
size,  and  direction,  which  render  its  surface  uneven,  and  leave  between 
them  greater  or  less  depressions.  The  lower  and  internal  part  of  these 
glands  is  much  thicker  than  the  upper  and  external. 

A little  below  the  centre  of  the  mammæ,  in  its  thickest  portion,  we 
perceive  a more  or  less  prominent  eminence,  termed  the  nipple  ( ma - 
milia,  papilla  mamma),  which  is  surrounded  by  a more  colored  circle, 
and  the  level  of  which  is  often  below  that  of  the  common  integuments. 
This  circle,  the  skin  of  which  is  thinner  and  finer  than  that  of  the  rest 
of  the  nipple,  is  termed  the  areola  ( areola  mamma.) 

III.  TEXTURE. 

§ 2480.  The  texture  of  the  mammæ  is  not  the  same  in  every  part. 
Almost  all  its  substance  is  composed  of  small  reddish  white  grains 
(acini),  which  are  distinguished  very  easily  in  females  during  the 
period  of  lactation.  These  grains  are  about  the  size  of  a millet  seed. 
They  are  composed  in  turn  of  smaller  vesicles,  not  rounded,  but  oblong, 
which  are  grooved  and  ranged  in  rays.  They  are  united  by  cellular 
tissue  and  vessels. 

These  grains  do  not  exist  toward  the  centre,  in  the  areola,  where  we 
find  only  a fibrous  and  whitish  substance,  which  is  decomposed  by 
maceration,  into  a tissue  of  canals,  which  are  united  by  cellular  sub- 
stance. 

§ 2481.  These  canals  are  the  extremities  of  the  milk-ducts  (ductus 
galactophori,  s.  lactiferi).  The  latter  arise  by  as  many  small  roots 
as  there  are  grains,  and  gradually  unite  in  larger  trunks,  which  finally 
terminate  in  the  centre  of  the  nipple,  behind  the  areola  by  conical,  dila- 


434 


DESCRIPTIVE  ANATOMY. 


tâtions  or  sinuses.  Tiie  excretory  passages  of  the  mammary  gland 
are  larger  than  in  any  other  conglomerate  gland.  The  size  of  the 
trunks  varies  according  as  they  receive  a greater  or  less  number  of 
branches.  Many  are  very  small.  The  number  of  great  branches 
which  finally  unite  to  give  rise  to  one  trunk,  varies  from  four’ to  twelve. 
The  extent  of  the  central  sinus  is  also  in  direct  ratio  with  the  size  of 
the.  trunks.  Sometimes  these  dilatations  are  from  two  to  three  lines 
broad  ; but  they  are  always  short,  compactly  arranged  at  their  internal 
extremity,  and  a little  separated  at  their  external.  The  internal  ex- 
tremity of  each  suddenly  contracts  into  a very  small  canal,  which 
passes  in  a straight  line  through  the  centre  of  the  nipple  to  its  summit, 
contracts  a little,  rarely  enlarges  in  some  part  of  its  extent,  and  finally 
opens  on  the  surface  of  the  nipple  by  a very  small  orifice.  All  these 
small  canals,  which  are  about  the  breadth  of  a finger  long,  are  united 
very  intimately  by  mucous  tissue.  Only  one  canal  comes  from  each 
dilatation. 

§ 2482.  The  whole  milk-passage,- which  consequently  includes  the 
carrying  portion,  the  dilatation,  and  the  excretory  canal,  is  formed  by 
a soft,  thin,  and  transparent  membrane,  similar  to  a mucous  membrane. 

These  passages  are  not  exposed  in  most  of  their  course.  The 
trunks  are  often  situated  very  deeply  in  the  substance  of  the  gland, 
and  those  even  which  proceed  at  first  on  its  surface,  especially  those 
which  come  from  the  prolongations  mentioned  above,  penetrate  deeply. 

They  are  formed  by  the  successive  union  of  branches  and  twigs, 
which  always  diminish  in  caliber  ; but  they  do  not  communicate  by 
anastomosing  branches.  Nuck(l)  and  Yerheyen(2)  have  in  fact  de- 
scribed and  figured  very  large  anastomosing  branches,  situated  in  the 
areola,  directly  at  the  base  of  the  nipple,  which  go  from  one  milk-pas- 
sage  to  another,  and  thus  form  a ring  ; but  no  other  person  has  found 
them,  and  we  also  have  been  unsuccessful,  although  we  have  carefully 
sought  for  them  several  times.  This  anastomosing  circle  is  not  only 
invisible,  but  also  the  injection  pushed  into  one  milk-passage  never  flows 
into  another,  which  would  be  the  case  if  the  anastomoses  really  existed. 
The  milk-passages  are  not  provided  with  valves  as  several  observers 
have  stated.  Farther,  the  existence  of  these  valves  is  refuted  by  the 
facility  with  which  injections  enter  through  the  nipple.  Sometimes, 
however,  we  observe  fluids,  particularly  mercury,  injected  through  an 
opening  in  one  milk-passage,  return  by  another,  but  always  under  cir- 
cumstances which  prove  the  communication  exists  between  the  most 
minute  ramifications  of  the  passages.  Probably  the  anastomoses,  like 
the  ducts  themselves,  do  not  dilate  sufficiently  to  produce  this  result 
until  toward  the  end  of  pregnancy,  and  during  the  period  of  lactation. 
But  the  researches  of  Meckel(3)  on  the  mammae  of  females  dying  in 

(1)  Adenographia  curiosa,  Leyden,  1691,  p.  1G.  fig1 2 3.  2. 

(2)  An  at.  corp.  hum.  vol.  i.  tab.  xviii.  fig.  4. 

(3)  J.  F.  Meckel,  Nova  expérimenta  el  observât,  de  sinibus  venarum,  Berlin,  1772, 

{ 4,  5,  9. 


OF  THE  MAMMARY  GLANDS. 


435 


parturition,  demonstrate  their  existence  as  positively,  as  it  refutes  that 
of  the  anastomoses  admitted  by  Nuck  and  Veiheyen.  We  have  also 
obtained  the  same  results  under  similar  circumstances. 

§ 2483.  Notwithstanding  these  small  anastomoses,  the  mammas  is 
composed  of  as  many  distinct  and  separate  glands  as  there  are  milk 
passages.  This  is  demonstrated  by  injecting  each  canal  with  differ- 
ently colored  fluids,  for  the  injections  blend  in  no  part,  and  the  different 
glands  can  be  detached  and  separated. 

§ 2484.  The  number  of  the  milk-passages,  consequent^  also  that 
of  the  conglomerate  glands,  varies  even  in  the  two  mammæ  of  the  same 
female.  The  old  anatomists  have  reduced  the  number  too  much,  as 
they  estimated  them  only  at  six  or  seven  ; Haller,  Walter,  Covolo, 
and  ourselves,  have  never  found  less  than  fifteen.  Our  dissections, 
however,  have  convinced  us  that  Walter  was  mistaken  in  saying  that 
there  are  never  more  than  fifteen,  sometimes  we  have  found  more  than 
twenty,  as  have  also  Haller  and  Covolo.  Their  greatest  number  is 
twenty-four,  according  to  Covolo.  These  that  are  situated  highest, 
and  most  on  the  outside,  are,  as  Waiter  justly  remarks,  very  small 
and  very  narrow,  which  agrees  with  the  less  degree  of  thickness  of  the 
mammary  gland  at  its  upper  part. 

§ 2485.  Besides  the  orifices  of  these  milk-passages  on  the  summit 
of  the  nipples,  we  find  in  the  areola  also,  others  which  generally 
occupy  the  extremities  of  the  tubercles  ; these  are  arranged  irregu- 
larly, and  two  or  three  of  them  sometimes  unite  in  one. 

Several  anatomists  have  considered  these  tubercles  as  simple  seba- 
ceous glands.  Bidloo  and  Morgagni  have  sometimes  seen  coming 
from  them  a limpid  liquid  ; Morgagni,  Winslow,  and  Covolo  have  also 
seen  them  supply  a more  or  less  thick  milk  in  females,  during  lacta- 
tion, and  the  last  phenomenon  has  been  observed  also  in  males-  by 
Morgagni.  The  quantity  and  the  nature  of  the  fluid  coming  from 
them,  depends  on  the  length  of  time  which  has  elapsed  between  the 
repast  and  the  time  of  nursing,  so  that  several  hours  after  the  repast, 
or  when  the  child  has  not  nursed  for  a longtime,  the  milk  is  abundant, 
while  in  the  opposite  case,  some  drops  of  a brighter  liquid  slowly 
dribble  out. 

These  tubercles  are  entirely  different  from  sebaceous  glands.  We 
find  numerous  sebaceous  glands  on  the  areola  and  the  nipple,  and  they 
never  rise  above  the  surface  like  the  tubercles,  on  which  we  often  ob- 
serve several.  An  attentive  examination  shows  in  several  of  these  tu- 
bercles, one,  and  sometimes  even  four  small  excretory  ducts,  leading  to 
small  glands,  which  are  precisely  of  the  same  nature  as  those  we  have 
mentioned,  but  which,  however,  are  smaller  ; they  are  situated  directly 
under  the  skin  of  the  areola,  and  are  united  with  each  other  and  with 
the  body  of  the  gland,  by  cellular  tissue.  Sometimes,  in  fact,  but 
rarely,  these  small  glands  open  into  the  portion  of  the  integuments  of 
the  mammæ,  which  directly  covers  the  circumference  of  the  areola. 
They  vary  in  number  and  size.  There  are  generally  from  five  to  ten 
tubercles. 


436 


DESCRIPTIVE  ANATOMY. 


Thus  the  small  glands  and  the  tubercles  in  which  their  excretory 
ducts  terminate,  are  arranged  in  regard  to  the  mammary  gland,  pre- 
cisely in  the  same  manner  as  the  sublingual  glands  or  the  buccal  and 
the  labial  glands,  are  in  regard  to  the  parotid  and  the  submaxillary, 
and  they  cannot,  at  least  in  our  opinion,  be  regarded  as  anomalies,  as 
Hildebrandt  thinks  them.(l) 

§ 2486.  The  mammary  gland  is  situated  in  a more  or  less  abundant 
adipose  tissue,  which  does  not  form  a continuous  layer  as  in  every 
other  part,  for  it  enters  between  the  depressions  which  we  have  men- 
tioned above,  and  even  contrary  to  what  occurs  in  the  other  glands,  it 
penetrates  deeply  into  the  substance  of  the  organ,  while  there  is  none 
at  its  base.  We  find  no  fat  in  the  nipple  nor  behind  the  areola  ; this 
fat  is  more  firm  and  yellowish  than  in  most  of  the  other  regions  of  the 
body.  The  mucous  tissue  which  contains  it,  also  penetrates  into  all 
the  spaces  between  the  different  glands.  It  condenses  on  the  surface 
of  the  organ  in  a special  sheath,  nearly  similar  to  those  which  surround 
the  muscles. 

Haller  asserls(2)  that  he  has  frequently  seen  milk-passages  arise 
from  the  fat,  which  afterwards  penetrated  into  it.  Covolo  and  our- 
selves have  seen  nothing  like  this.  We  have  every  reason  to  think 
that  Haller  is  mistaken,  and  that  his  error  must  be  attributed  to  the 
existence  of  the  prolongations  mentioned  above. 

§ 2487.  The  vessels  of  the  mammae  arise  from  the  external  thoracic 
vessels.  Their  nerves  come  from  the  third  and  fourth  cervical,  and 
from  the  five  or  six  superior  dorsal  nerves. 

IV.  FUNCTIONS. 

§ 2488.  The  function  of  the  mammary  gland  is  to  secrete  the  milk. 
In  the  normal  state  this  secretion  does  not  begin  until  toward  the  end 
of  gestation.  Its  history  will  be  more  in  place  after  that  of  the  pheno- 
mena produced  by  coition. 


ARTICLE  SECOND. 

PERIODICAL  DIFFERENCES  IN  THE  ORGANS  OF  GENERATION. 

§ 2489.  Until  the  sixteenth  week  there  is  no  trace  of  the  genital 
organs.  When  they  appear  they  are  formed  precisely  after  the  same 
type  in  all  fetuses  ; their  form,  volume,  and  situation  are  the  same, 
and  there  is  consequently  no  distinction  of  sex.  The  internal  genital 
organs  are  formed  ; 

(1)  Lehrbuch  der  Anatomie  des  Menschen , vol.  iii.  p.  339. 

(2)  El.  phys .,  vol.  vii.,  p.  8. 


OF  THE  GENITAL  SYSTEM. 


437 


1st.  Of  two  very  elongated  and  narrow  parts,  oblique  from  without 
inward  und  from  above  downward,  situated  very  high  out  of  the  pelvis, 
and  which  afterward  become  either  the  te'sticles  or  ovaries. 

2d.  Of  two  canals  which  are  not  much  narrower,  but  which  are 
longer  and  thicker,  proceed  beyond  them  above,  and  descend  on  their 
outer  side.  They  produce  either  the  tubes,  or  the  epidydimi  and  the 
excretory  organs  of  the  semen,  and  unite  out  of  the  pelvis  in  a common 
median  duct,  which  becomes  either  the  uterus  and  vagina,  or  the 
prostate  gland,  seminal  vesicle,  and  posterior  part  of  the  urethra. 

3d.  Of  a considerable  triangular  body,  a little  enlarged  at  its  ante- 
rior extremity,  situated  first  at  the-  lower  part  of  the  anterior  wall  of 
the  abdomen,  and  which  afterward  hangs  loosely  forward.  This  body 
is  formed  of  two  halves,  separated  by  a fissure  which  proceeds  along 
its  lower  face  ; it  afterward  forms  the  penis  or  clitoris. 

4th.  There  is  soon  developed  on  each  side  of  this  last  body  a fold  of 
skin,  which  is  directed  from  before  backward.  These  two  folds  are 
not  united  posteriorly.  They  change  into  the  scrotum,  or  the  ex- 
ternal labia. 

§ 2490.  Home,(l)  Autenrieth,(2)  and  Ackermann(3)  had  already 
admitted  this  primitive  identity  of  the  genital  organs  in  all  individuals, 
although  they  indicated  perhaps  less  exactly  and  precisely  the  cha- 
racters of  the  primitive  form,  and  the  manner  in  which  the  differences 
occur. 

As  all  the  fetuses  at  this  period,  which  we  have  compared  and  they 
are  at  least  fifteen,  present  exactly  the  formation  described,  it  is  more 
correct  to  consider,  as  is  generally  done,  the  raphe  of  the  scrotum  and 
penis  as  a mark  of  the  separation  primitively  existing,  and  which  gra- 
dually disappears  by  the  closing  of  the  fissure  from  behind  forward, 
than  to  regard  it,  with  Autenrieth,  as  proving  a tendency  to  this  sepa- 
ration which  really  occurs  only  in  the  female.  Thus  we  have  already 
said  for  a long  time,  reasoning  from  the  facts  observed  by  us,  that  the 
genital  organs  are  formed  after  the  same  type,  particularly  after 
that  of  the  female. (4) 

We . have  already  established  from  observation  that  their  character 
is  still  more  similar  to  that  of  the  female  in  all  fetuses, (5)  and  Tiede- 
mann has  confirmed  this  result,  describing  very  exactly  several  fetuses 
very  near  the  moment  of  then  formation.(6) 

(1)  Phil,  tram.,  1790. 

(2)  Infantis  androgyni  hisloria,  Jena,  1805,  p.  53. 

(3)  Ueber  die  Verschiedenheit  beider  Geschlechter  ; in  Reil,  Archiv,  für  die  Phy- 
siologie, vol.  vii.,  p.  88. 

(4)  Abhandlungen  aus  der  menschlichen  und  vergleichenden  Anatomie , 1806,  vol. 
ii.  We  have  there  described  six  fetuses  of  this  age. — Beytruge  zur  vergleichenden 
Anatomie,  1808,  vol.  i.,  part  i.,  no.  5.  We  have  there  described  twelve  fetuses  of  this 
age. 

(5)  Beyträge  zur  vergleichenden  Anatomie,  vol.  ii.,  pt.  ii.,  p.  170,  Leipsic,  1812. 

(6)  Anatomie  der  kopflosen  Missgeburten,  1813,  p.  80. 

Vol.  III.  56 


438 


DESCRIPTIVE  ANATOMY. 


These  phenomena  are  curious  in  two  respects  : 

1st.  There  are  generally  no  genital  organs  in  most  of  the  lower 
animals,  or  at  least  those  which  exist  correspond  to  the  genital  organs 
of  the  female  in  those  where  there  are  two  sexes,  so  that  in  this  re- 
spect also  the  same  law  prevails  in  the  development  of  the  fetus  and 
that  of  the  aminal  series. 

2d.  This  explains  also  the  greater  frequency  of  female  monstrosi- 
ties. 

Farther  the  great  size  of  the  clitoris,  the  -smallness  of  the  uterus, 
and  perhaps  also  a real  connection  between  the  ovaries  and  the  Fal- 
lopian tubes  : and  secondly,  the  situation  of  the  testicles  in  the  abdo- 
men, establish  still  longer  between  the  two  sexes  a similarity  which 
afterward  does  not  exist. 

From  the  third  month  of  pregnancy,  however,  the  ovaries  are  al- 
ways smaller  than  the  testicles  ; they  are  situated  more  horizontally, 
and  the  penis  differs  from  the  clitoris,  as  the  fissure  has  disappeared 
from  its  surface. 


1.  GENITAL  ORGANS  OF  THE  FEMALE. 

§ 2491.  The  development  of  the  genital  organs  of  the  female  differs 
particularly  from  that  of  the  genital  organs  of  the  male,  in  the  less 
number  of  successive  periods  through  which  it  passes. 

I.  OVARIES. 

§ 2492.  At  first  the  ovaries/ 1)  proportionally  speaking,  and  parti- 
cularly in  regard  to  the  other  genital  organs,  are  much  larger  than 
they  are  subsequently.  They  form  for  a long  time  most  of  these 
organs,  although  when  the  difference  of  sex  is  more  evident,  they  are 
proportionally  smaller  than  the  testicles,  and  this  difference  even  is 
one  of  their  principal  distinctive  characters. 

At  about  the  middle  of  the  third  month  of  fetal  existence,  and  when 
the  embryo  is  two  inches  long,  they  are  hardly  a line  and  one  quarter 
in  length,  less  than  half  a line  high,  and  a little  less  than  one  third  of  a 
line  thick.  In  the  full-grown  fetus  they  weigh  between  five  and  ten 
grains.  They  are  situated  almost  horizontally  far  above  the  small 
pelvis,  but  from  their  horizontal  direction  their  upper  or  external  ex- 
tremities do  not  rise  as  high  as  the  testicles  in  the  male  fetuses  of  the 
same  age,  so  that  they  are  very  far  from  touching  the  kidneys. 

Their  internal  extremities,  on  the  contrary,  are  so  near  each  other 
that  only  the  rectum  exists  between  them,  which  is  at  this  time  very 
narrow,  so  that  the  intestine  does  not  completely  separate  them.  Their 


(1)  Roaenmullei-,  De  ovariis  embryonen  et  fœtuwn,  Leipsic,  1802. 


OF  THE  GENITAL  SYSTEM. 


439 


form  is  very  elongated,  narrow,  and  prismatic  ; ihey  become  rounded 
only  at  puberty,  and  they  are  then  thicker  in  proportion  to  their  length. 
Their  capsule  is  very  thin,  not  only  in  the  full-grown  fetus,  but  also 
during  all  the  early  years  of  life. 

Their  tissue  is  more  simple  until  the  middle  of  the  first  year  of  exist- 
ence. In  this  respect  we  have  as  yet  been  unable  to  discover  any 
trace  of  the  vesicles  of  Graaf  before  the  age  of  six  months,  when  these 
vesicles  form,  and  they  arè  then  proportionally  very  large. 

In  the  latter  half  of  the  existence  of  the  female  the  ovaries  begin  to 
grow  harder  and  to  waste.  They  lose  their  smoothness,  and  their 
surface  appears  more  or  less  uneven,  because  the  depressions  observed 
in  it  are  changed  into  considerable  cavities. 

This  effect  depends  principally  on  the  disappearance  of  the  paren- 
chyma ; but  the  vesicles  also  change  at  the  same  time  ; they  diminish, 
their  membranes  become  thicker,  and  finally  their  cavity  disappears, 
and  they  are  converted  into  yellowish  or  blackish,  or  often  into  fibro- 
cartilaginous or  osseous  bodies. 

The  ovaries  wasta  so  much  in  females  advanced  in  life  that  they 
sometimes  disappear. entirely,  and  the  place  they  occupy  is  indicated 
only  by  the  vessels.  Frequently  then  they  weigh  only  twenty  grains. 

§ 2493.  According  to  several  writers,  as,  for  instance,  Malpighi, (1) 
Vallisneri,(2)  Santorini, (3)  Bertrandi,(4)  Brugnone,(5)  and  Buffon,(6) 
the  formation  of  the  yellow  bodies  ( corpora  lutea ) belongs  also  to  the 
history  of  the  development  of  the  ovaries,  because  they  have  been  found 
not  only  in  virgins,  but  in  the  young  females  of  animals.  But  it  is 
not  well  proved  that  these  bodies  have  the  same  origin  and  the-  same 
use  as  the  common  yellow  bodies  ; and  it  is  extremely  probable  that 
their  formation  has  been  preceded  by  an  increase  in  the  activity  of  the 
genital  organs,  arising  from  some  cause.  We  think  it  more  proper  to 
refer  the  examination  of  them  to  the  chapter  on  the  changes  produced 
in  the  genital  parts  by  conception. 

II.  TUBES,  UTERUS,  AND  VAGINA. 

§ 2494.  The  Fallopian  tubes,  the  uterus,  and  the  vagina,  form  at 
first  only  a single  canal,  cleft  at  its  upper  part,  which  is  uniformly 
broad,  and  which  extends  uninterruptedly  from  the  abdominal  extre- 
mity of  the  tubes  to  the  external  orifice  of  the  vagina. 

(1)  Diss.  ep.  var,  largum  ; in  the  Opp.  omv.,  Leyden,  1687,  vol,  ii.,  p.  223. 

(2)  Von  der  Erzeugung  des  Menschen  und  der  Thiere , pt.  ii.  c.  iii.,  p.  262,  319. 

(3)  Obs.  anat.,  c.  xi.,  p.  223. 

(4)  De  glandules  ovarii  corporibus  ; in  the  Mise.  Taur.,  vol.  i.,  p.  104. 

(5)  Dt  ovarii  eorumque  corporibus  lut  eis  ; in  the  Mim,,  de  Turin,  1790,  p.  393. 

(6)  Hist,  nat.,  vol.  ii.,  p.  203. 


440 


DESCRIPTIVE  ANATOMY. 


A.  TUBES. 

§ 2495.  The  tubes  are  at  first  proportionally  much  thicker  and 
longer  than  they  are  subsequently. 

They  descend  at  first  very  obliquely  from  without  inward  on  the 
outside  of  the  ovaries,  to  which  they  are  directly  united,  but  extend 
much  beyond  their  upper  extremity.  Until  the  third  month  they  are 
united  at  an  acute  angle  at  their  lower  and  inner  extremities  in  a small 
and  median  perpendicular  mass,  which  is  at  first  very  narrow,  but 
which  gradually  becomes  a little  wider,  and  represents  the  uterus. 
They  are  not  tortuous  until  the  fourth  month. (1)  At  five  months 
only  they  begin  to  exhibit  curves,  which  are  at  first  very  indistinct, 
and  gradually  enlarge,  so  that  at  eight  months  and  at  birth  they  are 
more  tortuous  than  in  the  adult  : an  arrangement  which  they  preserve 
also  during  the  first  years  of  life.  They  seem  at  first  to  terminate  in 
a cul-de-sac  and  by  an  enlargement. 

Their  abdominal  extremity  seems  to  open  at  the  fourth  month,  but 
the  fimbriated  ends  are  not  developed  till  afterward.  Their  cavity  is 
always  much  larger  proportionally  the  younger  the  fetus  is,  and  it  is 
always  found  without  difficulty  whenever  it  is  sought  for. (2) 

Bettveen  the  tubes  and  the  ovaries  in  the  fold  of  the  peritoneum 
extremely  curious  vessels(3)  exist,  not  only  in  the  embryo  and  the 
fetus,  but  also  during  the  first  years  of  life  ; these  cannot  be  injected 
through  the  tubes  nor  through  the  ovary,  so  that  we  cannot  consider 
them  as  establishing  a communication  between  the  cavity  of  the 
former  and  the  substance  of  the  latter  ; they  are  so  similar  in  their 
number,  situation,  and  form,  to  the  vasa  deferentia  of  man,  that  we 
must  consider  them  at  least  as  tending  to  the  formation  of  these  pas- 
sages and  the  epidydimis. 

The  primitive  form  of  the  abdominal  extremity  of  the  tube,  however, 
allows  us  to  conjecture,  and  with  some  probability,  that  they  commu- 
nicate first  with  the  ovarjq  but  that  the  communication  is  probably 
closed  when  the  abdominal  extremity  of  the  tube  opens,  and  conse- 
quently when  a new  passage  forms. 

B.  UTERUS. 

§ 2496.  The  uterus  is  at  first,  and  usually  even  until  the  end  of  the 
third  month  at  least,  much  broader,  and  has  two  horns.  " The  horns 
are  as  much  longer  and  their  angle  of  union  is  more  acute  the  younger 

(1)  The  general  opinion  then  that  the  tubes  are  always  tortuous  in  the  fetus  is 
not  exactly  correct.  Their  primitive  straightness  is  very  important,  on  ac- 
count of  the  analogy  it  establishes,  first  between  them  and  the  intestinal  canal  during 
the  early  periods  of  existence,  and  also  between  them  and  the  oviducts  of  several 
animals. 

(2)  Hirschel  and  Roesslein  have  asserted  the  contrary,  but  they  are  wrong. 

(3)  Rosenmuller,  loc.  cit. 


OF  THE  GENITAL  SYSTEM. 


441 


the  fetus  is.  But  when  this  angle  entirely  disappears,  the  uterus 
seems  to  have  two  horns.  At  first  it  is  equally  broad  in  every  part, 
and  perfectly  smooth  ; there  is  no  prominence  either  on  the  outside  or 
on  the  inside  which  separates  it  from  the  vagina.  It  begins  to  enlarge 
at  its  upper  extremity  about  the  end  of  the  fourth  month.  This  phe- 
nomenon depends  on  the  disappearance  of  the  horns  which  existed  at 
first,  and  which  are  replaced  by  a single  cavity.  But  this  upper  part 
is  much  smaller  the  younger  the  fetus  is,  whence  the  neck  is  larger 
than  the  body  in  the  same  proportion. 

The  body  gradually  increases,  so  that  about  the  period  of  puberty 
the  uterus  loses  its  almost  cylindrical  form,  and  becomes  pyriform. 
The  length  of  the  body  is  only  one  fourth  of  that  of  the  whole  organ 
in  the  full-grown  fetus  ; it  is  only  one  third  at  thirteeen  years  old,  and 
does  not  form  one  half  till  after  puberty. 

At  the  same  time  transverse  and  slightly  oblique  wrinkles  are  deve- 
loped on  the  anterior  and  the  posterior  faces  ; these  converge  upwards 
towards  the  orifices  of  the  tubes,  but  are  very  compact  at  the  lower 
part  where  they  begin  to  appear,  and  gradually  extend  over  the  whole 
of  the  uterus. 

There  forms  also  imperceptibly  on  the  two  faces  of  the  organ  an 
elongated  eminence  which  passes  through  its  whole  length,  and  to- 
ward which  the  wrinkles  on  each  side  converge  from  above  down- 
ward. These  wrinkles  enlarge  very  much.  They  render  all  the 
inner  face  of  the  uterus  very  uneven,  not  only  in  the  full-grown  fetus, 
but  also  during  the  early  period  of  life.  They  however  gradually  dis- 
appear in  the  body,  and  at  the  age  of  five  years  its  inner  face  is  en- 
tirely smooth. 

The  external  orifice  of  the  uterus  appears  at  first  as  a slightly  per- 
ceptible prominence  of  the  organ  in  the  vagina  ; but  this  prominence 
gradually  increases,  so  that  in  the  latter  periods  of  fetal  exist- 
ence, the  vaginal  portion  of  the  uterus  is  proportionally  much  larger 
than  subsequently.  At  seven  and  eight  months  less  than  in  the  full- 
grown  fetus,  and  during  the  first  months  after  birth,  all  this  portion  of 
the  organ  is  very  uneven,  and  also  on  its  external  face,  presents  longitu- 
dinal wrinkles,  terminated  by  sharp  uneven  edges,  which  are  deeply 
fissured,  the  grooves  of  which  often  occupy  all  the  vaginal  portion. 
This  prominence  afterwards  shortens,  becomes  smooth  externally, 
takes  the  form  of  a glove,  and  the  uterine  orifice  then  appears  as  a 
simple  and  smooth  transverse  fissure. 

. The  parietes  of  the  uterus  are  as  much  thinner  in  proportion  to  the 
'cavity,  the  younger  the  fetus  is.  At  first  they  are  equally  thick  in 
every  part  ; but  at  five  months  they  become  much  thicker  in  the  neck 
than  at  the  upper  part.  Gradually  between  the  age  of  five  and  six 
years,  the  thickness  again  becomes  uniform  in  every  part,  and  pre- 
serves its  character  till  puberty,  at  which  time  the  body  is  much  thicker 
than  the  neck. 

Thus  the  uterus  does  not  assume  till  very  late,  its  form  and  the  nor- 
mal thickness  of  its  parietes  ; but  it  acquires  ils  permanent  length 


442 


DESCRIPTIVE  ANATOMr. 


much  sooner,  at  least  in  great  part.  It  is  even  proportionally  longer 
at  first,  for  instance  in  the  full-grown  fetus,  than  subsequently. 

It  is  the  body  principally  which  grows  in  the  adult,  and  the  uterus 
then  assumes  a triangular  form.  In  females  advanced  in  age,  it  be- 
comes irregularly  rounded,  which  does  not  depend  on  previous  preg- 
nancies, since  the  same  changes  are  observed  in  old  unmarried  females. 
At  the  same  time  it  diminishes  in  those  females  who  have  lived  in 
celibacy. 

The  consistence  and  the  color  of  the  uterus  in  old  age,  resemble 
those  of  infancy.  At  these  two  periods  the  organ  is  hard  and  white, 
while  in  the  prime  of  life  it  is  soft  and  red. 

In  the  fetus  of  three  or  four  months,  the  uterus  is  situated  almost 
entirely  out  of  the  small  pelvis,  and  it  extends  much  beyond  in  the  full- 
grown  fetus.  After  the  age  of  fifteen  years,  it  is  entirely  situated  in 
the  pelvis,  at  the  base  of  which  it  is  found  in  old  females. 

In  the  fetus  it  is  almost  perpendicular,  but  its  direction  gradually 
changes,  so  that  its  greatest  diameter  is  directed  almost  exactly  from 
before  backward. 

§ 2497.  The  functions  of  the  uterus  as  well  as  its  form,  present  con- 
siderable periodical  differences. 

At  the  period  of  puberty,  when  the  female  has  the  power  of  concep- 
tion, there  is  every  month  a discharge  of  blood  and  serum  from  the 
genital  organs,  which  continues  some  days,  and  is  termed  menstruation 
( menstruatio , s.  menses ),  from  its  occurring  periodically.  This  discharge 
disappears  with  the  susceptibility  for  conception,  usually  between  the 
fortieth  and  the  fiftieth  year.  It  is  not  a character  belonging  exclu- 
sively to  women.(l)  This  discharge  proceeds  from  the  whole  inner 
face  of  the  uterus. 

The  discharge  usually  continues  some  days,  at  most  a week. 

The  quantity  of  blood  may  be  estimated  between  six  and  eight 
ounces. 

Its  color  is  dark,  from  which  character  alone  it  is  very  probably 
venous, (2)  which  is  not  the  general  opinion. 

This  conjecture  is  strengthened  by  chemical  analysis.  In  fact, 
Lavagna(3)  has  found  in  it  no  fibrin.  But  Saissy  and  Mayer(4)  have 
proved  that  the  venous  blood  contains  less  fibrin,  and  consequently  less 
azote  than  the  arterial  blood. 

The  uterus  enlarges  a little  during  menstruation  ; its  vessels  dilate 
and  project  like  villosities  on  its  inner  surface.  (5) 

Menstruation  essentially  consists  undoubtedly  in  an  increase  of 
the  vitality  of  the  genital  organs  of  the  female,  resembling  inflamma- 
tion, and  of  which  hemorrhage  is  the  crisis.  This  is  demonstrated  by 

(1)  Cuvier,  Annales  du  Muséum,  vol.  ix.  p.  118-130. — Kahleis,  Remarques  sur  la 
menstruation  ; in  the  Journ.  compl.  des  sc.  méd.,  veil.'  xviii.  p.  252. 

(2)  J.  F.  Csiander,  Diss.  de  fiuxu  menstruo  atque  uteri  prolapsu,  Gottingen, 
1808,  cap.  iii. 

(3)  In  Brugnatelli,  Giornale  difisica,  1817,  p.  397-416. 

(4)  Deutsches  Archiv  für  die  Physiologie,  vol.  iii.  p.  534. 

(5)  Osiander,  cap.  i-ii. 


Ol’  THE  GENITAL  SYSTEM. 


443 


the  irritation  in'  these  organs  before  the  period  of  menstruation,  the 
greater  propensity  of  the  female  at  that  time  for  coition,  and  the  greater 
facility  with  which  she  conceives. 

We  may  also  consider  it  as  an  attempt  to  form  a new  organism.  In 
fact,  the  changes  in  the  uterus  at  this  period,  resemble  those  observed 
in  it  after  conception.  On  the  other  hand,  according  to  the  observa- 
tions of  Denman,  Brandis,  and  Joerg,  the  menstrual  blood  is  not  unfre- 
quently  attended  with  membranous  productions,  similar  to  the  deci- 
duous membrane  which  is  developed  when  the  female  has  conceived. 

Finally,  menstruation  may  carry  off  from  the  body  generally,  and 
the  genital  organs  particularly,  probably  not  injurious  substances,  but 
at  least  superfluous  blood,  for  while  the  female  is  disposed  to  con- 
ceive, the  blood  always  collects  in  these  organs  from  one  menstruating 
period  to  another,  to  form  there  a new  organism,  and  during  pregnancy 
and  lactation  it  is  employed  in  other  formations. 

C.  TAGÏNA, 

§ 2498.  At  first  the  vagina  is  not  broader  than  the  uterus,  and  is 
entirely  smooth  like  it.  It  begins  to  be  uneven  at  about  the  same 
time.  First,  at  about  the  fifth  month  a longitudinal  elevation  appears 
on  each  anterior  and  posterior  face.  This  elevation  afterwards  presents 
very  many  large  transverse  folds  arranged  very  compactl}7.  These 
folds  are  united  by  others,  which  are  oblique,  and  are  distributed  on  the 
whole  circumference  of  the  vagina,  so  as  to  render  its  surface  much 
more  uneven  and  reticulated,  as  they  themselves  present  numerous 
fissures  and  folds.  This  is  the  appearance  of  the  vagina  at  seven  and 
eight  months.  But  the  folds  gradually  dimmish  ; they  are  less  evident 
in  the  full-grown  fetus  ; they  afterwards  gradually  disappear,  become 
less  prominent,  more  closely  united,  farther  from  each  other,  so  that  at 
the  period  of  puberty,  even  before  coition,  the  vagina  is  much  smoother, 
and  is  only  corrugated  at  its  lower  extremity  on  its  anterior  and  pos- 
terior faces,  in  the  first  more  than  in  the  second. 

At  first  the  vagina  is  always  proportionally  narrower  than  it  is  sub- 
sequently. It  is  undoubtedly  broadest  in  proportion,  about  the  seventh 
and  eighth  month. 

It  is  always  proportionally  longer  in  the  fetus  than  subsequently. 
It  is  always  more  than  two  inches  long  in  the  fetus  of  eight  months, 
and  in  the  child  at  birth,  while  in  the  adult  female  its  length  is  seldom 
more  than  four  inches.  This  arrangement  depends  at  least  in  part  on 
the  higher  situation  of  the  uterus,  but  not  entirely  on  this,  as  the 
vagina  is  not  narrower  in  the  same  proportion. 

D.  HYMEN. 

§ 2499.  The  vagina  is  much  narrower  at  its  lower  part  than  in 
other  places.  We  discover  no  trace  of  the  hymen  before  the  middle  of 
gestation.  At  this  time  it  begins  to  appear  on  each  side  in  the  form 


444 


DESCRIPTIVE  ANATOMY. 


of  a thin  and  narrow  prominence,  which  is  directed  from  behind  for- 
ward, so  that  a longitudinal  fissure  exists  in  the  centre.  This  promi- 
nence is  at  first  directed  downward,  and  is  equally  broad  in  every  part; 
but  it  gradually  becomes  broader  backward,  so  as  to  form  a semicircu- 
lar fold,  or  rather  a rounded  and  oblong  septum,  which  presents  an 
opening  at  its  anterior  extremity.  The  hymen  preserves  this  form 
until  it  is  destroyed.  The  inequalities  of  the  vagina  are  also  con- 
tinuous in  the  fetus,  on  it,  and  on  the  orifice  of  the  urethra,  from 
whence  they  descend  on  the  clitoris,  and  the  inner  face  of  the  internal 
labia. 

III.  CLITORIS. 

§ 2500.  When  the  sexual  organs  are  once  developed,  the  clitoris  is 
proportionally  very  large,  and  the  more  so  the  younger  the  fetus  is. 

At  the  commencement  of  the  third  month,  when  the  latter  is  at  most 
but  two  inches  long,  its  length  is  about  one  line,  and  it  is  half  a line 
thick.  In  fact,  it  soon  loses  these  large  proportions,  but  it  remains 
considerable  during  the  whole  of  gestation,  so  that  a slight,  examina- 
tion might  easily  deceive  in  regard  to  the  sex  of  the  child,  which  is 
more  probable,  because  the  scrotum  is  then  very  small,  and  the  testicles 
are  situated  in  the  abdomen  ; but  the  clitoris  is  always  turned  forward 
and  downward,  and  never  looks  toward  the  umbilicus.(l) 

This  organ  presents  a deep  fissure  on  the  whole  of  its  lower  face. 
At  three  months  we  distinguish  a longitudinal  eminence  on  the  centre 
of  this  lower  face. 

The  glans  is  not  entirely  exposed  until  the  fourth  month  ; it  forms  a 
rounded  prominence,  and  is  distinctly  separated  from  the  rest  of  the 
clitoris.  When  this  period  has  elapsed,  the  prepuce  grows  rapidly, 
and  entirely  envelops  it.  The  posterior  part  of  the  clitoris  is  composed 
of  the  internal  labia  and  the  prepuce  ; the  internal  labia  are  then  very 
much  developed  during  the  early  periods  ;(2)  we  cannot  distinguish 
them  from  the  prepuce,  with  which  they  are  directly  continuous.  As 
the  prepuce  forms  and  extends  on  the  glans,  a line  of  demarkation 
gradually  forms  between  it  and  the  internal  labia,  the  edge  of  which 
was  at  first  straight,  becomes  rounded  ; at  the  same  time  they  evi- 
dently divide  at  their  anterior  part,  and  on  each  side,  into  two  branches, 
the  one  small  and  internal,  which  goes  to  the  glans,  the  other  external, 
going  to  the  prepuce.  Previously  there  was  no  trace  of  these  two 
branches. 

Thus  the  clitoris  and  the  labia  form  originally  but  one  mass. 

(1)  Walter,  Physiologie , vol.  ii.  p.  328. 

(2)  According-  to  Osiander  ( Abhandlungen  über  die  Scheidenldappe ; in  the 
Denkwürdigkeiten  Jur  die  Heilkunde,  vol.  ii.  p.  46),  the  nymphæ  are  very  imper- 
fect, and  hardly  perceptible  at  three  and  four  months  ; observation  disproves  this 
assertion.  The  fact  is,  that  the  internal  labia  are  not  so  large  in  proportion  to  the 
very  large  clitoris,  as  they  are  afterward,  but  they  are  very  large  in  respect  to  the 
genital  organs  and  the  whole  body,  so  that  they  cannot  be  mistaken  for  what  they 
really  are  not. 


OF  THE  GENITAL  SYSTEM. 


445 


IV.  EXTERNAL  LABIA. 

§ 2501.  The  external  labia  are  at  first,  at  three  months,  small, 
rounded,  semicircular  sacs,  convex  outward,  much  thicker  anteriorly 
than  posteriorly,  and  nearer  each  other  at  their  anterior  than  at  their 
posterior  extremities,  and  separated  forward  by  the  large  clitoris,  which 
projects  much  beyond  them.  They  gradually  enlarge,  approach  each 
other,  as  the  clitoris  does  not  increase  in  the  same  proportion,  become 
more  elevated  and  thinner,  and  thus  their  edge  becomes  sharper. 
They  never,  however,  cover  the  clitoris  and  the  nymphæ  entirely, 
during  the  early  periods  of  existence  ; first,  because  these  parts  are  al- 
ways considerably  large;  second,  because  they  themselves  are  but 
slightly  developed. 

II.  GENITAL  ORGANS  IN  THE  MALE. 

§ 2502.  The  genital  organs  in  the  male  during  their  development, 
pass  through  several  periods,  which  are  very  important  in  a physiolo- 
gical, pathological,  and  surgical  point  of  view.  The  differences  they 
present,  relate  to  their  situation,  form,  and  size. 

I.  TESTICLES. 

§ 2503.  The  testicles(l)  deserve  to  be  first  considered,  as  they  are 
the  most  important  parts,  and  appear  first. 

They  form  not  in  the  scrotum,  but  in  the  abdomen,  and  particularly 
in  the  peritoneal  cavity,  and  has  the  same  relation  to  it  as  have  all  the 
other  organs  enveloped  by  this  membrane. 

About  the  middle  of  the  third  month  their  upper  extremity  still 
touches  the  lower  extremities  of  the  kidneys.  At  this  time  they  are 
situated  obliquely  from  above  downward,  and  from  without  inward, 

(1)  Haller,  De  lierniis  congenilis,  programma  ad  dissertationem  tSteding,  Got- 
tingen, 1749.' — Pott,  Oïl  ruptures,  1756,  p.  13.— Camper,  in  Verhandetingen  vanhet 
Harlcmsche  genootschap,  1761,  vol.  vi.  part  i. — J.  Hunter  and  G.  Hunter,  Medical 
commentaries , London,  1762,  p.  1.  p.  75. — Id.,  in  Observations  on  certain  parts  of  the 
animal  economy,  vol.  i. — Arnaud,,  in  Mémoires  de  chirurgie,  vol.  i.  no.  i.  London, 
1768. — Lobstein,  De  herniâ  congenita,  in  qua  intestinum  in  contactu  testis  est, 
Strasburg,  1771.— J.  F.  Meckel,  De  morbo  hernioso  congenito  singulari,  Berlin, 
1772. — Girardi,  in  Santorini,  Septem,  tab., . Parma,  1775,  p.  184-202. — J.  B.  Palletta, 
Nova  gubernaculi  testis  Hunteriani  et  tunicœ  vaginalis  anatomica  descriptio,  Milan, 
1777. — H.  A.  Wrisberg,  Observationes  anatomicoe  de  testiculorum  ex  abdomine  in 
scrotum  descensu,  Gottingen,  1779. — Vicq-d’Azyr,  in  Mém.  de  Paris,  1780,  p.  494- 
507. — -J.  Brugnone,  De  testium  in  fcetu  positu,  dé  eorum  in  scrotum  descensu,  de 
tunicarum  quibus  hic  continentur,  numéro  et  origine,  Turin,  1785. — Tumiati,  loc. 
cil.,  p.  541. — J.  F.  Lobstein,  Recherches  et  observations  anatomico-physiologiques 
sur  la  position  des  testicules  dans  le  bas-ventre  du  fœtus  et  leur  descente  dans  le  scro- 
tum ; in  Schweighæuser,  Archives  de  V art  des  accouchemens,  Strasburg,  1801,  vol. 
i.  p.  269. — B.  G.  Seiler,  Observationes  nonnullœ  de  testiculorum  ex  abdomine  in  scro- 
tum descensu  et  partium  genitalium  anomaliis,  Leipsic,  1817. 

Vol.  III.  57 


446 


DESCRIPTIVE  ANATOMY. 


fill  the  space  between  the  kidney  and  the  bladder,  and  consequently 
occupy  all  the  inner  face  of  the  ossa  ilia. 

They  are  very  large,  since  in  the  fetus  of  this  age,  which  is  scarcely 
more  than  two  inches  long,  they  are  two  lines  in  length  and  one  line 
thick.  They  are  rounded  and  oblong,  convex  anteriorly  and  concave 
posteriorly,  and  rest  on  a very  broad  fold  of  the  peritoneum,  which  first 
covers  the  epidydimis,  then  goes  on  the  posterior  and  concave  face  of 
the  testicle,  leaving  between  them  a great  space,  arises  from  the  pos- 
terior face  of  this  gland,  but  is  by  no  means  as  high  as  that,  and  is 
very  similar  to  the  epiploon.  They  adhere  to  this  fold  so  slightly,  that 
their  situation  is  easily  changed,  and  particularly  carried  outward  or 
inward.  The  epidydimis  rises  no  higher  than  the  testicle,  descends  at 
its  side  from  before  backward,  and  a little  from  within  outward,  and  is 
continuous  at  its'lower  extremity  with  the  vas  deferens,  which  descends 
into  the  small  pelvis  behind  the  peritoneum.  At  the  place  where  this 
continuation  occurs,  the  whole  mass,  but  the  epidydimis  and  vas  de- 
ferens particularly,  rest  directly  on  a short,  very  fine,  rounded  cord, 
which  arises  from  a depression  of  the  lower  wall  of  the  peritoneum,  at 
about-the  centre  of  the  crural  arch,  which  is  also  covered  by  the  peri- 
toneal membrane,  but  less  loosely  than  the  testicle,  because  the  fold  is 
shorter  in  the  point  which  corresponds  to  it.  This  cord  is  infinitely 
thinner  than  the  testicle  and  the  epidydimis. 

It  is  the  sheath  (vagina)  of  Haller,  the  gubtrnaculum  of  Hunter, 
the  cylinder  of  Camper,  the  basis  of  Gerardi. 

After  this  period  the  proportionally  large  size  of  the  testicles  rapidly 
diminishes. 

At  four  months,  when  the  fetus  is  four  inches  long  from  the  vertex 
to  the  coccyx,  their  length  is  scarcely  two  lines  and  a half,  and  their 
thickness  at  most  but  one  line.  The  epidydimis  is  then  larger  in  pro- 
portion to  the  testicle,  than  before  or  afterward.  The  testicles  are  situ- 
ated a little  lower,  but  very  little  however,  but  are  more  remote  from 
the  kidneys,  being  at  least  four  lines  from  them,  because  the  ossa  ilia 
are  much  larger.  The  vas  deferens  is  then  reflected  a little  from  below 
upward  on  leaving  the  lower  extremity  of  the  epidydimis,  so  that  it  de- 
scribes an  arch  before  descending  into  the  pelvis.  The  gubernaculum 
is  much  larger,  and  it  arises  from  the  region  of  the  inguinal  ring,  al- 
though the  peritoneum  is  not  perforated  in  this  place  ; but  is  only  re- 
flected on  itself  from  below  upward,  and  envelops  a mucous  mass  to 
which  we  must  attribute  the  thickness  and  the  more  round  form  of 
the  gubernaculum. 

At  five  months,  the  testicles  are  not  longer  than  in  the  preceding 
month,  but  they  are  about  half  a line  thicker,  so  that  they  appear  a 
little  rounder  than  they  were  then.  They  have  not  descended  lower, 
or  at  least  but  very  little,  and  they  are  still  more  than  a line  distant 
from  the  lower  wall  of  the  peritoneum.  The  gubernaculum,  which  is 
then  evidently  triangular  and  the  summit  of  which  is  much  thinner 
than  the  inguinal  ring  and  goes  downward,  while  its  base  looks  up- 
ward, ascends  obliquely  from  within  outward.  It  begins  a little  below 


OF  THE  GENITAL  SYSTEM. 


447 


the  inguinal  ring,  at  the  upper  part  of  the  scrotum,  by  some  distinct 
fibres,  passes  through  the  ring,  then  receives  some  fibres  from  the  ob- 
liquus  internus  and  transversalis  abdominis  muscles,  behind  which  it 
passes,  then  ascends  on  the  iliacus  muscle,  and  rises  directly  to  the 
lower  extremity  of  the  epidydimis.  At  its  lower  part,  between  the  in- 
guinal ring  and  the  place  where  it  appears  in  the  abdominal  cavity, 
we  discover  before  it  a prolongation  of  the  peritoneum  {processus  peri- 
tonei) which  terminates  in  the  ring  in  a cul-de-sac.  This  prolongation 
also  descends  obliquely  from  without  inward.  Its  upper  orifice  is  much 
broader  than  the  lower,  and  than  the  gubernacuium  which  passes 
through  it.  This  last  is  filled  with  a soft  and  gelatinous  mass  ; it  how- 
ever contains  no  cavity.  The  epidydimis  is  evidently  tortuous  at  its 
lower  part,  and  the  vas  deferens  is  slightly  so  at  its  origin. 

At  six  months  the  testicles  are  still  situated  in  the  same  place.  At 
this  time  they  are  only  four  lines  long,  and  one  and  a half  thick,  so 
that  they  are  proportionally  oblong,  and  almost  straight.  The  epidy- 
dimis rises  a little  above  the  surface  of  the  glans,  and  like  the  vas  de- 
ferens, it  is  more  distinctly  curved  than  in  the  preceding  month.  The 
same  is  true  of  the  gubernacuium  and  the  prolongation  of  the  perito- 
neum. Sometimes  we  may  pass  air  into  the  lower  part  of  the  guber- 
nacuium, and  it  is  sufficient  in  certain  cases  to  cut  it  across  to  perceive 
that  it  is  hollow. 

Thus,  there  has  hitherto  existed  a canal,  terminated  in  a cul-de-sac, 
a prolongation  of  the  peritoneum,  which  descends  from  about  the 
centre  of  the  lower  tendon  of  the  obliquus  abdominis  externus  muscle, 
between  this  muscle  and  the  lower  edge  of  the  two  broad  internal  ab- 
dominal muscles,  and  behind  which  proceeds  a prolongation  of  mucous 
tissue,  which  is  generally  solid,  and  to  which  are  added  some  fleshy 
fibres  from  the  two  broad  internal  abdominal  muscles.  But  the  testicle 
is  still  loose  in  the  cavity  of  the  peritoneum,  where  it  rests  on  the  upper 
extremity  of  the  gubernacuium. 

At  seven  months  we  generally  find  it  directly  on  the  upper  extre- 
mity of  the  canal,  or  more  or  less  within  it,  so  that  frequently  it  does 
not  project  at  all  beyond -it,  or  only  in  a very  small  part  of  its  upper 
extremity.  It  is  usually  situated  behind  the  lower  edge  of  the  obli- 
quus abdominis  extemus  muscle.  The  prolongation  of  the  peritoneum 
then  extends  downward,  to  just  above  the  inguinal  ring.  It  seems 
composed  of  two  lajrnrs,  the  internal  of  which  is  thinner,  and  is  con- 
tinuous with  the  peritoneum,  while  the  external  is  a mucous  tissue, 
and  is  continuous  with  the  sheath  of  the  obliquus  abdominis  externus 
muscle,  in  which  are  distributed  the  fleshy  fibres  coming  from  the  ob- 
liquus internus  abdominis  and  the  transversalis  muscles.  The  lower 
part  of  the  prolongation  of  the  peritoneum  is  filled  above  by  the  lower 
extremity  of  the  epidydimis,  and  by  the  commencement  of  the  vas  de- 
ferens ; these  rest  on  a small  mass  of  mucous  substance,  which 
rises  from  the  lower  extremity  of  the  prolongation  of  the  peritoneum, 
and  they  are  united  with  it  posteriorly  by  a fold,  which  is  detached 
from  the  posterior  wall  of  this  prolongation. 


448 


DESCRIPTIVE  ANATOMY. 


At  eight  months,  the  testicle  itself  usually  passes  through  the  ingui- 
nal ring,  and  gradually,  until  the  end  of  the  ninth  month,  arrives  at  the 
bottom  of  the  sacrum,  so  that  its  situation  is  normal  about  the  period 
of  birth.  The  prolongation  of  the  peritoneum  is  then  considerably 
elongated  ; it  is  open  its  whole  extent,  excepting  only  its  lower  extre- 
mity, which  terminates  in  a cul-de-sac,  and  it  communicates  freely  by 
its  upper  with  the  proper  peritoneal  cavity. 

After  the  testicle  has  descended  entirely  to  the  bottom  of  the  peri- 
toneal’prolongation  and  of  the  scrotum,  its  cavity  still  continues  to  com- 
municate with  that  of  the  peritoneum  for  a greater  or  less  length  of 
time,  but  not  more  than  a few  weeks  when  the  development  is  perfectly 
normal.  But  the  canal  of  union  gradually  contracts  at  its  centre,  a 
little  nearer  the  top  than  the  bottom,  so  that  usually  that  portion  of 
the  prolongation  of  the  peritoneum  which  surrounds  the  testicle,  begins 
to  be  obliterated  near  the  inguinal  ring.  The  upper  portion  of  the 
canal  from  the  inguinal  ring  to  the  centre  of  the  crural  arch,  or  to 
the  place  where  the  vas  deferens  joins  the  spermatic  vessels,  remains 
open  for  a considerable  time  ; but  when  the  child  is  regularly  deve- 
loped, it  is  also  obliterated  during  the  first  months  after  birth,  so  that 
it  is  finally  only  indicated  by  a slight  depression,  which  by  no  means 
always  exists. 

The  central  portion  of  the  canal  of  communication  also  is  perfectly 
obliterated  as  high  as  the  upper  extremity  of  the  testicle,  and  entirely 
disappears  in  most  cases.  At  least  we  have  rarely  been  able  to  see 
any  traces  of  it,  although  we  have  made  the  most  careful  examina- 
tions on  this  subject.  We  cannot  then  agree  with  Brugnone  and 
Scarpa,  that  we  always  find  in  the  adult  a special  cord,  composed  of 
cellular  tissue,  termed  by  them  the  bridle  {habenula),  which  they  con- 
sider as  the  remains  of  a canal  of  communication,  and  the  cavity  of 
which  they  assert  can  always  be  demonstrated  by  maceration. 

Thus  the  canal  of  union  is  first  obliterated,  and  then  disappears. 
Adhesion  in  it  results  from  its  serous  nature,  and  like  its  disappearance, 
it  is  perhaps  favored  by  the  pressure  of  the  testicle  upon  it. 

§ 2504.  Farther,  these  changes  in  the  situation  of  the  testicles  do 
not  occur  at  the  same  period,  and  uniformly  on  the  two  sides  ; one 
of  the  two  organs  usually  comes  into  the  scrotum  long  before  the 
other. 

The  anomalies  in  the  progress  of  this  phenomenon  are  as  follow  : 

1st.  The  early  descent  of  the  testicles.  This  case  is  rare  : Wris- 
berg  has  found  the  testicles  in  the  scrotum  at  four  and  five  months, 
and  has  also  remarked  that  the  canal  of  communication  was  then 
obliterated.(l) 

2d.  A suspension  of  development,  from  whence  several  periods  are 
retarded,  or  even  never  supervene.  This  case  is  much  more  common 
than  the  preceding.  The  greatest  anomaly  is  where  one  testicle  or 


(1)  Loder,  Journal , vol.  i.,  p.‘175. 


W THE  GENITAL  SYSTEM. 


449 


both  remain  in  the  abdomen  or  in  the  inguinal  region,  from  whence 
we  may  think  one  or  both  of  these  organs  are  deficient. 

In  this  case  the  testicles  are  arranged  in  regard  to  their  envelops 
precisely  in  the  same  manner  as  in  the  fetus,  as  they  are  entirely  ex- 
posed, and  are  provided  with  a gubernaculum.  The  least  anomaly 
is  where  the  peritoneal  prolongation  is  imperfectly  obliterated.  When 
this  last  anomaly  exists  in  the  greatest  degree,  the  canal  remains  en- 
tirely open,  so  that  the  testicle  is  inclosed  in  the  same  cavity  as  the 
other  abdominal  viscera,  although  its  position  is  otherwise  changed. 
When  the  anomaly  is  less,  sometimes  and  most  frequently,  only  the 
upper  part  of  the  peritoneum  is  open,  which  extends  between  the  in- 
guinal ring  and  the  obliquus  abdominis  internus  muscle  ; sometimes 
and  more  rarely  the  lower  part  of  the  prolongation  does  not  adhere,  so 
that  not  only  the  layer  which  surrounds  the  testicle,  and  which  be- 
comes the  external  layer  of  its  proper  vaginal  tunic,  forms  an  oblong 
and  rounded  cavity,  but  also  we  see  arise  from  the  upper  extremity  of 
this  sac  a canal  varying  in  length,  which  marks  the  old  canal  of  com- 
munication ; sometimes  finally  and  more  unfrequently,  the  obliteration 
occurs  regularly  at  the  two  extremities  of  the  canal  of  union,  but  the 
central  part  of  this  latter  continues  in  a greater  or  less  extent. 

We  shall  mention  hereafter  the  diseases  produced  by  these  ano- 
malies. 

§ 2505.  The  testicle  differs  considerably  both  in  respect  to  situation 
and  its  envelops,  whether  it  is  found  in  the  abdominal  cavity  or  in  that 
of  the  scrotum. 

While  it  is  situated  in  the  abdomen,  it  is  surrounded  only  by  the 
albugineous  tunic  and  the  portion  of  the  peritoneum  which  passes  on 
this  membrane. 

The  fold  of  the  peritoneum,  which  is  attached  to  the  latter,  is  conti- 
nuous with  the  posterior  wall  of  the  peritoneum,  and  at  this  period  the 
testicle,  like  the  other  abdominal  viscera,  is  not  inclosed  in  a proper 
capsule,  with  which  this  serous  fold  is  continuous,  as  are  the  lungs  or 
the  heart. 

The  other  envelops  which  cover  it  in  the  scrotum  are  developed  at 
the  expense  of  the  gubernaculum,  and  the  prolongation  of  the  perito- 
neum. The  peritoneum  becomes  the  external  and  loose  layer  of  the 
proper  vaginal  tunic  of  the  testicle,  with  which,  when  the  testicle  has 
descended,  the  internal  layer  is  continuous,  precisely  in  the  same  man- 
ner as  it  was  previously  connected  with  the  external  wall  of  the  peri- 
toneum. 

The  common  vaginal  tunic  of  the  testicle  and  the  spermatic  cord  is 
formed  from  the  cellular  tissue  within  the  gubernaculum. 

At  this  period  also  the  fibres  coming  from  the  two  internal  muscles 
of  the  abdomen,  which  were  at  first  ascending,  go  outward,  and  form 
the  cremaster  muscle.  The  cellular  tunic  or  the  dartos  already  ex- 
isted in  the  scrotum,  and  the  testicle  entered  it  on  descending. 

These  changes  depend  principally  on  the  fact  that  the  gubernacu- 
lum gradually  turns,  so  that  its  internal  face  becomes  external,  and  its 


450 


DESCRIPTIVE  ANATOMY. 


upper  extremity  becomes  the  lower  ; hence  the  epidydimis  which  is 
attached  to  it,  and  with  it  the  testicle,  are  necessarily  drawn  from 
above  downward.  The  prolongation  of  the  peritoneum  also  emerges 
in  the  same  manner  outward,  and  independent  of  this  inversion,  since 
it  already  exists  before  the  testicle  descends,  and  it  supervenes  also  in 
hernias  which  are  caused  simply  by  the  spontaneous  prolapsus  of  the 
peritoneum,  without  any  other  mechanical  change. 

The  descent  of  the  testicle  is  generally  explained  entirely  in  a me- 
chanical manner,  and  attributed  to  the  compression  produced  by  the 
motions  of  respiration  upon  the  abdominal  viscera,(l)  or  to  the  weight 
of  the  testicle, (2)  or  to  the  greater  flow  of  blood  into  its  vessels, (3)  or 
finally  to  the  contraction  and  inversion  or  to  the  reversion  of  the  guber- 
naculum.(4) 

The  first  opinion  is  not  correct,  since  when  the  formation  is  normal 
the  testicles  usually  descend  in  the  scrotum  long  before  birth,  and  they 
are  often  found  in  the  abdominal  cavity  long  after  parturition,  when 
the  formation  is  abnormal.  The  second  is  refuted  by  the  habitual 
situation  of  the  fetus,  as  the  testicle  would  ascend  against  its  specific 
gravity.  The  third  is  inadmissible,  because  if  true  the  testicles  should 
be  situated  as  much  lower  the  younger  the  fetus  is,  since  then  they 
are  proportionally  the  largest. 

The  contraction  of  the  gubernaculum  doubtless  does  not  cause  the 
gliding  of  the  testicle  to  the  inguinal  ring  ; but  it  does  not  contribute 
to  its  farther  progress  in  the  scrotum,  for  instead  of  favoring  its  motion 
in  this  direction  it  would  rather  contribute  to  raise  it.  "We  cannot, 
however,  deny  that  it  assists  very  much  to  the  displacement  of  the 
organ,  and  this  is  proved  positively  by  the  great  development  of  the 
muscular  fibres  of  the  gubernaculum  in  those  animals  where  the  tes- 
ticles possess  alternate  motions,  whence  they  enter  and  leave  the 
cavity  of  the  abdomen  alternately. 

If  sometimes  the  testicles  do  not  descend,  although  the  gubernacu- 
lum exists,  we  must  not  conclude  that  this  latter  takes  no  part  in  the 
phenomenon,  since  other  circumstances  may  prevent  its  action,  or  at 
least  may  produce  the  effects  it  generally  causes.  Farther,  its  con- 
traction is  only  one  mode  of  causing  the  displacement  of  the  testicle, 
and  the  cause  of  this  displacement  is  unknown  to  us. 

§ 2506.  When  man  has  passed  the  period  of  his  virility,  the  tes- 
ticles diminish  a little,  at  least  frequently  ; but  they  rarely  waste  as 
much  as  the  ovaries,  and  the  power' of  impregnation  continues  longer 
in  the  male  than  that  of  conception  in  the  female. 

The  scrotum  gradually  relaxes  more  or  less,  so  that  the  testicles 
descend  lower. 

(1)  Haller. 

(2)  Haller,  Pott. 

(3)  Haller,  Tumiati. 

(4)  Paletta,  Vicq-d’Azyr,  Bruguone. 


OF  THE  GENITAL  SYSTEM. 


451 


§ 2507.  The  secretion  of  semen  commences  about  the  same  time 
that  menstruation  does,  but  it  usually  continues  a little  longer. 

II.  PENIS. 

§ 2508.  About  the  middle  of  the  third  month  the  glans  is  not  yet 
covered  by  the  prepuce,  and  a deep  groove  separates  it  posteriorly 
from  the  proper  penis,  which  is  larger  than  it. 

Its  anterior  extremity  is  imperforate  ; we  only  perceive  a whitish 
spot  at  the  place  where  the  urethra  afterwards  opens.  But  we  always 
observe  at  this  period  a longitudinal  fissure,  which  sometimes  exists 
posteriorly  on  the  small  portion  of  the  lower  face  of  the  glans  and 
which  constantly  occupies  the  anterior  extremity  of  the  lower  face  of 
the  penis  situated  directly  next  to  it. 

Thus  the  urethra  does  not  extend  as  far  forward  as  when  the  de- 
velopment is  completed,  and  farther  its  anterior  part  presents  a fissure 
below.  This  fissure,  however,  by  no  means  extends  to  the  posterior 
extremity  of  the  penis. 

The  scrotum  is  very  small,  is  separated  very  distinctly  from  the 
penis  forward,  and  is  entirely  closed. 

At  four  months,  the  appearance  of  the  scrotum  is  not  changed,  but 
the  form  of  the  penis  is  altered.  The  glans  is  a little  larger  propor- 
tionally, is  covered  by  the  prepuce  at  its  posterior  and  inferior  part  so 
that  only  the  lower  part  of  its  anterior  side  is  exposed,  and  we  remark 
at  the  lower  part  of  its  anterior  surface  a longitudinal  fissure,  which  is 
the  opening  of  the  urethra. 

Next  comes  a state  directly  opposite,  which  continues  during  the 
whole  of  gestation.  The  prepuce  is  very  much  enlarged,  covers  the 
whole  glans,  and  presents  only  a very  narrow  opening  ; it  is  adapted 
so  intimately  to  the  surface  of  this  part  that  it  cannot  be  drawn  back- 
ward. 

Thus  in  the  normal  state  there  is  paraphymosis  during  the  early 
periods  of  fetal  existence,  and  phymosis  during  those  that  succeed. 


III.  MAMMÆ. 

§ 2509.  The  mammæ  are  already  apparent  at  the  third  month  of 
pregnancy,  at  which  period  the  nipple  is  scarcely  perceptible,  but  pre- 
sents a very'  broad  opening.  It  is  worthy  of  remark  that  they  gene- 
rally contain  during  the  latter  period  of  gestation,  and  in  the  fetus  at 
birth,  a lactescent  liquid,  of  which  there  is  often  a considerable  quan- 
tity. Until  the  period  of  puberty  they  present  no  marked  differences 
in  the  two  sexes  ; but  at  this  time  they  enlarge  more  or  less  in  the 
female. 


452 


DESCRIPTIVE  ANATOMY. 


They  are  more  or  less  hard  and  solid.  As  age  advances  they  di- 
minish, which  occurs  sooner  when  their  action  has  been  exhausted  by 
frequent  lactations.  Even  where  their  mass  does  not  seem  dimi- 
nished, and  they  are  even  enlarged,  the  substance  of  the  gland  is, 
however,  replaced  by  fat. 


ARTICLE  THIRD. 

DIFFERENCES  IN  THE  GENITAL  ORGANS  PRESENTED  BY  DIF- 
FERENT RACES. 

§ 2510.  Beside  the  differences  depending  on  the  sexes  and  the  pe- 
riods of  life,  the  genital  organs  present  others  which  relate  to  the  races 
of  the  human  species. 

The  most  remarkable  are  those  in  the  external  genital  organs  of  the 
female  and  the  mammæ. 

The  internal  labia  are  very  long  in  certain  Ethiopian  races,  among 
others  that  of  the  Boschismans,  as  we  have  already  mentioned. 
This  is  the  origin  of  the  apron  of  the  Hottentots,  which  the  recent 
observations  of  Somerville  and  Cuvier  have  demonstrated  not  to  be  a 
new  organ. 

The  mammæ  are  also  very  much  developed  and  very  long  in  the 
Hottentots,  who  can  throw  them  over  their  shoulders. 

We  have  already  mentioned  the  great  size  of  the  penis  in  ne- 
groes. 


ARTICLE  FOURTH. 

COMPARISON  OF  THE  MALE  AND  FEMALE  GENITAL  ORGANS. 

§ 2511.  We  have  already  mentioned  several  times  that  the  genital 
organs  of  the  two  sexes  are  formed  primitively  in  the  same  model,  and 
that  they  should  be  considered  only  as  modifications  of  the  same  fun- 
damental type. 

In  fact  it  is  easy  to  demonstrate  that  all  the  parts  which  unite  to 
form  this  system  exist  equally  in  both  sexes,  and  differ  only  in  size, 
situation,  and  structure.  • The  analogy  appears  much  greater  the 
younger  the  fetus  is,  and  that  it  is  founded  on  the  nature  of  things  is 
proved  by  the  fact  that  they  are  originally  of  the  same  sex. 


OF  THE  GENITAL  SYSTEM, 


453 


The  testicles  Correspond  perfectly  to  the  ovaries  in  form  and  func- 
tions, the  vessels  and  nerves  they  receive,  and  even,  at  first,  in  situa- 
tion. 

The  Fallopian  tubes  are  evidently  analogous  to  the  vasa  deferentia. 
We  however  have  reason  to  think  they  originally  communicate  with 
the  ovaries  by  straight  canals,  and  by  a kind  of  epidydimis  similar  to 
that  which  exists  in  the  male  between  the  vas  deferens  and  the  tes- 
ticle. 

The  seminal  vesicles  and  the  prostate  gland  undoubtedly  corres- 
pond to  the  uterus  in  respect  to  situation  and  connection,  with  the 
vasa  deferentia,  and  the  Fallopian  tubes  ; the  uterus  however  is  larger 
and  more  completely  developed,  and  the  orifices  of  the  seminal  canals 
are  more  remote  from  each  other. 

The  penis  and  clitoris  are  similar  in  essential  respects  as  to  situation 
and  structure.  They  differ  only  in  their  respective  size,  and  because 
the  urethra  does  not  extend  under  the  clitoris.  This  difference  how- 
ever disappears,  when  we  consider  the  imperfect  development  of  the 
clitoris  is  compensated  by  that  of  the  vagina  or  nymphæ,  which  must 
consequently  be  regarded  as  the  penis  and  urethra  of  the  male,  the 
two  lateral  halves  of  which  are  separated,  and  which  are  turned  in- 
ward instead  of  outward. 

In  this  respect  also  the  analogy  is  greater  in  the  early  periods,  since 
then  the  urethra  does  not  extend  to  the  anterior  extremity  of  the  penis. 

We  explain  in  the  same  manner  the  difference  between  the  bulbo- 
cavernosi  and  the  constrictor  vaginæ  muscles.  These  two  muscles 
correspond  ; the  two  halves  of  the  second,  however,  are  united  only 
on  the  median  line. 

The  external  labia  represent  the  two  halves  of  the  scrotum,  which 
are  separated. 

The  mammæ  differ  only  in  size,  and  this  difference  is  almost  nothing 
before  the  period  of  puberty. 

Thus  the  analogy  of  the  genital  organs  of  the  female  is  found  in 
the  other  sex.  The  history  of  hermaphrodites  will  demonstrate  that 
the  deviations  of  formation  contribute  still  more  to  efface  the  differ- 
ences between  the  two  series  of  organs,  and  these  anomalies 
produce  between  them  so  great  a resemblance,  that  it  is  often  very 
difficult  to  determine  to  what  sex  the  individual  really  belongs. 


VOL.  Ill 


58 


464 


DESCRIPTIVE  ANATOMY 


ARTICLE  FIFTH. 

GENITAL  ORGANS  IN  THE  ABNORMAL  STATE.(l) 

3.  GENERAL  ANOMALIES 

§ 2512.  The  genital  organs  present  some  anomalies  common  to  the 
two  sexes,  and  others  peculiar  to  one  only,  a remark  which  applies  also 
to  deviations  of  formation  and  alterations  of  texture.  In  this  respect 
we  must  remark,  that  the  corresponding  sections  of  the  genital  organs 
usually  participate  in  the  same  anomalies,  or  at  least  present  those 
which  are  very  analogous. 

We  observe  in  both  sexes  : 

1st.  Suspensions  of  development  and  developments  continuing  after 
the  type  of  the  fetus.  Such  are  : 

a.  The  entire  or  partial  absence  of  the  genital  organs.  The  first 
anomaly  causes  the  total  absence  of  sex,  although  the  rest  of  the  body 
sometimes  indicates  clearly  to  what  sex  the  individual  would  have  be- 
longed if  the  genital  organs  had  been  developed. 

b.  Abnormal  smallness. 

c.  The  abnormal  continuance  of  a primitive  formation. 

These  anomalies  are  not  rare. 

2d.  Plurality,  which  is  much  less  common. 

3d.  The  too  early  development,  although  more  common"  than  the 
preceding  anomaly,  is  however  a rare  phenomenon. 

(I)  Consult,  1st.  On  the  diseases  of  the  genital  organs  generally  : Vercelloni,  De 
pudendorum  morbis,  Leyden,  1725. — 2d.  On  those  of  the  organs  of  the  female  in  par- 
ticular : J.  G.  Walter,  lieber  die  Geburtstlieile  des  weiblichen  Geschlechts , Berlin, 
1776. — Justi,  Diss.  cxhibens  observationum  sericm  circa  genitalia  muliebria,  Mar- 
burg, 1798. — Thamm,  Diss.  de  genitalium  sexus  sequioris  varietatibus , Halle,  1799. 
— 3d.  On  those  of  the  external  genital  organs  of  the  female  : Louis,  De  partium  ex- 
ternarum generationi  inservientium  in  mulicribus  naturali , viiiosâ  et  morbosa  dis- 
positions, Baris,  1764. — 4th.  On  those  of  the  ovaries  ; Kruger,  PatholOgia  ovariorum 
muliebrium,  Gottingen,  1782. — Motz,  De  structura,  usu  et  morbis  ovariorum,  Gies- 
sen, 1789.— 5th.  On  those  of  the  Fallopian  tubes  : Leonhardi,  Quœdam  de  tubarüm 
uterinarum  morbis,  Wittemberg,  1808. — 6th.  On  those  of  the  matrix  and  of  the  va- 
gina : A.  Vater,  De  morbis  uteri,  Wittemberg,  1709. — Haller,  De  morbis  uteri,  Got- 
tingen, 1753. — Schwarz,  De  uteri  degeneraiione , Jena,  1792. — Clarke,  Diseases  of  fe- 
males, London,  1814. — 7th.  On  the  anomalies  of  the  hymen:  G.  Tolberg,  De  varie- 
tate  hymenum,  Halle,  1791. — Osiander,  loc.  cit. — 8th.  On  the  diseases  of  the  genital 
organs  of  the  male  in  general:  G.  Wadd,  Cases  of  diseased  bladder  and  testicle , 
London,  1815. — 9th.  On  those  of  the  testicle  : Henrel,  Diss . de  morbis  scroti,  Stras- 
burg, 1723. — J.  Warner,  Account  of  the  testicles  and  the  diseases  to  which  they  are 
liable,  London,  1774.-10.  On  those  of  the  prostate  gland  : E.  Home,  Observations  prati- 
ques et  pathologiques  sur  le  traitement  des  maladies  de  la  glande  prostate,  Paris, 
1820. — llth.  On  those  of  the  penis  : Brockhausen,  De  exeretionis  vrince  impedimen- 
ts n vitiis  membri  virilis,  Strasburg,  1781. — Thaut,  De  virgœ  virilis  statu  sano  et 
morbosa , Wurzburg,  1808. — C.  Bell,  Engravings  of  specimens  of  morbid  parts,  Lon- 
don, 1813. — J.  Howship,  Practical  observations  on  the  diseases  of  the  urinary  organs , 
London,  1816. 


OF  THE  GENITAL  SYSTEM. 


455 


4th.  It  is  less  rare  to  find  tire  characters  of  both  sexes  blended  in  the 
same  individual,  one  or  several  parts  of  whom  are  formed  after  the 
type  of  one  sex,  and  the  rest  of  the  body  after  that  of  the  other  sex. 
This  anomaly  essentially  constitutes  hermaphrodism. 

5th.  Alterations  in  texture.  They  are  seen  most  frequently,  and  are 
most  developed,  in  the  genital  organs.  Not  a single  new  formation 
but  has  been  seen  in  some  part  of  the  genital  apparatus,  which  un- 
doubtedly depends  on  the  energy  of  the  formative  power  being 
greater  in  this  than  in  any  other  of  the  organic  systems 


SI,  SPECIAL  ANOMALIES. 

A.  DEVIATIONS  IN  FORMATION. 

I.  HERMAPHRODISM. 

§ 2513.  Hermaphrodism, (\ ) which  constitutes  the  second  class  of 
deviations  of  formation  in  regard  to  quality,  is  indicated  in  the  formation 
of  the  genital  organs,  of  which  alone  we  shall  treat  here,  by  the  forma- 
tion of  one  part  of  the  sexual  system,  after  a type  contrary  to  that  of 
the  rest  or  of  the  whole  body,  that  is,  with  or  without  an  increase  in 
the  organs  of  generation. 

The  second  case  is  infinitely  more  common  than  the  first. 

The  genital  organs  of  the  male  assume  the  characters  of  the  female  : 

1st.  By  the  continuance  of  the  testicle  in  the  abdomen,  and  gene- 
rally by  the  imperfect  disappearance  of  the  primitive  relations  of  lo- 
cality. 

2d.  By  the  interruption  of  the  vas  deferens. 

3d.  By  the  higher  situation,  the  increase  in  volume,  and  enlarge- 
ment of  the  prostate  gland, 

4th.  By  the  smallness  of  the  penis. 

5 th.  By  the  different  degrees  of  its  imperforation. 

6th.  By  the  division  of  the  scrotum,  and  the  existence  between  the 
penis  and  the  anus  of  a canal  similar  to  the  vagina,  varying  in  its  di- 
mensions, which  leads  to  the  prostate  gland,  and  which  is  often  at- 
tended by  one  of  the  three  preceding  anomalies. 

Tth.SBy  the  development  of  one  or  of  the  two  mammae  resembling 
those  of  the  female  in  respect  to  size  and  function. 

The  genital  organs  of  the  female  assume  the  characters  of  the  male  : 

1st.  By  the  hernia  of  the  ovaries  through  the  inguinal  ring. 

(1)  J.  F.  Meckel,  Ueber  die  Zwitterbildungen  ; in  Reil,  Archiv  für  die  Physiolo- 
gie, vol.  xii. — Burdach,  Die  Metamorphose  der  Geschlechter,  oder  Entwichlung  der 
Bildungsstufen  durch  welche  beide  Geschlechter  in  eidander  ubergehen  ; in  his 
Analomische  Xj ntersuchungen,  part  i.  1814. — All  the  works  which  have  appeared  be- 
fore on  the  same  subject  are  mentioned  there. — Seiler,  Observationes J nonnullœ  de 
tcsticulorum  ex  abdomine  in  scrotum  descensu  et  partium  genitalium  anomalis , 
Leipsic,  1787. — J.  Feiler,  Ueber  angeborne  menschliche  Missbildungen , im  allge- 
meinen, und  Hermaphroditen  insbesondere , Leipsic,  1820. 


456 


DESCRIPTIVE  ANATOMY. 


2d.  Perhaps  by  the  adhesion  of  the  tubes  with  these  glands. 

3d.  By  the  smallness  and  sloping  situation  of  the  uterus. 

4th.  By  the  narrowness  and  shortness  of  the  vagina. 

5th.  By  the  enlargement  of  the  clitoris  and  the  extension  of  the 
urethra  to  its  surface. 

6th.  By  the  adhesion  of  the  large  and  small  labia. 

7th.  By  the  imperfect  development  of  the  mammae. 

All  these  anomalies  do  not  necessarily  coexist  in  the  same  organ- 
ism: but  hermaphiodism,  and  the  equivocal  character  of  the  sex 
which  depends  on  them,  are  more  marked,  the  greater  the  number  of 
those  existing. 

Generally  only  one  or  some  of  the  different  parts  of  the  genital  ap- 
paratus are  constructed  after  different  types,  and  the  synonymous  parts 
of  the  two  sides  correspond.  It  is  much  more  rare  to  find  an  herma- 
phrodism  so  perfect  that  each  of  the  two  lateral  faces  present  all  the 
characters  of  a different  sex. 

Finally  the  greatest  degree  of  hermaphrodism  consists  in  the  deve- 
lopment of  some  parts  constructed  after  a sexual  type  contrary  to  that 
of  all  the  others. 

But  few  authentic  instances  of  this  last  and  the  preceding  anomaly 
are  known,  and  they  all  differ  in  respect  to  quality  and  quantity. 

All  these  varieties  of  hermaphrodism  present  more  or  less  distinct 
and  perfect  analogies  with  animals. 

Hitherto,  however,  not  a single  instance  of  human  hermaphrodism 
is  known  where  the  two  sexes  were  so  completely  united  that  it  was 
possible  either  alone  or  with  other  individuals  to  procreate  both  as  a 
male  and  female. 

All  imaginary  reasonings,  however,  cannot  demonstrate  the  impos- 
sibility of  such  a formation,  as  it  exists  in  many  animals,  as  herma- 
phrodites have  been  seen  which  were  very  nearly  in  this  state,  as 
several  phenomena  seem  even  to  prove  that  a perfect  male  organism 
sometimes  possesses  the  creative  power,  independent  of  the  other  sex, 
and  we  cannot  to  a certain  extent  absolutely  refuse  this  power  to  the 
female. 

II.  DEVIATIONS  IN  FORMATION  OF  THE  SPECIAL  GENITAL  ORGANS. 

A.  GENITAL  ORGANS. 

a.  Ovaries  and  tubes. 

§ 2514.  Among  the  primitive  deviations  of  formation  in  the  ovaries 
and  their  excretory  ducts,  the  Fallopian  tubes,  we  remark  the  fol- 
lowing, which  arise  mostly  from  suspended  development  : 

1st.  The  absence  of  an  ovary,  or  more  rarely  of  the  two,  with  or 
without  simultaneous  absence  of  its  tubes. 


OF  THE  GENITAL  SYSTEM. 


457 


2d.  Smallness. 

3d.  The  absence  of  the  vesicles  of  Graaf  in  the  ovaries  of  barren 
women. 

4th.  The  closing  of  the  abdominal  extremity  of  the  tubes. 

This  last  state  is  frequently  developed  after  inflammation  ; it  then 
constitutes  a consecutive  deviation  of  formation. 

Another  anomaly,  which  is  generally  congenital,  but  more  rare, 
consists  in  the  hernia  of  the  ovaries  and  Fallopian  tubes  through  the 
inguinal  ring,  in  which  case  they  resemble  the  testicles. 

b.  Uterus. 

§ 2515.  The  primitive  deviations  in  the  formation  of  the  uterus, 
most  of  which  consist  in  its  suspended  developmental)  are  : 

1st.  Its  total  or  partial  absence.  In  the  latter  case  sometimes  the 
upper  and  sometimes  the  lower  part  is  deficient. 

2d.  Its  smallness,  with  thinness  of  its  parietes. 

3d.  The  continuance  of  its  form  at  a primitive  degree  of  deve- 
lopment. 

Here  exist  several  degrees  which  essentially  consist  most  frequently 
in  a division  into  two  halves.  (2) 

When  the  anomaly  exists  in  the  greatest  degree  possible,  the  uterus 
is  divided  at  its  upper  part  into  two  horns,  and  also  divided  into  two 
halves  by  a septum  at  its  lower  part.  Next  come  two  nearly  equal 
degrees  : sometimes  the  body  of  the  organ  is  extended  into  two  horns, 
and  the  neck  is  single  ; sometimes  the  form  of  the  uterus  is  normal 
externally,  but  its  cavity  is  divided  into  two  halves  at  its  lower  part  by 
a septum.  Next  come  two  other  degrees  ; in  one  a groove  more  or 
less  deep  at  the  bottom  of  the  organ  makes  it  appear  imperfectly  double 
horned,  in  the  other,  it  is  single  externally,  while  its  body  is  divided 
into  two  portions. 

Finally,  when  the  anomaly  is  as  slight  as  possible,  the  form  of  the 
uterus  is  only  more  elongated. 

These  different  degrees  in  the  anomaly  present  very  remarkable 
resemblances  with  the  formations  seen  in  animals,  and  with  animals 
situated  as  much  lower  in  the  scale  as  the  deviation  is  greater. 

Primitive  deviations  of  formation  consisting  in  an  excess  of  the 
formative  power,  are  hardly  known.  The  term  double  uterus (3)  has 
been  wrongly  applied  to  those  which  present  several  of  the  anomalies 
mentioned  by  us. 

The  deviations  in  formation  in  respect  to  quality  which  relate  to 
form  and  situation,  are  rarely  primitive. 

(1)  See  our  Handbuch  der  pathologischen  Anatomie , vol.  i. 

(2)  Thamm  ( loc . cit.)  has  given  a complete  list  of  works  published  on  this  subject. 
— F.  J.  Hunkelmœller,  De  vaginâ  et  utero  duplici,  Berlin,  1818. 

(3)  F.  Tiedemann,  Observation  d’une  grossesse  chez  une  femme  dont  la  matrice 
était  double  ; in  the  Journ.  compl.  des  sc.  méd.,  vol.  vi.  p.  371. — Mad.  Boivin,  Mémo- 
rial de  l’art  des  accouchcmens , p.  85. 


458 


DESCRIPTIVE  ANATOMY 


The  uterus  however  is  sometimes  oblique,  which  state  is  generally 
blended  with  its  obliquity  in  respect  to  situation. (1) 

The  accidental  deviations  of  formation  are  : 

1st.  Abnormal  situation . The  principal  varieties  of  this  anomaly  are 
the  following  : 

a.  The  situation  of  the  uterus  cut  of  the  median  line , in  which  case 
it  generally  rests  against  one  of  the  sides  of  the  pelvis. 

b.  Obliquity , in  which  its  direction  is  from  one  side  to  the  other. 
This  state,  especially  when  the  uterus  is  unimpregnated,  generally 
results  from  adhesions  with  the  adjacent  parts. 

c.  Retroversion ,(2)  in  which  the  longitudinal  diameter  of  the  uterus 
corresponds  to  the  antero-posterior  diameter  of  the  pelvis,  so  that  its 
base  is  directed  downward  and  backward,  and  its  vaginal  orifice  up- 
ward  and  forward.  This  anomaly  occurs  particularly  during  the 
fourth  month  of  pregnancy. 

d.  Prolapsus, (3)  where  the  uterus,  most  frequently  from  an  inver- 
sion of  the  vagina,  descends  more  or  less  into  the  pelvis.  When  the 
vagina  is  entirely  inverted  the  uterus  is  depressed  its  whole  extent, 
and  the  lower  orifice  is  situated  at  the  lower  extremity  of  the  tumor 
formed  by  it  between  the  thighs.  Usually  also  the  neck  is  more  or 
less  elongated,  and  the  uterus  adheres  to  the  primitively  external  face 
of  the  inverted  vagina. 

From  the  elongation  of  the  neck,  however,  the  body  of  this  latter  is 
rarely  situated  on  the  outside  of  the  sac  of  the  vagina.  In  this  de- 
viation of  formation  the  orifice  of  the  uterus  is  rarely  completely 
effaced.  (4) 

Sometimes  the  uterus,  even  when  it  contains  a fetus,  forms  a hernia. 

2d.  Abnormal  form.  One  accidental  anomaly  in  the  formation  of 
the  uterus  connects  it  with  the  proper  deviations  of  formation,  as  it  is 
attended  with  displacement  of  the  organ. 

This  is  inversion, (5)  which  consists  essentially  in  the  turning  out- 
ward of  the  inner  face  of  the  uterus.  It  appears  in  several  degrees, 
for  sometimes  only  the  base  of  the  uterus  approaches  the  orifice,  and 
sometimes  it  projects  through  this  opening.  The  tumor  it  forms  in 
this  latter  case  differs  from  prolapsus,  as  its  lower  part  presents  no 
opening.  This  fact  happens  only  when  the  cavity  of  the  uterus  is 
considerably  distended  and  its  walls  are  proportionally  thin,  and  the 
organ  is  then  compressed  or  drawn  down  by  the  base.  Thus  it  is 
observed  in  parturition,  in  uterine  polypi,  &c. 

SBoer,  Abhandlungen  geburtschûlflichen  Inhalts , vol.  i.  p.  1. 

Cuyper,  De  relroversione  uteri,  Leyden,  1772. — Korscheck,  De  retroverso  utero, 
Halle,  1799. — One  is  figured  in  Hunter,  De  utero  gravido , tab.  xxvi. 

(3)  Bœhmer,  De  prolapsu  et  invcrsione  uteri,  Halle,  1745. — It  is  figured  in  Ruysch, 
Obs.  med.  chir.,  obs.  2 and  8.— Baillie,  Engr.  fase.  ix.  fig.  i. — Clarke,  Diseases  of 
females , London,  1814,  tab.  i-v. 

(41  Bedard  and  Cloquet,  in  the  Bull,  de  lafac.  de  mcd.,  vol.  v.  1816,  p.  114. 

(5)  Van  Sanden,  De  prolapsu  uteri,  Leipsic,  1723.— Saxtorph,  Auszüge  aus  der 
Abhandlungen  der  Copenh.  Gelleschaft,  Halle,  1785. — It  is  figured  in  Ruysch,  Obs. 
anat.  chir.  cent.,  obs.  x.— Denman,  introduction  to  the  praciiec  of  midwifery,  tab. 
xii-xiv.— Baillie,  Engravings,  fasc.  ix.,  fig.  2. 


OF  THE  GENITAL  SYSTEM 


459 


Rupture  is  a deviation  of  formation  of  the  uterus  occurring  under 
similar  circumstances,  although  it  is  rare,  except  in  a state  of  preg- 
nancy ; it  occurs  when  parturition  is  opposed  by  any  cause,  and  is 
seen,  particularly  at  the  lower  part  of  the  organ,  in  a transverse  direc- 
tion. 

The  obliteration  of  the  cavity  of  the  uterus  is  generally  partial,  and 
commonly  occupies  the  lower  part  of  the  organ,  to  a greater  or  less 
extent. 

It  is  sometimes  congenital,  and  may  then  constitute  a primitive  ano- 
maly ; but  it  frequently  supervenes  after  suppuration  and  ulceration. 

c.  Vagina. 

§ 2516.  Sometimes  the  vagina  is  imperforate,  or  is  even  deficient, 
and  a loose  cellular  tissue  exists  in  its  place.  This  anomaly  is  most 
generally  primitive.  Its  least  degree  is  the  closing  of  the  canal,  or  the 
very  great  thinness  and  hardness  of  the  hymen. 

Sometimes  the  vagina  is  divided  in  a greater  or  less  extent  into  two 
halves  by  a longitudinal  septum,  directed  from  before  backward,  so 
that  when  the  division  extends  to  its  lower  extremity  even  two  hymens 
exist.  This  anomaly  may  or  may  not  be  attended  with  an  analogous 
state  of  the  uterus. 

The  vagina  also  presents  primitive  deviations  of  formation  in  respect 
to  length  and  breadth.  In  fact  it  is  sometimes  extremely  narrow  and 
very  short,  which  anomalies  exist  alone  or  together. 

The  most  common  consecutive  deviation  of  formation  is  the  imper- 
fect^) or  perfect  retroversion  of  the  vagina,  attending  the  prolapsus  of 
the  uterus.  The  bladder  is  then  generally  drawn  downward,  and  very 
frequently  also  we  find  calculi,  which  may  sometimes  produce  the 
disease,  and  sometimes  have  been  produced  by  it.(2) 

The  vagina  is  sometimes  ruptured  in  the  same  cases  as  the  uterus, 
but  more  rarely  than  it. 

d.  External  labia. 

§ 2517.  The  external  labia  are  sometimes  deficient,  from  a primi- 
tive deviation  of  formation,  or  adhere  to  each  other  on  the  median  line. 
These  two  anomalies  result  from  the  permanence  of  a primitive  state 
of  formation. 

They  rarely  contain  the  abdominal  viscera  which  have  escaped 
through  the  inguinal  ring, 

(1)  Kaudin,  Mémoire  sur  les  chutes-  partielles  du  vagin;  in  the  Journ.  gén.  de 
méd.,  vol.  lvi.  1816,  p.  259. 

(2)  Ruysch,  Obs.  med.  chir..  obs.  i. — Paget  ( Lond . med.  andphys.  Journ.,  vol.  vi, 
p.  391)  mentions  a stone  weighing  twenty-seven  ounces,  attended  with  several 
smaller  ones,  found  in  a case  of  prolapsus  of  the  bladder. 


460 


DESCRIPTIVE  ANATOMY. 


Sometimes  they  enlarge  very  much,  either  suddenly,  from  the  me- 
tastasis of  other  diseases,  particularly  blenorrhea,  or  slowly  and  gra- 
dually. 

e.  Internal  labia. 

§ 2518.  Sometimes  also  the  nymphæ  are  deficient,  or  adhere. 
These  two  states  may  be  primitive  or  accidental,  and  developed  after 
an  inflammation.  In  some  cases  they  present  an  opposite  anomaly, 
and  are  double  or  even  triple.(l)  Their  unusual  enlargement  is  com- 
monly consecutive  or  accidental. 

f.  Clitoris. 

2519.  The  clitoris  is  sometimes  unusually  large,  and  then  resem- 
bles the  penis  in  the  male,  particularly  when  the  urethra  extends 
unusually  far  forward.  Sometimes  this  part  is  enlarged  in  conse- 
quence of  syphilitic  affections,  and  its  texture  is  altered  ; it  then  be- 
comes harder,  firmer,  and  irregular. 

Its  fissure  is  an  anomaly  interesting  as  analogous  with  animals. 

B.  GENITAL  ORGANS  IN  THE  MALE. 

a.  Testicles. 

§ 2520.  The  deviations  in  the  formation  of  the  testicles  are  : 

1st.  The  absence  of  one  of  these  two  organs,  which  must  be  distin- 
guished from  its  apparent  absence,  depending  on  the  gland  continuing 
in  the  abdomen. 

2d.  Smallness. 

3d.  Permanence  in  their  primitive  situations.  This  anomaly  pre- 
sents a great  many  degrees,  from  the  case  where  the  testicle  remains 
below  the  kidney  to  that  where  the  canal  of  communication,  which 
continu es^some  time  after  leaving  the  abdomen,  is  imperfectly  oblite- 
rated. This  last  deviation  of  formation  becomes  the  cause  of  conge- 
nital inguinal  hernia. 

4th.  The  interruption  of  the  vas  deferens,  its  termination  in  a cul- 
de-sac,  the  absence  of  the  seminal  vesicles. (2) 

5th.  The  plurality  of  the  testicles.  This  anomaly  is  very  doubtful. 
The  seminal  vesicles  also  are  rarely  more  than  two  in  number.(3) 

The  consecutive  deviations  of  formation  are  : 

1st.  Abnormal  enlargement. 

2d.  Atrophy. 

(1)  Neubauer,  Dc  Iriplici  nympliarum  ordine,  Jena,  1774. 

(2)  See  our  Handbuch  der  pathologischen  Anatomie,  vol.  L,  p.  685. — H.  Bosch* 
Diss.  sistens  obscrvalioncm  de  vcsiculæ  seminalis  sinislræ  dejectu , integris  lestibus , 
vase  vero  deferente  sinislro  clauso,  Leyden,  1813. — Seiler  haa  published  an  excellent 
account  of  the  post-mortem  examination  of  a person  affected  with  cryplorchis. 

(3)  Meckel,  Dc  duplicitate  monslrosa,  in  Hundbuch  der  pathologischen  Anatomic, 
vol.  ii.  p.  32. 


OF  THE  GENITAL  SYSTEM. 


461 


These  two  states  are  most  frequently  attended  with  alterations  of 
texture. 


b.  Prostate  gland. 

§ 2521.  The  prostate  gland  is  particularly  subject  to  enlargement, 
which  is  sometimes  attended  with  a change  in  its  tissue.  In  this  case 
it  is  usually  said  to  have  become  schirrous  ; this  assertion  is  true  some- 
times, but  not  always.  Hypertrophy  of  the  prostate  gland  often 
depends  on  the  development  in  its  substance  of  fibrous  or  fibro-cartila- 
ginous  formations,  which  are  also  as  commorÉtn  its  corresponding 
organ,  the  uterus.(l) 

The  middle  lobe  of  the  prostate  gland  is  often  swelled  abnormally  ; 
but  this  swelling  does  not  always  exist,  which  is  contrary  to  Home’s 
assertion. 

c.  Penis. 

§ 2522.  The  penis  presents  a great  number  of  primitive  deviations 
of  formation,  which  depend  principally  on  a suspension  of  develop- 
ment, or  the  permanence  of  a primitive  form.  They  are  : 

1st.  Absence. 

2d.  Smallness. 

3d.  Total  or  partial  imperforation,  which  presents  several  differ- 
ences, either  in  respect  to  the  degree  or  the  quality,  from  the  closing 
of  the  prepuce  to  the  opening  of  the  urethra  in  the  perineum,  which  is 
or  is  not  attended  with  the  abnormal  smallness  of  the  penis  ; in  this 
case  the  lower  part  of  the  urethra,  and  consequently  of  the  penis,  are 
in  fact  cleft  on  their  lower  face. (2) 

4th.  The  narrowness  of  the  prepuce,  or  phymosis,  which  is  gene- 
rally accidental. 

5th.  The  fissure  of  the  penis  at  its  upper  face,  which  is  often  at- 
tended with  that  of  the  bladder,  and  which  when  existing  alone  makes 
the  transition  from  this  latter  anomaly  to  the  normal  formation. 

6th.  The  complete  division  of  the  penis  into  two  halves.  This  de- 
viation of  formation  is  much  more  rare  than  the  preceding. (3) 

On  the  other  hand,  sometimes  the  penis  is  more  or  less  perfectly 
double. 

Perhaps  we  ought  to  consider  as  the  first  degree  of  this  anomaly, 
the  entire  separation  of  the  urinary  and  seminal  passages,  which  has 
sometimes  been  observed. 

(1)  Dupuytren,  Sur  les  calcules  de  la  prostate;  in  the  Bull,  de  lafac.  de  méd..  vol. 
vii.,  p.  135. 

(2)  Sixtus,  De  dijßsione  genitalium,  Wurtzburg,  1813. 

Ij3j  Bamberger,  De  intussusceptione  membrance  urethrce  internee,  Wurtzburg, 

Vol.  III. 


59 


462 


descriptive  anatomy. 


When  the  organ  is  perfectly  double,  the  two  penises  are  situated 
one  at  the  side  of  or  one  above  the  other.  This  last  anomaly  presents 
a remarkable  analogy  with  the  doubling  of  the  tongue,  the  organ 
which  corresponds  to  the  penis.  The  first  might  be  regarded  as  a 
greater  development  of  the  fissure  of  the  penis. 

The  consecutive  deviations  of  formation  comprehend  the  unusual 
enlargement  of  the  penis,  which  commonly  supervenes  after  the  deve- 
lopment of  accidental  formations. 

The  internal  membrane  of  the  urethra  is  rarely  reversed.(l) 

C.  MAMMS. 

<5  2523.  The  mammae  are  sometimes  deficient  on  one  side,  or  on 
both. 

Their  unusual  smallness  in  the  female  and  their  abnormal  size  in 
the  male  constitute  the  first  degree  of  hermaphrodism,  especially  when 
in  the  second  case  they  secrete  milk. 

Sometimes  they  are  multiplied  as  in  the  mammalia.  In  the  first 
degree  of  this  anomaly  one  mamma  has  two  nipples  : next  we  find 
several  mammae  one  above  another,  two  and  even  three  on  each  side, 
or  on  one  only.* 


B.  ALTERATIONS  IN  TEXTURE. 


A.  GENITAL  ORGANS  IN  THE  FEMALE. 

§ 2524.  Of  all  the  parts  of  the  genital  system,  alterations  of  texture 
exist  most  frequently  in  the  ovaries  ; here  too  the  most  different  and 
the  most  regular  new  formations  appear.  The  increase  in  the  size  of 
the  ovaries  must  generally  be  attributed  to  the  formation  of  these  acci- 
dental productions,  although  it  is  sometimes,  especially  at  first,  only 
simple  hypertrophy,  either  in  the  whole  substance  of  the  gland,  or,  as 
is  more  frequent,  of  one  of  its  constituent  parts,  the  vesicles.  The  en- 
largement of  the  ovary  is  often  enormous,  and  to  such  an  extent  that 
the  organ  has  been  found  weighing  fifty- five, (2)  eighty -five,  and  even 
one  hundred  and  two  pounds. (3) 

(1  ) Stiebe],  Männliches  Hymen;  in  the  Deutsches  Archiv.  Jüt  die  Physiologie, 
vol.  viii.  p.  207. 

* Sometimes  the  supernumerary  mamma;  exist  in  unusual  parts  of  the  body.  Dr. 
Roberts  mentions  a woman  in  whom  a third  mammae  existed  in  the  groin, with 
which  she  suckled  several  children. 

(2)  Normand,  Observation  sur  la  transformation  d’un  ovaire  ; in  the  Journ.  gen. 
de  méd.,  vol.  lvi.,  p.  145. — Valentin,  ibid.,  vol.  lviii.,  p.  218.  _ 

(3)  Van  den  Bosch,  in  Voigtei,  Handbuch  der  pathologischen  Anatomie , vol.  in. 
p.  641. 


OF  THE  GENITAL  SYSTEM. 


463 


The  least  abnormal  formation  of  this  kind  is  dropsy  of  the  ovary. (1) 
This  state  presents  some  differences.  Sometimes,  in  fact,  the  liquid  is 
contained  in  one  pouch,  sometimes  it  fills  several  vesicles,  of  various 
sizes.  It  also  differs  much  not  only  in  respect  to  quantity,  -which  is 
often  enormous,  but  also,  and  even  sometimes  in  the  different  cysts  of 
the  same  ovary,  in  respect  to  color,  consistence,  &c. 

The  cysts  generally  adhere  to  the  substance  of  the  ovary  ; but  we 
frequently  also  find  them  entirely  loose  and  very  numerous  in  the 
cavity  of  this  organ,  where  they  seem  to  have  been  produced  by  an 
effusion  of  serum.  This  morbid  alteration  depends  sometimes  on  the 
increase  of  the  vesicles  of  Graaf,  sometimes  on  a repetition  of  these 
vesicles  resembling  the  effects  of  generation,  and  consequently  in  a 
formation  of  serous  membranes. 

Not  unfrequently  these  serous  membranes  contain  fat  or  adipocire. 

Beside  the  serous  membranes,  accidental  mucous  membranes  are 
often  developed  in  the  ovaries  ; these  also  have  the  form  of  cysts,  con- 
tain a more  or  less  dense  fluid,  and  belong  to  the  class  of  atheromata 
or  melicerides. 

Another  alteration  in  texture  of  the  ovary,  which  frequently  is  seen 
alone  or  attended  with  the  preceding,  is  the  formation  of  fibrous,  fibro- 
cartilaginous, cartilaginous,  or  osseous  substance,  which  is  frequently 
developed  in  very  large  rounded  masses,  and  also  increases  the  weight* 
and  size  of  the  organ.  To  this  we  must  refer,  if  not  entirely  at  least 
in  great  part,  the  formations  described  as  steatoma,  sarcoma,  scihrrus, 
osteo-sarcoma,  and  ossification  of  the  ovary. 

To  these  abnormal  repetitions  of  normal  tissues,  which  frequently 
occur  also  ift  the  other  parts  of  the  body,  but  much  less  commonly 
than  in  the  ovaries,  we  must  add  another,  which  is  almost  if  not  en- 
tirely peculiar  to  these  glands.  We  mean  the  hairs  and  the  teeth. (2) 
The  hairs  are  much  more  frequent  than  the  teeth,  and  are  developed 
in  the  fat,  and  the  teeth  in  the  midst  of  cysts  filled  with  a gelatinous 
mass,  so  that  here  the  normal  type  is  perfect,  both  in  respect  to  the 
organ  where  the  new  formation  occurs,  as  in  that  of  the  proportional 
frequency  of  its  appearance. 

The  nature  of  the  organ  in  which  these  productions  of  bone,  hair, 
and  teeth  occur,  and  which  is  the  workshop  of  generation,  the  period 
of  life  at  which  they  are  most  frequently  developed,  the  fact  that  they 
have  often  been  preceded  by  coition,  finally  the  numerous  cases  of 
ovarian  dropsy,  have  led  many  physiologists  to  consider  them  as  the 
remains  of  a fetus  which  is  developed  in  the  ovary.  But  this  hypo- 


(1)  Fehr,  De  virgine , hydrope  ovarii  laborante,  Strasburg-,  1762. — Huth,  Casus 
rirginis  hydrope  ovarii  extinclce,  Strasburg,  1768. — Murray,  De  hydrope  ovarii , 
Upsal,  1780. — Rossum,  De  hydrope  ovariorum,  Louvain,  1782. — Julia-Fontenelle, 
Analyse  de  quelques  substances  contenues  dans  les  ovaires  dans  certains  états  morr 
bides  ; in  the  Archiv,  gén.  de  méd.,  vol.  iv.,  p.  257. 

(2)  J.  F.  Meckel,  Mémoire  sur  les  poils  et  les  dents  qui  se  dévelloppent  acciden- 
tellement dans  le  corps  ; iu  the  Journ.  compl.  du  diet,  des  sc.  méd.,  vol.  iv.  p,  122 
and  217. 


464 


DESCRIPTIVE  ANATOMY. 


thesis  is  absolutely  inadmissible  : for  the  total  disparity  often  observed 
in  respect  to  number,  form,  and  size,  between  these  abnormal  produc- 
tions, and  the  remarkable  fact  that  the  hair,  the  bones,  and  the  teeth 
are  the  only  parts  found  thus,  while  in  extraordinary  pregnancies  all 
the  parts  of  the  fetus  are  long  preserved,  prove  also  that  the  act  of 
generation,  if  necessary  to  produce  them,  has  not  at  least  given  rise  to 
a perfect  fetus,  and  is  confined  to  developing  the  parts  there  found. 

Although  in  many  cases  the  development  of  these  more  perfect 
formations,  and  also  of  all  the  other  abnormal  formations  seen  in  the 
Gvary,  undoubtedly  arises  from  a copulation  not  sufficient  to  give  rise 
to  a normal  organism,  on  account  of  the  unhealthy  state  of  one  or 
of  both  the  parents,  their  advanced  age,  or  any  other  cause  which 
weakens  in  them  the  power  of  generation  : we  cannot,  however,  admit 
that  the  male  is  necessary  to  produce  them,  since  they  have  been 
found  in  very  young  girls,  where  the  genital  organs  were  perfectly 
untouched,  and  they  have  occurred  in  other  parts  of  the  body  not  only 
of  the  female  but  in  the  male. 

If  they  are  more  common  and  more  perfect  in  the  ovary  than  in  any 
other  of  the  organs,  it  is  because  the  formative  power  is  more  energetic 
in  this  gland.  We  must  not  conclude  from  this  that  the  union  of  the 
sexes  must  necessarily  have  preceded  them,  and  still  less  are  they  the 
remnant  of  an  ovarian  fetus. 

The  entirely  abnormal  alterations  of  texture  are  much  more  rare  in 
the  ovary,  probably  for  the  same  cause,  and  because  from  the  greater 
energy  of  the  formative  power,  attempts  to  create  new  formations  are 
there  more  frequently  successful. 

An  extremely  rare  alteration  in  respect  to  form,  belonging  exclu- 
sively to  the  ovary,  and  the  nature  of  which  has  not  yet  been  exa- 
mined, is  a large  arborescence,  formed  of  several  solid  tubercles  united 
by  filaments.  This  anomaly  has  been  observed  by  Prochaska.(l) 

Otto  has  seen  an  analogous  production,  which  was  not  an  inch  in 
size.  (2) 

We  also  have  before  us  two  instances,  which  are  recent.  In  opening 
the  cadaver  of  a prostitute  aged  about  thirty  years,  in  whom  were 
traces  of  an  inflammation  of  the  ovary,  we  found  the  tubes  adherent 
and  very  thick,  and  farther  the  left  ovary  considerably  enlarged,  very 
soft,  and  changed  into  numerous  eminences  of  different  figures.  In 
another  cadaver  of  a woman  forty  years  old,  on  the  surface  of  the  right 
ovary  were  three  cysts  about  four  lines  in  diameter,  the  inner  face  of 
which  was  very  much  folded,  and  presented  similar  circumvolutions. 
The  first  case  was  very  probably  the  formation  described  by  Prochaska, 
which  perhaps  might  have  appeared  in  the  second,  if  the  cysts  had 
been  torn,  and  their  inner  face  had  vegetated. 

§ 2525.  Alterations  in  the  texture  of  the  uterus  are  very  frequent. 

(1)  Disquis.  organism,  anat.  phys.,  § 58,  tab.  v. 

(2)  Handbuch  der  pathologischen  Anatomie,  p.  378,  note  3. 


OF  THE  GENITAL  SYSTEM. 


465 


Among  the  abnormal  repetitions  of  normal  tissues  we  may  mention 
principally  the  fibrous,  fibro-cartilaginous,  or  osseous  bodies,  which 
must  be  distinguished  from  schirrus,  although  they  have  frequently 
been  described  as  such,  on  account  of  their  hardness. 

These  productions  are  rounded,  sometimes  distinct,  sometimes  united 
in  great  numbers,  and  adhere  but  slightly  to  the  substance  of  the 
uterus.  They  generally  appear  on  its  external,  but  sometimes  on  its 
internal  face,  and  have  a yellowish  white  tint,  and  an  irregular  or 
more  or  less  evidently  fibrous  structure.  They  commonly  ossify  in 
some  parts,  although  their  volume  has  no  effect  on  this  phenomenon. 
They  then  become  sometimes  extremely  hard,  so  that  they  are  cut 
with  difficulty.  They  are  seen  principally  about  the  middle  of  life  in 
unmarried  females  who  have  not  borne  children. 

Hairs  and  fat  are  formed  more  rarely  under  similar  circumstances 
in  the  substance  of  the  uterus. 

All  these  formations  and  even  the  teeth  are  sometimes  developed 
also  on  the  inner  face  and  in  the  cavity  of  the  uterus.  (1) 

The  circumstances  in  which  they  occur  in  the  last  two  places  allow 
them  to  be  considered  as  the  imperfect  products  of  generation.  Those 
in  the  substance  of  the  uterus  are  most  frequently  developed  without 
the  co-operation  of  the  male,  although  they  may  be  caused  also  by 
copulation.  In  this  respect  they  resemble  the  abnormal  formations  of 
the  ovary.  It  is  very  curious  that  the  phenomena  caused  by  them  in 
both  organs  sometimes  resemble  those  of  pregnancy. (2) 

Not  unfrequently  even  in  these  same  circumstances  other  formations 
are  developed  in  the  cavity  of  the  uterus,  which  may  be  considered  as 
resulting  from  an  ineffectual  effort  to  produce  a new  organism,  and 
which  resemble  either  the  deciduous  membrane,  or,  when  they  have 
the  form  of  thin  vesicles  filled  with  a serous  fluid,  the  inner  membranes 
of  the  ovum. 

The  entirely  abnormal  alterations  in  the  texture  of  the  uterus  are: 
1st.  Schirrous  and  cancerous  formations. (3)  This  alteration  does 
not  appear,  like  the  fibrous  bodies,  in  the  form  of  distinct  masses  ; it  is 
formed  by  a change  which  generally  commences  at  the  lower  part  of 
the  organ,  and  which  gradually  extends  to  the  whole  of  it.  The  parts 
in  which  it  is  situated  become  at  first  hard,  then  swell  more  or  less, 
afterwards  suppurate  in  the  same  order,  and  are  thus  gradually  de- 
stroyed ; abnormal  openings  are  thus  formed  which  communicate  with 
the  cavity  of  the  abdomen,  the  bladder,  or  the  rectum,  or  with  several 
of  these  parts  at  once.  Here  as  in  all  other  cases  of  this  change,  the 
lymphatic  system  is  infected,  and  death  is  the  necessary  consequence, 

<i)  Sec  our  Handbuch  der  pathologischen  Anatomie,  vol.  i.  p.  525-542. 

(2)  Cochon-Dupuis,  in  the  Mém.  de  Paris,  1698,  p.  339.— A.  Monro,  Four  cases  of 
the  tumefied  ovarium  ; in  the  Med.  essays  of  JEdinb.,  vol.  vi.,  p.  278.— In  two  cases 
pains  supervened  ; in  the  first  at  nine  months,  in  the  other  at  ten. 

(3)  Patrix,  Traité  sur  le  cancer  de  la  matrice  et  sur  les  maladies  des  voies  uri- 
naires,  Paris,  1820. 


466 


DESCRIPTIVE  ANATOMY. 


All  these  characters  distinguish  them  from  the  fibrous  and  osseous 
productions.* 

2d.  Polypi  are  developed  on  the  inner  face  of  the  uterus  so  fre- 
quently that,  in  twenty  cadavers,  Portal  has  found  them  in  thirteen. (1) 
They  are  distinguished,  according  to  the  place  where  they  exist,  into 
polypi  of  the  base,  of  the  body,  and  of  the  neck  : and  according  to  then- 
degree  of  solidity  into  soft  and  hard.  They  vary  much  in  respect  to 
number  and  volume. 

The  vagina  usually  participates  in  the  schirrus  of  the  uterus,  at 
least  at  its  upper  part.  Polypi  also  are  developed  there,  particularly 
at  its  summit,  but  much  more  rarely  than  in  the  uterus. 

Sometimes  hairs  grow  on  the  inner  face  of  the  external  labia. 

B.  GENITAL  ORGANS  OF  THE  MALE. 

§ 2526.  The  alterations  in  the  texture  of  the  testicles  are  princi- 
pally : 

1st.  Induration,  a consequence  of  inflammation. 

2d.  Dropsy  of  the  vaginal  tunic,  termed  hydrocele.  This  disease  is 
common.  The  liquid  is  commonly  serous  and  limpid  ; but  sometimes 
also  instead  of  serum  we  find  a solid  and  opaque  substance,  or  when 
this  liquid  is  thicker  and  more  viscous  than  usual,  it  contains  shining 
laminae  very  similar  to  the  fatty  substance  of  cholesterine,  but  which 
differ  from  it,  as  their  specific  gravity  is  greater,  and  they  dissolve  more 
readily  in  the  alkalies. (2) 

3d.  Ossification,  which  is  situated  principally  in  the  epididymis  and 
the  vaginal  tunic.  We  not  unfrequently  find  in  the  albugineous  mem- 
brane rounded  plates  of  bone  and  cartilage,  which  are  finally  detached, 
and  become  loose  in  the  cavity  of  the  vaginal  tunic.  These  produc- 
tions are  less  common  in  the  spermatic  cord. 

4th.  Hairs  are  very  rarely  developed  in  them. 


* Very  recently  the  mollescence  of  the  uterus  has  been  made  the  subject  of  re- 
search. In  an  article  on  this  subject  by  Dr.  Luroth,  we  make  the  following  extract 
in  regard  to  this  disease: 

He  states  that  mollescence  of  the  uterus  is  more  frequently  partial  than  general  ; 
it  more  commonly  occupies  the  internal  surface  and  the  cervix,  though  it  occasion- 
ally extends  through  the  substance  of  the  organ.  The  mollescence  presents  several 
degrees,  blending  insensibly  with  each  other.  In  the  first,  the  parts  are  simply 
softened  or  very  flaccid,  generally  with  serous  or  sero-sanguineous  infiltration  into 
the  nterstices.  In  the  second  degree,  the  structure  of  the  uterus  is  still  farther  al- 
tered. It  will  scarcely  bear  handling  without  reduction  into  a pultaceous  mass.  In 
the  third  degree,  the  disorganization  amounts  almost  to  a liquefaction  or  reduction 
of  the  viscus  to  an  inorganic  pulp. — (Am.  Journ.  of  the  Medical  Sciences , for  No- 
vember, 1828.) 

(1)  Observations  sur  la  structure  des  parties  de  la  génération  clans  la  femme  ; in 
the  Mem.  de  Paris,  1770,  p.  190. — C.  Mayer,  Diss.  de  polypis  uteri,  Berlin,  1820. 

(2)  Beclard  and  Cloquet,  Deux  observations  d' hydrocèles  rares  ; in  the  Bull,  de  la 
fac.  de  méd.,  vol.  v.  p.  38. 


OF  THE  ABDOMINAL  CAVITY. 


467 


5th.  The  albuminous  and  tuberculous  formations  in  the  substance 
of  these  glands  are  not  rare. 

6th.  We  find  also  schirrous  formations,  which  change  into  cancer. 

7th.  Fungous  formations. 

8th.  Cysts  filled  with  a liquid  similar  to  the  serum  of  the  blood. 

Sometimes,  but  rarely,  calculi  form  in  the  seminal  vesicles,(l)  or  in 
the  prostate  gland. (2)  The  latter  at  least  are  composed  of  phosphate 
of  lime. 

The  alterations  in  the  texture  of  the  penis  are  usually  of  syphilitic 
origin,  ulcers,  warts,  &c. 

C.  MAMMÆ. 

§ 2527.  The  mammæ  of  the  male  are  subject  to  but  few  diseases. 
The  alteration  most  frequent  in  those  of  the  female  is  schirrus.  We 
however  designate  by  this  term  new  formations,  however  much  they 
differ,  for  almost  all  can  be  developed  either  alone  or  with  others,  in 
the  tissue  of  the  mammary  gland.* 


CHAPTER  Y. 

OF  THE  ABDOMINAL  CAVITY. 


ARTICLE  FIRST. 

ABDOMINAL  CAVITY  IN  THE  NORMAL  STATE, 

A.  PERFECT  STATE. 

I.  ABDOMINAL  CAVITY  IN  GENERAL. 

§ 2528.  After  describing  the  digestive,  the  respiratory,  the  urinary, 
and  the  genital  systems,  we  proceed  to  the  topography  of  the  abdo- 
minal cavity, (3)  the  general  characters  of  which  have  already  been 
mentioned.  (4) 

(1)  Hartmann,  De  calculis  in  vesicula  seminali,  Erfort,  1765, 

(2)  Pohl,  De  calculis  in  prostata  invenlis,  Leipsic,  1737. 

* An  abnormal  formation  in  the  mammæ  which  is  not  common  is  that  of  hyda- 
tids, one  case  of  which  is  detailed  in  the  Am.  Journ.  of  the  Medical  Sciences  for  No- 
vember, 1825. 

(3)  Fantoni,  De  musculis  abdominis,  peritonceo,  vasis  ombilicalibus  et  omento, 
Turin,  1745. 

(4)  Vol.  i.  p.  151. 


468 


DESCRIPTIVE  ANATOMY. 


A.  COMPOSITION. 

§ 2529.  The  upper  wall  is  formed  by  the  diaphragm  ; the  posterior , 
in  the  centre,  by  the  lumbar  vertebra  and  the  sacrum,  on  the  sides  by 
the  psoas  magnus  and  the  posterior  part  of  the  two  broad  internal 
abdominal  muscles  : each  side  is  constituted  above  by  the  middle  por- 
tion of  these  two  muscles,  and  the  posterior  part  of  the  obliquus  ab- 
dominis externus,  below  by  the  ossa  ilia  and  the  descending  ramus  of 
the  ischium,  the  anterior  by  the  anterior  part  of  the  broad  abdominal 
muscles,  the  rectus,  the  pyramidalis,  the  linea  alba,  the  pubis,  and  its 
ascending  ramus.  The  inferior  by  the  muscles  of  the  perineum. 

The  parts  we  have  mentioned  are  covered  on  the  inside  directly  or 
indirectly  by  the  peritoneum. 

Hence  the  abdominal  parietes  are  most  solid  in  the  posterior  and  in- 
ferior parts.  We  mayjudge  also  from  the  description  of  the  mùscles 
which  form  them,  that  these  also  are  enveloped  in  some  parts  more  per- 
fectly than  in  others.  In  the  latter,  the  muscular  layers  are  thinner 
and  more  feeble,  or  the  muscles  and  their  tendons  are  here  entirely  or 
in  great  part  deficient. 

B.  FORM. 

§ 2530.  Considered  generally,  the  form  of  the  cavity  of  the  abdo- 
men is  oval.  The  umbilicus  is  situated  at  about  the  centre  of  its  an- 
terior face  : the  half  above  this  cicatrix  is  a little  larger  and  broader 
than  the  lower.  The  anterior  wall  is  the  longest.  The  sides  are  very 
short  and  almost  straight.  The  posterior  presents  inequalities  produced 
by  the  projection  of  the  lumbar  vertebrae  and  the  sacrum.  It  is  con- 
vex in  the  centre,  at  its  upper  part,  and  concave  on  the  sides,  particu- 
larly below.  The  upper  and  lower  faces  are  more  or  less  concave. 

c.  DIMENSIONS. 

§ 2531.  The  abdominal  cavity  is  much  larger  than  the  thoracic  : it 
is  the  most  extensive  of  the  three  splanchnic  cavities. 

D.  CHANGES  IN  FORM  AND  SIZE. 

§ 2532.  As  its  parietes  are  formed  mostly  by  muscles,  it  can  vary 
much  in  form  and  size.  The  most  important  change  is  that  which 
occurs  regularly  and  constantly  during  respiration,  and  which  depends 
on  the  alternate  contraction  and  relaxation  of  the  diaphragm.  The 
action  of  the  abdominal  muscles  also  occasionally  contract  it  more  or 
less,  to  expel  the  substances  contained  in  the  intestinal  canal,  the 
uterus,  and  even  in  the  bladder.  The  diaphragm  and  the  other  abdo- 


OF  THE  ARDOMINAL  CAVITY. 


469 


minai  muscles  are  generally  antagonists.  Their  simultaneous  action 
exerted  in  straining,(l)  produces  the  greatest  possible  contraction. 

The  abdominal  cavity  is  unusually  distended  : 

1st.  By  every  thing  which  normally  or  abnormally  increases  the 
mass  or  the  volume  of  the  parts  it  contains. 

2d.  By  the  direct  accumulation  within  it  of  substances  of  every 
kind,  the  origin  of  which  varies  infinitely. 

In  this  case  all  the  parts  which  form  its  parietes  are  generally  uni- 
formly distended. 

§ 2533.  Besides  the  organs  we  have  mentioned  above,  the  abdomi- 
nal cavity  also  contains  the  lower  part  of  the  aorta,  the  ascending  vena- 
cava,  the  commencement  of  the  thoracic  canal,  the  great  iliac  trunks, 
the  lower  part  of  the  ganglionnary  nerve,  and  the  lumbar  and  iliac 
plexuses  of  the  last  spinal  nerves. 

All  these  parts  are  attached  more  or  less  by  cellular  tissue  and  in  a 
larger  or  smaller  part  of  their  parietes,  especially  with  the  posterior,  less 
to  the  superior,  still  less  to  the  inferior,  the  anterior,  and  the  lower  re- 
gion of  the  side  ; the  upper  region  of  the  selatter  and  of  the  anterior, 
is  entirely  loose,  except  a small  portion  of  the  anterior,  to  which  the 
suspensory  ligament  of  the  liver  is  attached. 

Even  where  there  is  no  continuity  between  the  containing  parts  and 
those  contained,  the  external  faces  of  these  latter  are  in  direct  contact 
with  the  internal  face  of  the  abdominal  parietes,  so  that  these  faces  can 
glide  or  play  upon  each  other. 

As  to  their  situation,  the  parts  contained  in  the  abdominal  cavity 
differ  principally  in  this  respect,  that  most  of  them,  viz.  the  upper  region 
of  the  genital  system  of  the  female,  and  the  whole  digestive  apparatus 
except  the  pancreas  and  the  lower  extremity  of  the  rectum,  are  con- 
tained in  the  peritoneum,  while  the  others,  especially  the  great  vascu- 
lar and  nervous  trunks,  the  urinary  organs  and  the  lower  part  of  the 
genital  system,  are  situated  out  of  this  membrane. 


II.  PERITONEUM. 

§ 2534.  The  peritoneum, (2)  the  largest  and  the  most  complex  se- 
rous membrane  in  the  body,  has  a fibro-serous  structure  in  some  parts. 
It  forms  a sac,  closed  in  every  part  except  at  the  abdominal  orifices  of 


(1)  J.  Cloquet,  De  l'influence  des  efforts  sur  les  organes  renfermés  dans  la  cavité 
thoracique,  Paris,  1820. 

(2)  Wedel,  De  peritonœo,  Jena,  1696.— J.  Douglas,  Description  of  the  peritoneum 
and  ofthat  part  of  the  membrana  cellular  is  which  lies  on  its  outside , with  an  account 
of  all  the  abdominal  viscera,  London,  1730. — C.  G.  Buttner,  De  peritonœo,  Königs- 
berg-, 1738. — F.  G.  Hewsing-,  De  peritonœo,  Giessen,  1742. — H.  A.  Wrisberg,  Deperi- 
tonœo  diverticulis,  illisque  imprimis,  quee  per  ombilicum  et  lineam  albam  contingunt, 
Gotting-en,  1780. — A.  Vacca-Berlinghieri,  Mémoire  sur  la  structure  du  péritoine  et 
sur  ses  rapports  avec  les  viscères  abdominaux  ; in  the  Mémoires  de  la  soc.  méd. 
d'émul.,  vol.  iii.  p.  315. — C.  J.  M.  Langenbeck,  Commentarius  de  structura  peri- 
tonœi,  testiculorum  tunicis,  eorumque  ex  abdomine  in  scrotum  descensu,  ad  illustran- 
dam  herniarum  indolem,  Gottingen,  1817.. 

Vol.  III.  " 60 


470 


DESCRIPTIVE  ANATOMY. 


the  two  Fallopian  tubes,  where  it  is  continuous  with  the  mucous  mem- 
brane of  these  passages.  It  covers  almost  the  whole  cavity  of  the  ab- 
domen, except  at  the  lowest  part  of  the  pelvis,  and  like  all  the  serous 
membranes,  it  covers  in  two  different  modes  the  parts  on  the  surface  of 
which  it  passes.  In  fact,  1st,  it  envelops  them  all  with  its  external 
layer,  which  has  the  form  of  a sac,  but  does  not  touch  them  ; 2d, 
Its  inner  layer  is  reflected  in  several  places,  and  is  fitted  to  the  surface 
of  the  parts,  and  forms  their  external  envelop. 

Several  anatomists  assert,  that  not  only  the  parts  enumerated  above, 
but  also  all  those  situated  in  the  abdomen,  are  contained  in  the  peri- 
toneum, which  divides  into  an  external  and  an  internal  layer  to  em- 
brace them.  This  opinion  arises  from  another,  that  the  condensed 
cellular  tissue  on  the  outer  face  of  the  peritoneum,  is  a special  fold  of 
this  membrane.  But  we  cannot  admit  it,  since  this  layer  is  not  serous; 
it  exists  in  every  part  ; it  does  not  come  from  the  division  of  the  proper 
serous  fold  of  the  peritoneum,  but  it  is  formed  by  the  scalpel,  particu- 
larly when  the  parts  are  hardened  by  immersion  in  alcohol. 

§ 2535.  Like  all  serous  membranes,  the  peritoneum  is  highly  ex- 
tensible, so  that  it  does  not  tear  when  suddenly  or  gradually  extended 
very  much.  Its  solidity  in  the  normal  state  depends  upon  this  property. 

It  is  not  equally  firm  in  every  part.  The  external  layer  is  generally 
much  stronger  and  thicker  than  the  internal.  It  is  strongest  in  the 
lumbar  region,  and  at  its  lower  and  anterior  part,  and  is  weakest  at  its 
upper  part. 

As  its  connections  with  the  abdominal  parietes  are  generally  slight, 
it  yields  easily  when  drawn  down,  so  that  its  situation  and  its  relations 
with  the  adjacent  parts  change  in  a greater  or  less  extent,  when  the 
testicles  descend  into  the  scrotum,  or  when  a hernia  exists, 

A.  EXTERNAL  FOLD  OF  THE  PERITONEUM. 

§ 253G.  We  may  distinguish  in  the  external  fold  of  the  peritoneum, 
four  parietes,  an  anterior,  a superior,  a posterior,  and  an  inferior,  the 
external  faces  of  which  arc  almost  in  every  part  united  to  the  internal 
face  of  the  abdominal  parietes. 

A.  ANTERIOR  WALL. 

§ 2537.  The  anterior  wall  covers  the  posterior  face  of  the  linea 
alba,  the  common  anterior  tendons  of  the  broad  muscles  of  the  abdo- 
men, and  the  anterior  part  of  the  fleshy  portion  of  the  transversalis 
muscle.  It  is  attached  rather  loosely  to  the  linea  alba,  adheres  inti- 
mately to  the  anterior  tendon,  and  is  connected  less  firmly  with  the 
fleshy  portion  of  the  transversalis  muscle.  It  is  serous  only  at  its  lower 
part:  but  above  it  is  covered  on  the  outside  by  a very  apparent  layer  of 
transverse  and  strong  fibres,  entirely  distinct  from  those  of  the  tendons 


OF  THE  ABDOMINAL  CAVITY. 


471 


of  the  transversalis  abdominis  muscle,  and  of  the  linea  alba,  and  which 
terminate  near  the  umbilicus  by  a semicircular  edge. 

From  the  bladder  to  the  umbilicus  the  urachus  passes  over  its  in- 
ternal face,  on  the  sides  of  which  we  observe  the  remains  of  the  um- 
bilical arteries,  which  separate  below,  are  united  in  a single  cord  at 
their  upper  part,  penetrate  from  without  inward,  and  thus  produce  on 
the  inside  the  prominences  which  have  been  called  prolongations  of 
the  peritoneum  [processus  peritonei). 

On  the  inner  face  of  the  anterior  wall  we  remark  the  suspensory 
ligament  of  the  liver  (L.  hepatis  Suspensorium)  which  descends  from 
right  to  left  to  the  umbilicus.  It  is  a considerable  triangular  fold,  ex- 
panded like  a fan,  the  posterior  edge  of  which  is  attached  from  before 
backward  to  the  upper  face. of  the  liver,  where  it  separates  the  right 
from  the  left  lobe,  and  in  the  lower  and  loose  edge  of  which  we  distin- 
guish the  round  ligament  of  the  liver  (L.  hepatis  teres),  which  extends 
from  the  umbilicus  to  the  liver. 

B.  SUPEHIOB  WALL. 

§ 2538.  The  posterior  wall  covers  the  lower  face  of  the  diaphragm, 
to  which  it  is  loosely  attached. 

Near  the  posterior  edge  of  the  muscle  the  peritoneum  is  reflected  to 
the  right  on  the  liver,  and  not  only  covers  the  whole  of  this  viscus,  but 
also  when  it  comes  to  the  fissure  of  the  vena-portæ,  where  it  forms  as  it 
were  a sheath,  the  fasciculus  formed  by  the  union  of  the  hepatic  artery, 
the  vena-portæ  and  the  biliary  passages,  goes  on  the  upper  part  of  the 
duodenum,  to  be  continuous  there  with  the  small  epiploon,  the  great 
epiploon,  and  the  transverse  mesocolon. 

The  very  short  fold  between  the  blunt  edge  of  the  liver  and  the  up- 
per wall  of  the  peritoneum,  is  termed  the  coronary  ligament  of  the  liver 
(L.  hepatis  coronarium). 

From  the  right  side,  between  the  union  of  the  posterior  edge  of  the 
liver  with  the  anterior,  and  the  limit  of  the  posterior,  superior,  and  an- 
terior walls  of  the  peritoneum,  we  perceive  a larger  fold,  which  is  the 
right  triangular  ligament  of  the  liver  (L.  hepatis  trianguläre  dex- 
trum ). 

A similar  but  much  larger  fold  extends  from  the  posterior  edge  of 
the  small  lobe  of  the  liver,  and  from  its  summit,  to  the  posterior  wall  of 
the  peritoneum  ; it  is  the  left  triangular  ligament  of  the  liver  ( L.  he- 
patis trianguläre  sinistrum ),  which  is  continuous  forward  with  the  su- 
perior ligament  of  the  organ. 

In  the  place  where  the  esophagus  passes  through  the  peritoneum, 
in  proceeding  through  the  esophageal  fissure  of  the  ^diaphragm,  this 
membrane  covers  it  in  every  part,  and  also  in  the  upper  part  of  the 
stomach.  The  folds  which  result  from  them  are  termed  the  right  and 
left  phrenico- gastric  ligaments  (L.  phrenico-gastricum,  dextrum , and 
sinistrum).  The  first  is  continuous  with  the  small  epiploon,  and  the 


472 


DESCRIPTIVE  ANATOMY. 


second  with  the  suspensory  ligament  of  the  spleen  ( L . lienis  Suspen- 
sorium), which  is  situated  more  to  the  left,  between  the  upper  ex- 
tremity of  the  spleen  and  the  posterior  edge  of  the  upper  wall  of  the 
peritoneum. 


C.  POSTERIOR  WALL. 

§ 2539.  The  posterior  wall  descends  from  the  upper  and  posterior 
edge  of  the  liver,  from  the  cardiac  orifice  of  the  stomach,  from  the 
left  portion  of  the  small  curve  of  this  viscus,  and  from  the  upper  extre- 
mity of  the  spleen,  above  the  lumbar  portion  of  the  diaphragm,  then 
leaves  the  posterior  wall  of  the  abdominal  cavity,  and  goes  on  the  an- 
terior face  of  the  pancreas  and  duodenum,  to  which  organs  it  adheres 
very  slightly.  After  leaving  the  lower  edge  of  the  pancreas,  the  peri- 
toneum goes  downward  and  forward,  and  forms  the  upper  layer  of  the 
transverse  mesocolon,  a broad  and  considerable  fold,  which  receives 
anteriorly  the  transverse  colon  between  its  two  layers,  and  the  inferior 
layer  of  which  is  continuous  with  the  lower  part  of  the  posterior  layer. 

This  lower  part  descends  before  the  aorta,  the  vena-cava,  and  the 
kidneys,  to  which  organs  it  slightly  adheres,  and  afterwards  goes 
without  forming  any  fold,  on  the  right  or  left,  or  at  least  without  pro- 
ducing any  except  those  which  are  very  small,  on  the  ascending  and 
descending  portions  of  the  colon,  goes  also  to  the  right  side  of  the  kid- 
ney towards  the  duodenum,  the  anterior  face  of  which  it  covers,  inti- 
mately uniting  this  whole  intestine  with  the  upper  extremity  of  the  as- 
cending colon,  and  after  covering  all  these  parts,  is  continuous  with 
the  anterior  wall,  on  the  posterior  portion  of  the  transversalis  abdomi- 
nis muscle. 

Only  the  lower  part  of  the  descending  colon  and  the  commencement 
of  the  rectum,  form  a considerable  fold  on  the  central  part  of  the  psoas 
magnus  muscle,  and  on  the  upper  part  of  the  sacrum. 

Tn  the  centre  of  the  posterior  wall  is  a fourth  fold,  directed  obliquely 
from  left  to  right,  it  descends  from  the  second  lumbar  vertebra,  and  is 
termed  the  mesentery  (mesenterium) . This  fold,  the  root  of  which  is 
very  narrow,  enlarges  much  at  its  loose  edge,  which  embraces  all  the 
small  intestine  except  the  duodenum.  It  is  continuous  below  with  the 
right  mesocolon,  and  gives  off  a small  triangular  prolongation,  which 
serves  as  a mesentery  to  the  vermiform  appendage  of  the  cæcum. 

It  is  continuous  above  with  the  centre  of  the  transverse  colon. 

In  this  place  the  two  layers  of  these  folds  separate,  and  receive  be- 
tween them  the  lower  part  of  the  duodenum. 


OF  THE  ABDOMINAL  CAVITT. 


473 


D.  INFEBIOB  WALL. 

§ 2540.  We  may  consider  as  the  lower  wall  of  the  external  fold  of 
the  peritoneum,  the  part  of  this  membrane  which  corresponds  to  the 
pelvic  region  of  the  abdominal  cavity,  and  term  it  the  pelvic  portion. 

It  is  attached  very  loosely  to  the  iliaci  muscles,  to  the  lower  part  of 
the  abdominal  muscles,  to  the  levator  ani  muscle,  and  the  sacral 
plexus.  It  is  connected  forward  with  the  obturator  internus  muscle 
and  the  posterior  face  of  the  bladder.  It  covers  posteriorly  the  upper 
part  of  the  sacrum,  but  does  not  adhere  to  it  strongly,  and  is  reflected 
inward  on  the  upper  part  of  the  rectum. 

It  covers  below  in  the  two  sexes,  the  inner  part  of  the  levator  ani 
muscle,  to  which  it  is  loosely  united. 

The  anterior  and  posterior  halves  of  this  lower  wall  of  the  perito- 
neum, are  adapted  to  each  other,  between  the  bladder  and  the  rectum, 
so  that  in  the  male  the  anterior  passes  from  the  bladder  upon  the  semi- 
nal vesicles,  but  does  not  touch  them,  and  in  the  female,  from  the  blad- 
der upon  the  upper  part  of  the  vagina,  and  the  lower  part  of  the  uterus, 
which  it  loosely  envelops.  Having  thus  arrived  backward,  it  reunites 
to  the  posterior,  which  comes  from  the  rectum,  forming  a greater  or 
less  cul-de-sac  between  this  intestine  and  the  parts  we  have  mentioned. 

This  cul-de-sac  is  limited  on  the  right  and  left  by  two  longitudinal 
folds,  which  extend  in  the  male  from  the  rectum  to  the  lower  part  of 
the  bladder,  in  the  female  from  the  intestine  to  the  lower  part  of  the 
uterus,  and  are  termed  the  semilunar  folds  ( plieez  semilunares). 

These  folds  are  much  smaller,  and  consequently  the  cul-de-sac  is 
much  less  distinct  from  the  rest  of  the  peritoneal  cavity,  the  more 
the  rectum  and  the  bladder,  or  the  uterus  are  distended,  because  then 
the  peritoneum  is  enlarged  to  cover  its  parts. 

The  lateral  wall  of  the  pelvic  portion  of  the  peritoneum,  forms  in 
the  small  pelvis  of  the  female  a considerable  fold,  termed  the  broad 
ligament  of  the  uterus  (L.  uteri  latum).  This  fold  is  attached  to  the 
upper  part  of  the  vagina,  to  all  the  lateral  wall  of  the  uterus,  to  the 
Fallopian  tubes,  and  to  the  ovaries,  closely  covers  these  parts,  and 
lodges  between  its  two  folds  the  vessels  and  nerves  which  go  to  it. 

The  most  important  part  of  the  pelvic  portion  of  the  peritoneum,  is 
that  included  between  the  inner  extremity  of  the  iliac  crest  and  the 
sy mphy sis  pubis . ( 1 ) 

The  peritoneum  forms  in  this  place  two  depressions,  which  are  se- 
parated by  the  umbilical  ligament,  and  by  the  prolongation  of  the 


(1)  Hesselbach,  Ueber  den  Ursprung  der  Leistenbrüche,  Wurzburg',  1806. — Id., 
Ursprung  und  Fortschritte  der  Lcisten-und  Schekcnlbrüche,  Wurzburg,  1816. — Id., 
Disquisitioncs  anatomico-pathologicœ  de  ortu  et  progressu  herniarum  inguinalium 
et  cruralium,  Marburg,  1816. — K.  Liston,  Memoir  on  the  formation  and  the  connec- 
tions of  the  crural  arch  and  on  the  parts  contained  in  inguinal  and  crural  hernia, 
Edinburgh,  1819. 


474 


DESCRIPTIVE  ANATOMY. 


peritoneum  which  surrounds  it,  and  which  may  he  termed  the  inguinal 
fossæ  ; they  are  distinguished  into  external  and  superior , the  large, 
and  internal  or  inferior , the  smaller.  At  the  place  where  the  inguinal 
canal  commences,  we  usually  observe  in  the  peritoneum  a small  de- 
pression, which  is  often  connected  with  a cord  formed  of  cellular  tissue, 
which  passes  through  this  canal.  This  depression  frequently  forms  a 
greater  or  less  sac.  It  is  always  a remnant  of  the  prolongation  which 
formerly  extended  from  the  peritoneum  into  the  scrotum. 

The  external  inguinal  fossa  represents  a pyramid,  situated  between 
the  peritoneal  prolongation  and  the  commencement  of  the  inguinal 
canal.  The  internal  is  adapted  on  the  median  line  to  that  of  the  op- 
posite side,  from  which  it  is  always  more  or  less  completely  separated 
by  the  projection  of  the  urachus.  It  corresponds  directly  to  the  ingui- 
nal ring. 

B.  INTERNAL  FOLD  OF  THE  PERITONEUM. 

§ 2541.  The  internal  fold  of  the  peritoneum  which  covers  the  out- 
side of  the  parts  situated  in  the  cavity  of  the  abdomen,  is  much  thinner 
than  the  external.  It  is  not  arranged  exactly  in  the  same  manner  in 
regard  to  all  the  parts  it  covers,  for  it  is  attached  directly  to  some,  and 
to  others  only  by  more  or  less  considerable  prolongations.  In  several 
portions  it  extends  on  the  almost  loose  part  of  the  surface  of  the  or- 
gans, and  forms  prolongations,  which  are  sometimes  loose  and  float- 
ing, and  sometimes  contribute  also  to  unite  one  organ  with  another, 
independent  of  the  common  envelop. 

All  these  internal  prolongations  of  the  peritoneum,  whatever  be  their 
relation  with  the  organs,  are  formed  of  two  layers,  all  the  corrugated 
faces  of  which  adhere  to  each  other,  while  the  smooth  faces  are  loose 
and  turned  outward.  We  may  then  term  them  generally  the  folds  of 
the  peritoneum. 

The  folds  between  the  external  layer  of  the  peritoneum  and  the  in- 
testinal canal,  are  termed  the  mesenteries  (mesenteria).(  1) 

Those  which  are  shorter  but  broader,  and  which  exist  between  the 
external  fold  of  the  peritoneum  and  the  other  parts,  particularly  the 
stomach,  liver,  spleen,  &c.,  are  termed  the  ligaments  of  the  peritoneum 
( L.  peritonei).  Their  names  are  derived  sometimes  from  their  form, 
and  sometimes  from  the  parts  which  they  unite.  We  have  already 
mentioned  most  of  them,  in  describing  the  external  layer  : and  shall 
return  to  them  when  speaking  of  the  epiploon. 

The  folds  which  extend  from  one  viscus  to  another,  are  the  epiploa 
(omenta,  s.  epiploa) .(2) 

(1)  J.  S.  Henninger,  De  mesenterio,  Strasburg,  1714. — J.  Fantoni,  De  mesen- 
terio,  vasis  chylifcris  et  lymphaticis  ; in  the  Diss.  anat.  renov.  V. — Stock,  De  statu 
mesenterii  naturali  et  præternaturali,  Jena,  1755.— M.  Malpighi,  De  omento,  pin- 
guedine  et  adiposis  ductibus  ; in  Opp.  omn.,  vol.  i.  p.  227 

(2)  Henrici,  Diss.  sistens  novum  descriptionem  ct  iconem  omenti,  Copenhagen, 
1739  —Haller,  Omenti  nova  icon.;  in  the  Icon,  anat.fasc.  I,  and  opp.  min.,  vol.  i.— 


OF  THE  ABDOMINAL  CAVITY. 


475 


Those  which  only  project  on  the  surface  of  a viscus,  are  termed  the 
epiploic  appendages  ( appendices  epiploicœ). 

The  last  two  lands  of  folds  differ  from  all  others,  as  they  are  ex- 
tremely thin,  so  that  many  anatomists  have  even  considered  their  reti- 
culated or  perforated  structure  as  a normal  arrangement. 

A.  MESENTEBIES. 

§ 2542.  The  best  mode  is  to  commence  the  history  of  the  folds  of 
the  peritoneum  by  that  of  the  mesenteries. 

a.  Mesentery. 

§ 2543.  The  proper  mesentery  ( meseiiterium ) is  directed  obliquely 
from  above  downward,  and  from  right  to  left  ; it  extends  from  the  left 
side  of  the  body  of  the  second  lumbar  vertebra,  to  the  right  sacro-iliac 
symphysis. 

It  is  composed  of  two  layers,  a right  and  a left,  which  are  separated 
in  the  upper  two  thuds  of  the  mesentery,  by  the  third  or  the  ascending 
portion  of  the  duodenum,  but  which  unite  beyond  this  portion,  and  in 
the  lower  third  of  the  mesentery. 

The  posterior  edge,  which  rests  on  the  vertebral  column,  is  termed 
the  root  of  the  mesentery  ( radix  mesenterii).  It  is  much  shorter  than 
the  anterior,  by  which  it  is  attached  to  the  small  intestine,  so  that  its 
layers  separate  on  arriving  at  the  intestine,  which  they  receive  be- 
tween them,  and  narrowly  embrace  them  in  all  their  extent. 

The  mesentery  enlarges  imperceptibly  from  its  upper  and  lower 
parts,  to  its  centre.  Its  greatest  breadth  is  about  four  inches. 

Between  the  two  layers  which  compose  it,  and  which  are  easily  se- 
parated, are  cellular  tissue,  fat,  lymphatic  ganglions,  blood-vessels, 
lymphatic  and  chyliferous  vessels,  and  nerves. 

It  is  continuous  at  its  upper  extremity  with  the  transverse  meso- 
colon, at  the  lower,  with  the  triangular  mesentery  of  the  vermiform 
appendix  of  the  cæcum,  which  is  attached  to  the  left  side  of  its  circum- 
ference, and  the  left  side  of  which  is  perfectly  loose,  and  continuous 
with  the  ascending  mesocolon. 

b.  Mesocolon. 

§ 2544.  The  colon  is  not,  like  the  small  intestine,  attached  to  the 
posterior  wall  of  the  abdominal  cavity  by  a very  long  fold,  which  per- 


Reebmann,  De  omento  sano  et  morboso,  Strasburg-,  1753. — P.  Yan  Nœmer,  De  fa 
hrica  et  usu  omenti,  Leyden,  1764. — Chaussier,  Essai  sur  la  structure  et  les  usages  - 
des  épiploons  ; in  the  Mém.  deVac.de  Dijon,  1784. — Froriep,  Neue  Darstellung  der 
Gehroses  und  der  Netze,  Weimar,  1812. 


476 


DESCRIPTIVE  ANATOMY. 


mits  it  to  float  freely.  On  the  contrary,  it  is  atttached  more  firmly  and 
immovably  by  the  mesocolon. 

After  covering  the  centre  of  the  duodenum  on  the  right  side,  the 
posterior  wall  of  the  peritoneum  goes  on  the  ascending  portion  of  the 
colon,  and  covers  it  anteriorly,  but  not  posteriorly,  or  at  least  but  very 
rarely,  where  it  is  exposed  on  the  anterior  face  of  the  kidney.  Even 
when  the  ascending  colon  is  entirely  enveloped  by  the  peritoneum,  the 
fold  which  attaches  it  is  always  very  short. 

The  cæcum  is  most  generally  attached  rather  more  loosely  to  the 
upper  part  of  the  iliacus  muscle. 

There  are  often  detached  from  its  summit  two  triangular  folds,  di- 
rected from  right  to  left,  and  from  above  downward,  which  leave  be- 
tween them  a depression,  the  base  of  which  is  formed  by  the  iliacus 
muscle  and  the  cæcum,  and  into  which,  particularly  when  the  cavity 
is  considerable,  a greater  or  less  portion  of  the  intestine  enters  and  is 
strangulated. 

The  transverse  mesocolon  ( mesocolon  transverswn ),  which  is  unin- 
terruptedly continuous  with  the  ascending  mesocolon,  is  an  elongated 
quadrilateral  fold,  about  four  inches  high,  which  extends  from  right  to 
left  near  the  centre  of  the  abdominal  cavity,  and  which  is  much  higher 
in  the  centre'  than  on  the  sides. 

It  arises  on  the  right  from  the  centre  of  the  duodenum,  in  the  centre 
from  the  anterior  face  of  the  pancreas,  often  also  from  the  right  side  of 
the  posterior  face  of  the  stomach,  farther,  and  towards  the  left,  from 
the  extremity  of  the  duodenum,  and  is  attached  to  the  transverse  colon 
by  its  anterior  edge. 

At  its  commencement  on  the  right  on  the  duodenum,  it  is  continu- 
ous above  and  below  with  the  portion  of  the  posterior  wall  of  the  peri- 
toneum, which  covers  the  duodenum  anteriorly,  and  intimately  unites 
this  intestine  to  the  colon. 

Farther  on  the  right,  its  upper  layer  closely  unites  with  a greater  or 
less  portion  of  the  great  epiploon,  so  that  hence,  a quadruple  layer 
from  the  duodenum  to  a greater  or  less  portion  of  the  right  half  of  the 
great  curve  of  the  stomach  exists,  and  this  union  of  the  right  edges  of 
the  great  epiploon  and  transverse  mesocolon,  always  closes  in  this 
place  the  sac  formed  by  these  two  folds. 

It  imperfectly  divides  the  internal  fold  of  the  peritoneum  into  two 
halves,  a superior,  smaller,  and  an  inferior,  which  is  larger. 

The  descending  mesocolon,  the  direct  continuation  of  the  preceding, 
is  quadrilateral  at  its  upper  part,  and  does  not  generally  surround  the 
whole  circumference  of  the  descending  colon.  It  arises  from  the  upper 
part  of  the  anterior  face  of  the  left  kidney,  but  comes  also  in  its  centre, 
where  it  is  more  extensive,  from  the  anterior  fold  of  the  posterior  tendon 
of  the  transversalis  abdominis  muscle,  finally  below  where  it  is  larger 
than  in  any  other  part,  and  often  also  as  broad  as  the  transverse  me- 
socolon, from  the  left  psoas  muscle  and  the  sacro-iliac  symphysis  of 
the  same  side. 


OF  THE  ABDOMINAL  CAVITV. 


477 


A small  part  of  the  upper  portion  of  the  rectum  is  attached  to  the 
anterior  face  of  the  sacrum  by  a short  fold  of  the  peritoneum,  termed 
the  mesorectum. 


B.  EPIPLOA. 

a.  Great  epiploon. 

§ 2545.  The  great  epiploon,  epiploon  gastro-colique,  descends  by 
its  upper  edge  : 

1 st.  From  the  lower  part  of  the  fissure  of  the  spleen,  and  from  its 
lower  extremity,  where  it  is  united  with  the  gastro-splenic  ligament. 

2d.  From  all  the  great  curve  of  the  stomach. 

3d.  From  the  commencement  of  the  duodenum. 

It  is  adapted  to  the  anterior  part  of  the  circumference  of  the  trans- 
verse colon,  goes  before  the  small  intestine,  and  generally  descends 
into  the  pelvis,  where  it  terminates  by  a loose  edge. 

Its  straight  edge  unites  with  the  transverse  mesocolon,  and  is  at- 
tached by  the  left  to  the  lower  extremity  of  the  spleen,  and  also  to  the 
left  extremity  of  the  pancreas  and  the  transverse  colon,  uniting  with 
the  posterior  wall  of  the  peritoneum. 

• b.  Small  epiploon. 

§ 2546.  The  small  epiploon,  epiploon  gastro-hepatique  ( epiploon  he- 
patico-gastricum),  descends  from  the  fissure  of  the  venous  canal,  from 
the  left  portion  of  the  fissure  of  the  vena-portæ,  and  the  capsule  of  Glis- 
son, towards  the  small  curve  of  the  stomach,  from  the  cardiac  to  the 
pyloric  orifice,  and  floats  before  the  lobe  of  Spigel. 

The  two  epiploa  communicate  by  the  portion  of  the  peritoneum 
which  covers  the  anterior  and  posterior  faces  of  the  stomach,  and  thus 
forms,  with  the  stomach,  the  anterior  wall  of  a sac,  the  lower  wall  of 
which  is  constituted  by  the  transverse  colon  and  the  transverse  meso- 
colon, and  the  posterior  by  the  upper  part  of  the  posterior  wall  of  the 
peritoneum. 

The  upper  part  of  this  sac,  which  is  placed  between  the  liver  and 
the  small  curve  of  the  stomach,  communicates  with  the  inferior,  situa- 
ted between  the  small  curve  and  the  transverse  colon,  by  a greater  or 
less  opening,  which  is  found  between  the  posterior  wall  of  the  stomach 
and  that  of  the  peritoneum,  in  the  part  where  the  small  curve  of  the 
stomach,  near  its  right  extremity,  is  not  attached  to  the  posterior  wall 
of  the  peritoneal  sac. 

The  whole  sac  or  the  cavity  of  the  epiploon  communicates  with  the 
peritoneal  cavity  by  the  foramen  of  Winslow  ( foramen  Winslowii),  a 
rounded,  oblong  opening,  situated  on  the  right  side  of  the  abdomen, 
bounded  on  the  right  by  the  fissure  of  the  vena-portæ,  forward  by  the 
Vol.  III.  61 


476 


DESCRIPTIVE  ANATOMY. 


fasciculus  formed  by  the  vena-portæ,  the  hepatic  artery,  and  the  biliary 
passages,  on  the  left  by  the  first  curve  of  the  duodenum,  and  below  by 
the  posterior  wall  of  the  peritoneum,  which  the  ascending  vena-cava 
covers  in  this  place. 

When  we  separate  the  liver  and  duodenum,  and  consequently  re- 
move from  this  latter  organ  the  portion  of  peritoneum  which  extends 
from  its  summit  to  the  liver,  in  forming  a sheath  around  the  fasciculus 
we  have  mentioned,  a more  or  less  broad,  semicircular  fold  is  formed, 
having  its  loose  edge  turned  downward  ; this  is  termed  the  hepato- 
duodenal ligament  ( L . hepato-duodenale). 

We  may  produce  also  in  the  same  manner  an  analogous  fold  be- 
tween the  first  curve  of  the  duodenum  and  the  upper  extremity  of  the 
right  kidney.  This  last  fold  is  the  duodcno-renal  ligament  {L.  duo- 
deno-renale). 

The  foramen  of  Winslow  is  situated  between  these  two  folds. 


c.  Epiploic  appendages. 

§ 2547.  The  epiploic  appendages  ( Appendices  epiploicœ)  are  short 
prolongations  of  the  peritoneal  tunic  of  the  large  intestine  ; they  are 
rounded,  oblong,  varying  in  breadth,  filled  with  fat  in  fleshy  people, 
and  with  a reddish,  gelatinous  liquid  in  lean  persons.  They  arise 
principally  from  the  anterior  side  of  the  edge  of  thjs  tunic. 

They  are  observed  along  the  whole  length  of  the  colon,  but  they 
are  not  arranged  exactly  in  the  same  manner  in  all  parts  of  this  in- 
testine. 

They  always  receive  a considerable  vascular  branch,  which  comes 
from  the  mesocolon. 

They  are  generally  arranged  in  two  rows. 

These  rows  are  situated  on  the  outside  and  the  inside  of  the  intes- 
tine in  the  lower  portion  of  the  descending  colon,  on  the  lower  edge  in 
the  transverse  colon,  finally  on  the  internal  and  anterior  edge  in  the 
descending  colon. 

In  this  latter  point  one  of  the  two  rows,  the  longest,  is  much  nearer 
the  intestinal  extremity  of  the  mesocolon  than  in  the  ascending  colon. 

In  the  ascending  colon,  the  epiploic  appendages  receive  the  external 
and  internal  branches  of  the  mesenteric  vessels.  In  the  rest  of  the 
colon  their  vessels  come  only  from  the  lower  and  internal  branches  of 
those  of  the  intestine. 

The  mesocola  form  also  at  intervals  near  the  intestine  similar  pro- 
longations, which  are  directed  from  above  downward. 


OP  THE  ABDOMINAL  CAVITY. 


479 


B.  PERIODICAL  DIFFERENCES. 


I.  REGULAR  AND  GENERAL  DIFFERENCES. 

§ 2548.  1st.  The  abdominal  cavity  is  much  larger  in  proportion  to 
the  chest,  during  the  early  periods  of  existence,  than  when  the  subject 
is  fully  grown,  but  its  pelvic  portion  is  infinitely  smaller. 

2d.  Until  the  third  month  of  pregnancy  it  extends  by  means  of  a 
prolongation,  the  length  and  the  breadth  of  which  are  in  direct  ratio 
with  the  youthful  age  of  the  new  being,  and  which  incloses  a portion 
of  the  intestinal  canal,  with  the  umbilical  and  omphalo-mesenteric  ves- 
sels, in  the  umbilical  sheath  formed  by  the  inner  membrane  of  the  ovum, 
so  that  this  sheath  then  really  makes  part  of  it.  The  anterior  cavity  is 
covered  by  a prolongation  which  is  also  reflected  on  the  viscera  which 
it  contains. 

In  the  fetus  of  three  months,  the  anterior  wall  of  the  peritoneum 
extends  already  on  the  opening  of  the  umbilicus,  through  which  the 
umbilical  vessels  enter  and  depart,  but  does  not  give  off  in  this  place 
a prolongation  which  penetrates  into  the  cord. 

We  do  not  perceive  at  first  any  well  marked  difference  between  the 
general  ligaments  and  the  umbilical  sheath  ; but  this  difference  is  seen 
in  proportion  as  the  development  of  the  skin  progresses.  Hence  in  the 
full-grown  fetus  the  root  of  the  umbilical  cord  is  surrounded  by  a cylin- 
drical fold  of  skin,  which  is  about  four  lines  long,  and  is  usually  more 
distinct  from  the  umbilical  sheath  on  the  right  side  than  the  left,(l) 
the  inner  face  of  which  is  strengthened  by  some  fibres  of  the  linea- 
alba. 

The  umbilical  ring  is  much  broader  the  younger  the  fetus  is.  It 
gradually  contracts,  and  in  the  full-grown  fetus  it  exactly  surrounds 
the  umbilical  vessels.  Its  lower  part  particularly  is  intimately  united 
with  the  umbilical  artery  by  a short  and  firm  cellular  tissue  ; the  cel- 
lular tissue  which  unites  the  upper  with  the  umbilical  vein  is  looser. 
The  umbilical  ring  is  already  surrounded  in  the  full-grown  fetus  with 
very  strong  and  perfectly  developed  tendinous  fibres,  while  the  linea 
alba,  less  advanced  in  all  these  respects,  is  formed  only  of  indistinct 
and  proportionally  shorter  and  narrower  tendinous  fibres. 

After  birth  the  portion  of  the  cord  left  on  the  body  of  the  infant  dies 
in  its  whole  extent  where  it  is  covered  by  the  umbilical  sheath.  In- 
stead of  the  cylindrical  fold  of  skin,  there  forms  a depressed  cicatrix, 
the  navel  or  umbilicus , the  depression  of  which  depends  principally  on 
the  disappearance  at  this  period  of  the  prominence  previously  formed 
by  the  umbilical  vessels  and  the  gelatine  of  Wharton. 


(1)  Scemmerring,  Ucbcr  Nabelbrüche,  Frankfort,  1811,  p.  7. 


480 


DESCRIPTIVE  ANATOMY. 


It  depends  also  on  the  general  law  that  the  cicatrices  of  the  skin 
are  attended  with  a greater  or  less  contraction.  The  collapsing  of  the 
umbilical  vessels  also  assists  to  form  it.  Afterward  the  depression 
increases  as  much  more  as  there  is  fat  deposited  in  the  surrounding 
parts,  for  this  fluid  never  accumulates  in  the  cicatrix. 

The  umbilical  ring  and  the  peritoneum  gradually  adhere  very  inti- 
mately with  the  cellular  tissue  and  the  skin  which  covers  them.  In 
the  book  on  embryology  we  shall  mention  the  changes  in  the  umbi- 
lical vessels. 

3d.  In  the  male  and  female  fetus,  the  peritoneum  forms  another  cul- 
de-sac,  the  diverticulum  of  JYuck  ( diverticulum  Nuckii),  which  extends 
through  the  inguinal  canal  and  inguinal  ring.  This  diverticulum  is 
connected  with  the  development  of  the  testicle  in  the  male.  It  has 
even  the  same  use  in  the  female,  but  as  it  here  receives  no  organ  it  is 
much  narrower  and  shorter,  and  often  disappears  before  the  end  of  the 
last  month  of  pregnancy. 

The  great  epiploon  appears  in  the  second  month  of  pregnancy. 
Until  the  fourth  there  exists  only  a simple  prolongation  of  the  peri- 
toneal coat  of  the  stomach,  which  is  not  yet  connected  with  the  trans- 
verse colon. 

The  epiploic  appendages  of  the  large  intestine  appear  at  the  fifth 
month  of  pregnancy. 

II.  ACCIDENTAL  DIFFERENCES. 

§ 2549.  The  abdominal  cavity  is  considerably  distended  during 
pregnancy  : but  it  returns  almost  entirely  to  its  normal  dimensions 
after  parturition.  We  have  not  observed  any  marked  difference  either 
in  the  region  of  the  umbilicus  or  in  other  parts,  even  in  those  females 
who  have  had  several  children,  nor  has  Sœmmerring.(l)  But  the 
skin  being  much  less  extensible,  wrinkles  are  formed  in  the  general 
integuments  of  the  abdomen  by  pregnancy,  which  are  not  seen  in  fe- 
males who  have  had  no  children. 


C.  DIFFERENCES  RELATIVE  TO  SEX. 

§ 2550.  The  abdominal  cavity  is  smaller  in  proportion  to  the  chest 
in  the  male  than  in  the  female,  in  whom  it  is  much  longer  and  nar- 
rower at  its  upper  part,  but  much  broader  in  the  lower,  that  is,  in  its 
pelvic  portion.  The  hairs  of  the  pubis  also  differ  in  their  arrangement. 
In  fact  in  females  they  suddenly  cease,  and  occupy  only  the  centre  of 
the  space  between  the  umbilicus  and  the  symphysis  pubis,  while  in 
the  male  they  extend  in  a point  to  the  umbilicus. 


(1)  Loc.  cit.,  p.  25. 


OF  THE  ABDOMINAL  CAVITY. 


481 


ARTICLE  SECOND. 

OF  THE  ABDOMINAL  CAVITY  IN  THE  ABNORMAL  STATE. 

A.  DEVIATIONS  OF  FORMATION. 

§ 2551.  1st.  When  the  upper  half  of  the  body  is  not  perfectly  de- 
veloped, in  acephalia  vera,  the  abdominal  cavity  presents  more  or  less 
the  same  deviation  of  formation  at  its  summit,  so  that  sometimes  only 
the  pelvic  portion  exists,  and  this  also  is  frequently  narrower  than  in 
the  normal  state. 

In  other  cases,  on  the  contrary,  tumors,  congestions,  liquids,  &c., 
often  distend  it  very  much. 

2d.  Curvature  of  the  spine,  which  sometimes,  but  very  rarely,  con- 
stitutes a primitive  deviation  of  formation,  naturally  causes  a greater 
or  less  alteration  in  the  form  of  the  abdominal  cavity  and  the  situation 
of  the  parts  within  it. 

3d.  This  cavity  not  unfrequently  presents  anomalies  depending  on 
the  permanence  of  one  of  the  degrees  of  formation  through  which  it 
successively  passes,  that  is,  the  openings  and  prolongations  first  exist- 
ing at  its  upper  or  lower  extremity  do  not  disappear  in  a greater  or 
less  portion  of  their  extent.  This  causes  congenital  umbilical  hernia, 
and  the  abnormal  communication  between  the  vaginal  tunic  of  the 
testicle  and  the  cavity  of  the  peritoneum,  which  give  rise  to  congenital 
inguinal  hernia. 

Frequently  also  the  connections  of  the  abdominal  parietes  with  the 
parts  contained  in  this  cavity,  particularly  those  of  the  external  and 
internal  layers  of  the  peritoneum,  are  abnormal. 

This  abnormal  state  is  sometimes,  but  rarely,  the  effect  of  a primi- 
tive deviation  of  formation.  It  is  generally  consecutive. 

It  is  much  more  common  to  observe  unusual  connections,  adhesions, 
which  are  generally  the  consequence  of  an  inflammation  of  the  peri- 
toneum, and  which  are  caused  by  effusion.  Sometimes  even  in  this 
case  all  the  organs  surrounded  by  the  peritoneum  are  so  blended  in 
one  mass  that  they  cannot  be  perfectly  separated  ; but  they  generally 
adhere  only  in  some  parts. 

Solutions  of  continuity  are  very  rare,  and  generally  constitute  primi- 
tive deviations  of  formation. 

If  the  adhesions  occur  so  that  they  produce  a kind  of  bridge  between 
the  two  parts,  this  arrangement  may  induce  in  the  cavity  of  the  abdo- 
men the  same  consequences  as  certain  solutions  of  continuity,  as  an 
opening  also  results  from  them  ; but  this  is  a subject  naturally  con- 
nected with  that  of  internal  hernias,  of  which  we  shall  speak  here- 
after. 


482 


DESCRIPTIVE  ANATOMY. 


4th.  The  abdominal  viscera  are  not  unfrequently  displaced.  Most 
of  these  displacements  are  termed  hernias, ( 1)  which  term  includes 
every  abnormal  situation  of  a viscus  which  leaves  the  cavity  in 
which  it  is  normally  situated,  or  which  enters  into  a generally  abnor- 
mal compartment  of  the  cavity  in  which  it  is  situated. 

The  first  case  constitutes  the  external , and  the  second  the  internal 
hernias. 


I.  EXTERNAL  HERNIAS. 


§ 2552.  The  most  important  points  in  the  history  of  hernia  are, 
the  relations  of  the  displaced  parts  with  the  integuments,  the  na- 
ture of  the  herniary  parts  and  the  changes  in  them,  finally  the  place 
where  the  hernia  occurs,  and  the  peculiar  phenomena  presented  by 
each  species  of  hernia  in  the  first  two  respects. 

1st.  JYature  of  the  envelops.  Beside  the  integrity  of  the  common 
integuments,  which  occurs  first  in  most  hernias,  the  most  general  con- 
dition of  this  anomaly  is  the  existence  of  a herniary  sac,  produced  by 
the  elongation  of  the  peritoneum. 

The  internal  hernias  differ  in  this  respect  from  the  external  : for  the 
parts  which  have  passed  through  an  abnormal  opening  in  the  cavity 
of  the  abdomen  are  not  surrounded  with  a herniary  sac.  Besides 
sometimes  we  find  no  sac  in  the  external  hernias,  whither  it  has  never 
existed,  as  when  the  peritoneum  is  torn,  or  it  has  been  destroyed  by 
compression,  suppuration,  gangrene. 

The  herniary  sac  is  principally  deficient  in  phrenic  hernia,  from  a 
rupture  of  the  peritoneum. 

On  the  other  hand  the  peritoneum  and  thè  cellular  tissue  which 
surrounds  it  externally  gradually  thicken  and  become  harder  to  some 
extent,  particularly  at  the  entrance  or  neck  of  the  herniary  sac,  which 
happens  particularly  after  long  compression. 

Not  unfrequently  also  inflammations  arise  from  the  prolongations 
which  extend  from  one  point  of  the  circumference  of  the  herniary  sac 
to  the  others. 


(1)  J.  G.  Gunz,  Observationum  anatomico-chirurgicarum  de  herniis  libellas , Leip- 
sic,  1744. — G.  Vogel,  Abhandlung  aller  Arten  der  Brüche,  Leipsic,  1756. — P.  Pott, 
'l'reatise  on  ruptures,  London,  1756. — J.  T.  Klinkosch,  Programma  quo  divisioncm 
herniarum  novamque  herniae  ventralis  speciem  proponit , Prague,  1764. — Arnaud, 
Mémoires  de  chirurgie,  London,  1768,  vol.  ii. — A.  T.  Richter,  Abhandlung  von  den 
Brüchen,  Leipsic,  1778. — Monteggia,  Qucedam  de  hernis  ; in  the  Fase.  anat.  path., 
1793. — J.  and  C.  Wenzel,  Eilf  Beobacktungenueber  Brüche  ; in  Loder,  Journal  für 
Chirurgie,  vol.  iii.  pt.  ii.  1800,  p.  217-258. — A.  Monro,  The  morbid  anatomy  of  the 
human  gullet,  p.  363-542.— J.  F.  Meckel,  Handbuch  der  pathologischen  Anatomie, 
vol.  ii.  pl.  i.  p.  358-484. — A.  Scarpa,  Traité  pratique  des  hernies,  Paris,  1812-1823. — 
Lawrence,  Traité  des  hernies,  Paris,  1818.  J.  CÎoquet,  Recherches  anatomiques  sur 
les  hernies  de  l’abdomen,  Paris,  1817-1819. — Breschet,  Essai  sur  la  hernie  fémorale, 
Pari3, 1819. 


OF  THE  ABDOMINAL  CAVITY, 


483 


2d.  Nature  of  the  abdominal  organs  which  form  the  hernia.  We 
must  consider  here  the  quality  of  the  organs,  then-  state,  and  their  rela- 
tions with  the  herniary  sac. 

a.  Hernia  is  most  generally  formed  by  a portion  of  the  small  intes- 
tine or  of  the  epiploon,  more  rarely  by  a portion  of  the  large  intestine, 
still  more  rarely  by  the  liver  or  a portion  of  the  urinary  or  genital 
organs.  We  however  possess  several  instances  of  hernia  of  the 
uterus,  the  ovaries,  the  Fallopian  tubes,  and  the  bladder.  An  intes- 
tinal hernia  usually  includes  all  the  circumference  of  the  intestine. 
We  rarely  find  in  it  only  a portion  of  the  surface  of  the  organ. 

b.  The  herniary  parts  are  abnormal,  either  in  respect  to  their  situa- 
tion only,  or  also  in  their  functions  and  texture.  This  latter  case  hap- 
pens particularly  when,  from  a want  of  proportion  between  the  capa- 
city of  the  herniary  sac  and  the  volume  of  the  part  displaced,  this 
latter  is  compressed,  strangulated,  whence  it  inflames,  and  even  be- 
comes gangrenous  when  the  disproportion  continues.  If  gangrene 
occurs,  the  herniary  portion  is  separated  from  that  which  is  contained 
in  the  abdominal  cavity,  which  causes,  when  hernia  of  the  intestine 
exists,  the  formation  of  an  abnormal  opening  termed  an  artificial  anus. 
Some  and  even  large  portions  of  the  intestinal  canal  may  be  destroyed, 
although  no  feces  escape  into  the  abdomen,  and  without  the  close  of 
the  natural  opening.  This  close  in  fact  occurs  sometimes  from  the 
effusion  of  fibrin  all  around  the  opening  produced  by  the  gangrene, 
which  is  obliterated  at  first  on  the  side  of  the  cavity  of  the  intestine, 
then  externally.  It  occurs  even  in  some  cases  where  there  was  not 
the  least  direct  communication  between  the  upper  and  lower  ends  of 
the  intestine. 

c.  The  herniary  parts  do  not  generally  adhere  at  first  to  the  herni- 
ary sac,  excepting  their  envelops,  as  when,  for  instance,  in  the  hernias 
of  the  ascending  or  descending  colon,  the  displaced  part  is  primitively 
united  to  the  sac  : but  afterward,  exsudation  which  succeeds  inflam- 
mations of  the  serous  membranes  so  rapidly,  causes.the  serous  mem- 
brane of  the  herniary  sac  to  adhere  more  or  less  intimately  with  the 
displaaed  viscus.  The  hernia  is  then  said  to  be  adherent. 

3d.  Certain  regions  of  the  abdomen  are  more  subject  to  hernias  than 
others  ; particularly  those  which  have  a sloping  situation,  and  which 
on  account  of  their  structure,  are  but  slightly  resisting.  The  most 
common  hernias  are  bubonocele  and  merocele,  which  take  place,  one 
through  the  inguinal  ring,  the  other  through  the  crural  arch.  The 
inguinal  hernias  become  scrotal  when  these  viscera  descend  into  the 
scrotum.  The  bubonocele  is  more  common  in  males,  and  the  merocele 
in  females.  Next  come  the  umbilical  hernias,  then  the  ventral , next 
those  through  the  foramen  ovale , then  the  phrenic , and  lastly  the 
ischiatic  and  the  lumbar. 

a.  In  inguinal  hernia,  the  viscera  always  emerge  through  the  in- 
guinal ring,  but  do  not  always  come  there  in  the  same  manner.  In 
the  external  or  oblique  inguinal  hernia,  which  is  infinitely  more  com- 
mon than  the  other,  the  viscera  emerge  through  the  inguinal  anal,  so 


484 


DESCRIPTIVE  ANATOMY. 


that  the  tumor  has  at  first  an  oblique  direction  ; on  the  contrary,  in  the 
internal  or  right  inguinal  hernia,  it  proceeds  directly  from  above  down- 
ward, towards  the  ring  on  the  inside  of  the  old  umbilical  artery,  and 
passes  through  or  distends  the  lower  part  of  the  broad  internal  abdomi- 
nal muscles  which  are  situated  before  it.  Hence  the  differences  be- 
tween these  two  hernias,  in  respect  to  their  envelops  and  the  relations 
of  the  tumor  with  the  adjacent  parts. 

The  external  inguinal  hernia  is  inclosed  in  all  the  envelops  of  the 
spermatic  cord,  consequently,  in  the  cremaster  muscle  and  the  com- 
mon vaginal  tunic.  The  spermatic  cord  is  situated  behind  the  tumor, 
and  follows  the  same  direction.  The  epigastric  artery  is  reflected  from 
without  inward,  and  from  below  upward,  behind  this  tumor.  The  form 
of  the  hernia  is  oblong,  at  least  at  first. 

The  internal  inguinal  hernia  is  not  generally  enveloped  by  the  cre- 
master muscle  and  the  vaginal  tunic,  but  only  by  the  cellular  tissue  of 
the  scrotum.  It  is  situated  on  the  inside  of  the  cord,  does  not  pass  be- 
fore it,  and  sometimes  is  found  behind  it.  The  epigastric  artery  as- 
cends at  its  inner  side,  and  its  form  is  rounder. 

Although  these  differences  occur  generally,  the  rule  is  however  sub- 
ject to  exceptions.  Thus  in  one  case,  the  cremaster  muscle  evidently 
passed  on  the  anterior  face  of  an  internal  inguinal  hernia. (1)  In  ano- 
ther case,  the  spermatic  cord  proceeded  transversely  on  the  neck  of  an 
internal  hernia,  towards  its  inner  side,  and  farther,  near  its  posterior 
side.(2)  Finally,  in  a third,  the  epigastric  artery  ascended  to  the  in- 
side of  the  tumor. (3) 

Congenital  hernia  is  a variety  of  external  inguinal  hernia,  in  which 
the  viscera  descend  in  the  unobliterated  prolongation  of  the  peritoneum, 
and  are  consequently  situated  in  the  same  cavity  as  the  testicle,  which 
even  sometimes  adheres  to  them  before  leaving.  We  must  also  com- 
pare with  external  inguinal  hernia,  that  recently  described  as  the  in- 
fantile hernia,  where  the  displaced  viscera  are  engaged  in  the  vaginal 
tube.  This  hernia  may  present  two  forms.  Sometimes,  in  fact,  the 
vaginal  tube  is  open  its  whole  extent,  both  on  the  side  of  the  testicle 
and  that  of  the  abdomen,  and  sometimes  only  on  one  side.  In  the  first 
case  the  herniary  sac  does  not  touch  the  testicle,  as  does  the  organ  dis- 
placed in  congenital  hernia.  In  the  second,  when  the  vaginal  tube  is 
open  at  its  upper  part,  the  hernia  is  enveloped  by  a second  sac,  which 
forms  it,  exactly  as  in  any  hernia,  the  part  contained  in  the  sac  is  by 
this  sac.  When,  on  the  contrary,  the  tube  is  closed  above,  the  sac 
occupies  also  the  upper  part  of  the  vaginal  tunic,  but  in  a still  more 
complex,  since  this  tunic  sends  to  it  two  envelops,  an  external  and  an 
internal. 

The  external  is  arranged  as  in  the  second  case,  and  the  relations  of 
the  vaginal  tube  are  not  changed.  The  internal,  on  the  contrary,  is 

(1)  Todd,  On  hernia  ; in  the  Dublin  hospital  reports.  Dublin,  1817,  vol.  i.  p.  231. 

(2)  Ibid. 

(3)  Hesselbach,  Leisten-und  Schenkelbruche , Wurzburg,  1815,  p.  45. 


OF  THE  ABDOMINAL  CAVITY. 


485 


pushed  back  at  its  upper  part,  and  reversed  by  the  hernia,  whence  in 
this  case  the  sac  is  smooth  externally.  We  conceive  that  in  ail  these 
cases  the  number  of  the  envelops  of  the  hernia  is  augmented,  and  that 
it  is  really  provided  with  a double  sac.  In  the  first  it  may  be  com- 
plicated with  a common  congenital  hernia;  in  the  second  also,  two  her- 
nias may  coexist. (1) 

Inguinal  hernia  is  much  more  common  in  the  male  than  in  the  fe- 
male, because  the  inguinal  ring  is  broader  in  the  male,  and  the  va- 
ginal prolongation  remains  open  much  longer  in  him. 

b.  Crural  hernia  takes  place  below  the  crural  arch.  It  is  rounded, 
and  is  generally  situated  on  the  inner  side  of  the  crural  vessels,  before 
the  epigastric  artery,  usually  also  before  the  obturator  artery,  even 
when  the  latter  comes  from  the  epigastric  artery,  sometimes,  however, 
behind  it.  Its  neck  is  situated  in  the  male  directly  below  the  upper 
part  of  the  spermatic  cord  ; in  the  female  below  the  lower  part  of  the 
round  ligament  of  the  uterus.  It  is  more  common  in  the  female  than 
in  the  male,  on  account  of  the  greater  distance  between  the  symphysis 
pubis  and  the  anterior  extremity  of  the  iliac  crest. 

c.  Umbilical  hernia  occurs  either  through  the  umbilical  ring,  or  in 
its  neighbourhood,  through  a fissure  in  the  linea  alba.  The  first  case 
is  the  most  common  when  the  tumor  exists  as  soon  as  the  child  come3 
into  the  world,  and  depends  on  suspended  development.  The  second 
is  still  more  so  when  the  hernia  is  formed  there  accidentally.  It  fre- 
quently has  a rounded  form,  and  is  rarely  oblong. 

d.  Ventral  hernias  are  observed  principally  in  the  epigastric  and  the 
inguinal  region,  around  the  ring. 

e.  Ovular  hernia(2)  occurs  through  the  space  at  the  upper  and 
outer  part  of  the  foramen  ovale.  It  is  then  situated  very  deeply  before 
the  obturator  vessels  and  nerves,  below  and  behind  the  adductor 
muscles  of  the  thigh. 

f Phrenic  hernia(3)  supervenes  in  very  different  parts  of  the  dia- 
phragm, and  it  is  destitute  of  a sac  more  frequently  than  any  other 
hernia.  It  is  congenital  much  more  frequently  than  accidental,  which 
undoubtedly  depends  on  the  necessity  of  extreme  violence  to  produce 
it,  for  since  when  it  occurs  the  viscera  are  displaced  in  a direction 
opposite  to  their  weight. 

g.  and  h.  Hernias  through  the  sciatic  notch  and  the  lumbar  region, 
are  extremely  rare.  The  second  has  no  peritoneal  envelop,  and  is 
generally  formed  by  the  kidneys. 

(1)  We  have  enlarged  a little  on  this  subject,  because  it  does  not  seem  completely 
exhausted  by  Todd’s  remarks,  since  the  publication  of  our  Handbuch  der  patholo- 
gischen Anatomic,  vol.  i.  pt.  2.  p.  416. 

(2)  Buhle,  De  hernia  obturatoria,  Halle,  1819. 

(3)  Zwanziger,  De  herniâ  diaphragmaticâ , Halle,  1819. 


Vor,.  III. 


G2 


486 


DESCRIPTIVE  ANATOMY. 


IX.  INTERNAL  HERNIAS. 

§ 2553.  The  internal  hernias(  1)  are  occasioned  by  abnormal  open- 
ings, or  by  culs-de-sac  existing  in  the  cavity  of  the  abdomen. 

1st.  Abnormal  openings  exist  sometimes  in  the  internal  portion  of 
the  peritoneum,  that  which  always  occurs,  and  sometimes  form  after 
partial  adhesions  between  parts  which  should  be  separated. 

The  openings  of  the  first  kind,  which  are  more  rare,  occur  princi- 
pally in  the  mesentery.(2) 

Those  of  the  second  class  may  be  developed  in  all  parts.  We  have 
observed  almost  all  of  them  in  cadavers.  The  partial  adhesions  which 
give  rise  to  them,  may  take  place, 

a.  Between  several  portions  of  the  intestine. 

b.  Between  the  small  intestine  and  the  anterior  edge  of  the  liver. 

c.  Between  the  upper  face  of  the  liver  and  the  upper  wall  of  the 
peritoneum. 

d.  At  the  summit  of  a diverticulum  of  the  ileon,  especially  by  a fila- 
ment which  still  exists  there,  and  which  is  formed  by  the  remnant  of 
the  omphalo-mesenteric  vessels. (3) 

e.  Between  the  vermiform  appendix  of  the  cæcum  and  a portion  of 
the  mesentery,  the  intestinal  canal,  and  the  uterus. (4) 

/.  Between  the  epiploon  and  the  base  of  the  uterus,  or  any  other 
abdominal  organ,  or  even  the  parietes  of  the  peritoneum.  It  is  the 
most  common  of  all  the  adhesions.(5) 

g.  Between  the  ovary,  especially  when  it  is  enlarged,  and  the  base 
of  the  uterus. 

2d.  Abnormal  depressions  are  formed  by  the  mesentery, (6)  the  blad- 
der,^) the  vagina. (8)  In  the  last  case  the  bladder  is  situated  in  the 
wall  of  the  vagina,  particularly  the  anterior,  which  is  then  turned 
over. (9) 

(1)  Meyer,  De  strangulationibus  intestinorum  in  cavo  abdominis , Strasburg-, 

1776. 

(2)  Heuermann,  Chir.  opérât.,  vol.  i.  p.  627. — Sauccrottc,  in  the  Mém.  de  Vac.  de 
ehir.,  vol.  iv.  p.  239. — Monro,  Anat.  of  the  gullet,  p.  537. 

(3)  Van  Dceveren,  Annot.  acad.  V. — Monro,  loc.  oit.,  tab.  xx.  p.  638. 

(4)  Monro,  Phys,  essays  of  Edinb.,  vol.  ii.  p.  402. — -Otto,  Pathol.  Anat.,  p.  280. 

(5)  Ruysch,  Obs.  anat.,  65. — Monro,  Anat.  of  the  gullet,  p.  533. — J.  P.  Weid- 
mann, Memoria  casus  rari  in  gynœceis  prœcipue  adnolandi  ; cum  uteri  anticâ  facie 
omenti  margo  ex  aliquâ  parte  coaluerat  ; prœgnans  fœtu,  medium  graviditatis  non 
assecuta,  inopinato  moritur,  Munich,  1818. — Gartshore,  in  the  Med.  obs.  and  inq., 
vol.  iv.  p.  223. — Haen,  Rat.  med.,  pt.  ii.  c.  iii.  § 2. — Knoblauch,  Diss.  de  entero-mcso- 
eqtocele,  Leyden,  1767. 

(6)  Neubauer,  Descript,  anat.  rarissimi  peritonæi  conceptaculi  tenuia  intestina  a 
reliquis  abdom.  vise,  seclusa  tenentis,  Jena,  1776. — Van  der  Kolk,  Diss.  exhibens 
observ.  varii  argumenti,  Groningen,  1793. — Lawrence,  loc.  cit. 

(7)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  ii.  p.  467. — Cooper,  Ueber 
Brüche,  p.  96. 

(8)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  ii.  p.  450. 

(9)  Clarke,  Diseases  of  females,  tab.  iv. 


OF  THE  ABDOMINAL  CAVITY' 


487 


We  conceive  that  these  parts,  which  are  then  lodged  in  one  of  these 
depressions,  can  undergo  the  same  changes  as  in  an  external  hernia. 

B.  ALTERATIONS  IN  TEXTURE. 

2554.  We  ought  to  mention  particularly  the  alterations  in  the  tex- 
ture of  the  peritoneum,(l)  and  which  are  common  to  it  with  the  other 
serous  membranes. 

This  membrane  is  frequently  inflamed  in  a greater  or  less  extent, 
and  thus  more  or  less  broad  and  firm  adhesions  are  formed.  Inflam- 
mation of  it  also  produces  either  in  its  external  or  internal  layer,  an  in- 
duration, a thickening  which  is  often  very  great,  several  lines  in  ex- 
tent. This  alteration  is  caused  particularly  by  a long  continued  in- 
flammation. We  may  also  mention  another  which  depends  on  the 
same  cause,  and  is  almost  peculiar  to  the  peritoneum  : it  is  the  deve- 
lopment on  its  inner  face,  of  numerous  small  miliary  elevations. 

The  abdominal  cavity  is  very  frequently  the  seat  of  dropsy,  which  is 
there  called  ascites.  Serum  most  generally  occupies  the  whole  cavity  : 
in  some  cases  only  the  epiploa  are  filled. 

Sometimes  considerable  masses  of  fat  are  developed  on  the  inner 
face  of  the  peritoneum,  even  in  persons  not  very  fleshy.  The  great 
epiploon  particularly,  presents  frequent  instances  of  this  anomaly,  and 
it  has  then  weighed  thirty  pounds. (2) 

Ossifications  on  the  external  face  of  the  peritoneum  are  rare  : but  we 
frequently  see  them  at  intervals  on  its  internal  face,  particularly  on  the 
surface  of  the  spleen.  The  epiploon  sometimes  presents  a similar  for- 
mation.^) 

Rounded,  cartilaginous,  and  osseous  masses,  similar  to  those  found 
loose  in  the  articulations,  are  rarely  developed  on  the  inner  face  of  the 
peritoneum  : they  finally  become  loose,  leaving  their  attachments. 

Hairs  occur  in  the  epiploon  still  more  rarely. 

We  not  unfrequently  find  on  the  two  faces  of  the  peritoneum,  and 
in  the  epiploa,  serous  cysts,  and  larger  or  smaller  masses  of  hydatids. 
The  serous  cysts  also  are  sometimes  detached  and  become  loose. (4) 

The  external,  and  more  frequently  the  internal  layer,  particularly  the 
epiploa  and  the  mesenteries,  also  are  frequently  the  seat  of  accidental 

(1)  J.  G.  Walter,  De  morbis  peritonœi,  Berlin,  1787. — Goelicke,  De  mesentcrii  affcc- 
tibus,  Halle,  1742. — Stock,  loc.  cit. — Rcebmann,  loc.  cit. — Haider,  De  morbis  omenti, 
Gottingen,  1786. — A.  Portal,  Observations  sur  les  tumeurs  et  engorgemens  de  V épi- 
ploon ; in  the  Mém.  sur  plus,  maladies , vol.  i.  1800.  p.  67.— Scoutetten,  Mémoire 
sur  V anatomie  pathologique  du  péritoine  ; in  the  Archiv,  gcn.  de  méd.,  vol.  iii.  p. 
497;  vol.  iv.  p.  386;  vol.  v.  p.  537. — D.  V.  Yan  Leuwen,  De  peritonœo  ejusque  in- 
fiammatione,  Utrecht,  1819. 

(2)  Portal,  Anat.  méd.,  vol.  v.  p.  127. 

(3)  Mongin,  Sur  la  pétrification  de  l'épiploon,  Paris,  1735. 

(4)  Desbas,  De  hydrope  peritonœi  saccato,  Gottingen,  1761. 


48S 


DESCRIPTIVE  ANATOMY. 


formations,  of  more  or  less  solid  whitish  substances,  which  are  de- 
scribed as  atheromata,  steatomata,  &e.,  and  which  frequently  become 
heavier  than  the  fatty  tumors  mentioned  above. 

Ruptures  of  the  reservoirs  in  the  abdomen,  produce  effusions  into  its 
cavity  of  bile,  blood,  or  of  the  contents  of  the  intestines  or  the  uterus. 

The  air  which  sometimes  fills  the  cavity  of  the  peritoneum,  or  only 
that  of  the  epiploa,  comes  from  the  same  source  in  some  cases.  But 
probably  this  is  not  always  its  origin,  for  sometimes,  although  very 
rarely,  this  fluid  is  exhaled  by  the  vessels,  the  action  of  which  is 
changed. 


EMBRYOLOGY. 


489 


BOOK  VIL 


EMBRYOLOGY. 

§ 2555.  When  all  the  parts  of  the  body  have  acquired  their  res- 
pective and  normal  proportions,  and  the  genital  organs  also  are  per- 
fectly developed,  the  individual  is  fit  to  propagate  the  species  by 
connection  with  an  individual  of  the  other  sex.  In  describing  the 
perfect  state  of  the  genital  system,  we  have  already  mentioned  the 
conditions  on  the  part  of  these  organs,  in  order  that  coition  may  be 
productive.  The  connection  of  the  two  sexes  causes  in  the  female 
those  changes  which  result  in  producing  a new  organism,  and  which 
is  termed  conception^  1) 


CHAPTER  I. 

CONCEPTION  IN  THE  NORMAL  STATE. 

§ 2556.  Before  detailing  the  phenomena  presented  by  conception 
we  must  establish  the  following  corollaries  : 

1st.  The  fetus  is  produced , and  not  merely  developed,  since  we  per- 
ceive no  trace  of  it  before  coition  followed  by  impregnation. 

(1)  The  works  we  shall  mention  treat  more  or  less  perfectly  of  the  changes  in  the 
organism  of  the  female  and  of  those  in  the  new  being: — J.  C.  Aranzi,  De  humano 
fœtu  libellus,  Venice,  1751. — Fabrice  of  Aquapendente,  De  formata  fœtu , Padua, 
1604. — G.  Harvey,  Exercitationes  de  generatione  animalium,  London,  1651. — C. 
Drelincourt,  De  conceptû,  Leyden,  1685.—  M.  R.  Besler,  Admirandæ  fabriccc  hu- 
manes muliebris  partium  generationi  inservicntium  et  fœtus  fidelis  quinque  tabulis, 
hactenus  nunquam  visis , delineatio,  Nuremberg,  1640. — Haller,  Historia  nuperœ 
dissectionis  feminœ  gravidœ,  Gottingen,  1734. — G.  Noortwyk,  Uteri  humani  gra- 
vidi  anatome  et  historia , Leyden,  1743. — D.  Monro,  The  dissection  of  a woman  with 
child,  and  remarks  on  gravid  uteri  ; in  the  Ed.  phys.  and  liter,  essays,  vol.  i.,  art. 
17. — A.  Monro,  Additional  observations  on  gravid  uterus  ; ibid.,  art.  18. — J.  G. 
Rcederer,  leones  uteri  humani  observationibus  illustrates,  Gottingen,  1759. — C.  N. 
Jenty,  Demonstratio  uteri  prœgnantis  mulieris  cum  fœtu  ad  partum  matur.,  Nu- 
remberg, 1761. — Azzoguidi,  Observationes  ad  uteri  constructionem  pertinentes,  Bo- 
logna, 1773. — G.  Hunter,  Anatomia  uteri  gravidi  tabulis  illustrata,  Birmingham, 
1774.— E.  Sandifort,  De  utero  gravido  ; in  the  Obs.  anat.  pathol.,  vol.  ii.,  Leyden, 
1778. — J.  Burns,  Anatomy  of  the  human  gravid  uterus,  Glasgow,  1797.— Moreschi, 
De  utero  gravido,  Milan,  1817. — Maygrier,  Nouvelles  démonstrations  d'accouchc- 
•mens,  Paris,  1822. — Mad.  Boivin,  Mémorial  de  l’art  des  accouchemens,  Paris,  1824. 


490 


DESCRIPTIVE  ANATOMY. 


2d.  The  most  general  condition  necessary  to  produce  it  is  the  action 
of  the  normal  seminal  fluid  of  the  male  on  the  genital  organs  of  the 
other  sex,  in  a state  of  maturity,  and  when  their  vitality  is  exalted, 

3d.  The  most  important  of  the  special  conditions  is  the  necessity  of 
a certain  relation,  a certain  resemblance,  between  the  male  and  the 
female  organism.(l) 

The  first  problem  to  resolve  is  the  mode  in  which  the  semen  of  the 
male  produces  conception.  On  this  subject  there  are  two  opinions  : 

1st.  Some  admit  that  the  semen  arrives  at  the  ovary  through  the 
uterus  and  the  Fallopian  tube  ; that  it  causes  directly  the  changes 
which  occur  in  this  organ,  and  even  that  its  substance  unites  more  or 
less  in  the  uterus  with  the  product  of  the  ovary,  to  give  rise  to  the 
new  organism. 

2d.  Others  think  that  the  semen  does  not  act  on  the  ovary  directly, 
but  only  secondarily,  by  a change  which  it  causes  in  the  whole  or- 
ganism or  in  the  genital  organs,  and  does  not  contribute  by  its  proper 
substance  to  form  the  new  organism. 

The  principal  facts  in  support  of  the  first  hypothesis  are  : 

1st.  The  necessity  of  a channel  for  the  semen,  in  order  that  the 
impregnation  may  occur,  since  it  does  not  happen  when  the  cavity  of 
the  female  genital  organs  is  interrupted. 

2d.  The  semen  found  in  the  uterus  and  the  Fallopian  tubes  in  fe- 
males who  died  during  or  shortly  after  coition. 

3d.  The  necessity  of  copulation  even  to  produce  a new  organism, 
for  it  is  difficult  to  admit  that  impregnation  may  occur  equally  in  any 
part  of  the  body  destitute  of  an  epidermis,  or  at  least  covered  by  an  epi- 
dermis as  thin  as  that  of  the  genital  organs,  as  has  been  asserted. (2) 

4th.  The  analogy  of  those  animals  in  which  the  eggs  are  impreg- 
nated on  leaving  the  body  of  the  female  by  the  semen  of  the  male. 

But  these  facts  are  not  sufficient  to  demonstrate  the  exactness  of 
the  hypothesis  they  are  adduced  to  support  : 

1st.  In  regard  to  the  first  argument,  sterility  may  possibly  depend 
on  other  causes,  and  besides  it  would  follow  only  that  the  semen  must 
necessarily  act  on  a certain  organ,  as  the  uterus  or  vagina,  in  order 
that  impregnation  may  occur. 

2d.  Perhaps  the  fluid  found  in  the  uterus  and  Fallopian  tubes  was 
not  semen,  but  was  secreted  by  the  female  genital  organs,  and  this  is 
often  found  in  the  cavity  of  these  two  organs. 

3d.  The  third  argument  proves  only  that  the  semen  must  act  on  a 
certain  organ. 

4th.  The  fourth  proves  at  most  that  the  condition  mentioned  is  ri- 
gorous in  the  animals  to  which  it  relates.  Still  it  does  not  even  de- 

(1)  Wolstein,  Ucber  das  Paaren  und  Verpaaren  der  Menschen  und  Thiere,  Al- 
tona, 1815. 

(1)  Treviranus,  Biologie,  vol.  iii.  p.  407. 


EMBRYOLOGY. 


491 


monstrate  this,  as  the  ova  of  these  animals  are  surrounded  by  a thick 
layer  of  mucus. 

We  may  also  adduce  against  this  hypothesis  and  in  the  support  of 
the  second  the  following  arguments  : 

1st.  The  experiments  in  which  yellow  bodies  at  least  have  been 
developed,  although  the  Fallopian  tubes  had  been  carefully  tied.(l 

2d.  In  careful  experiments  on  generation  semen  has  seldom  been 
found  in  the  uterus,  and  the  consequences  of  conception  are  not  mani- 
fested till  several  days  or  weeks  after  coition. 

3d.  In  most  animals  the  genital  organs  are  so  arranged,  that  on 
account  of  their  length  and  tortuousness  in  the  females,  the  marked 
prominences  on  the  neck  of  the  uterus,  and  the  shortness  of  the  male 
organs,  it  seems  almost  impossible  for  the  semen  to  arrive  at  the 
ovaries. 

4th.  The  uniform  sensation  of  pleasure  and  numerous  general  signs 
which  attend  impregnation. 

Hence  it  follows  that  the  influence  of  the  male  is  confined  to  exalt 
the  formative  power  in  the  female  to  the  degree  necessary  to  produce 
the  new  being.  This  increase  is  manifested,  as  we  shall  soon  state, 
by  the  direct  formation  in  the  ovary  of  a new  organ,  a temporary 
testicle , which  secretes  a fluid  possessing  the  power  of  spontaneous 
growth. 


ARTICLE  FIRST. 


OF  THE  CHANGES  IN  THE  GENITAL  ORGANS  PRODUDED  BY 
COITION  AND  CONCEPTION.(2) 

I.  ORGANS  OF  COITION. 

§ 2557.  Coition  usually  changes  the  external  genital  organs  very 
much  ; the  hymen  is  generally  more  or  less  perfectly  destroyed.  Its 
remains  give  rise  to  the  cancnculoi  myrtiformes , which  term  applies  to 
three  or  four  small  eminences,  most  generally  triangular,  which  are 
situated  on  the  sides  and  posterior  parts  of  the  vagina.  The  existence 
of  the  hymen  is  not,  however,  a certain  mark  of  physical  virginity  : 
first,  because  this  membrane  has  frequently  been  found,  not  only  in 
females  who  had  several  times  had  connection, (3)  but  also  in  others 
who  had  given  birth  to  fetuses  more  or  less  advanced,  and  fetuses  even 

(1)  J.  Haighton,  in  the  Phil.  Irans.,  1797. 

(2)  S.  Pineau,  Dc  virginitatis  notis,  graviditate  el  partu,  Leyden,  1654. 

(3)  Osiander  ( loc . cit. . p.  24)  mentions  several  cases  of  it. 


492 


DESCRIPTIVE  ANATOMY. 


seven  months  old  ;(1)  and  second,  because  it  may  have  been  destroyed 
from  other  causes,  and  even  may  not  exist  from  a primitive  deviation 
of  formation. 

The  enlargement  of  the  vagina  and  the  disappearance  of  its  corru- 
gations are  still  less  constant  and  sensible. 

II.  FORMATIVE  ORGANS. (2) 

A.  OVARIES. 

§ 2558.  The  internal  organs  of  generation  are  modified  not  by  coi- 
tion, but  only  by  conception. 

A special  body,  termed  the  yelloiv  or  glandular • body  {corpus  luteum , 
s.  glandulosum),{3 ) is  developed  in  the  ovary.  It  is  a rounded,  soft, 
very  vascular  tissue,  composed  of  several  lobes  ; it  projects  above  the 
surface  of  the  ovary,  becomes  about  as  large  as  a cherry,  and  incloses 
a cavity  which  opens  externally.  The  number  of  the  yellow  bodies 
usually  corresponds  to  that  of  the  new  organisms  which  have  been 
formed. 

From  experiments  on  animals,  these  bodies  arise  from  the  change 
of  one  and  not  probably  of  several  of  the  vesicles  of  Graaf,  which,  from 
being  a simple  serous  membrane,  is  changed  into  a glandular  organ, 
that  is,  its  organism  becomes  more  complex,  and  it  acquires  the  faculty 
of  producing  a liquid  different  from  the  serum  of  the  vesicles.  As  the 
yellow  body  differs  in  its  structure  from  all  the  other  glands,  the  fluid 
it  secretes  has  also  peculiar  characters  : it  is  the  generating  fluid,  the 
semen  of  the  female. 

The  influence  of  the  male  semen  is  the  usual  and  regular  cause  of 
this  change,  which  however  seems  to  occur  also  from  the  effect  of 
other  stimuli,  perhaps  of  the  imagination  or  unnatural  indulgences. 
In  fact  several  rare  cases,  where  yellow  bodies  have  been  found  in 
unmarried  females  and  virgins,  and  always  attended  with  the  pheno- 
mena mentioned  above,  lead  us  to  think  that  the  formation  of  these 
bodies  had  been  preceded  by  the  act  of  coition,  and  by  impregnation. 
However  as  they  have  been  found  in  animals  generally  sterile,  as 
mules,  our  opinion  as  concerns  females  is  very  probable  ; but  we  are 
not  authorized  by  facts  to  think  that  the  change  of  the  vesicles  of 

(1)  Tolberg1 2 3,  De  var.  hym .,  p.  14. — We  have  in  our  cabinet  the  anatomical  speci- 
men, which  is  very  remarkable. 

(2)  M.  Malpighi,  De  cornuum  vegetationc,  utero , viviparum  oris  ; in  the  Opp. 
omn.,  Leyden,  1637,  vol.  i.  p.  211.— A.  Bertrandi,  Observations  sur  les  corps  glandu- 
leux, sur  la  matrice  et  sur  l'ovaire  dans  l'état  de  grossesse;  in  the  Miscell.  l'aur., 
vol.  i.  1758. 

(3)  Brugnone,  De  ovariis  corum,que  corpore  luteo  cbservationcs  anatomicce  ; in  the 
Mem.  de  Darin,  1790.— Itoose,  U eher  die  gelben  Körper  und  Eierstöche , Bruns- 
wick, 1800. 


EMBRYOLOGY. 


49S 


Graaf  into  yellow  bodies  can  be  produced  except  by  an  unusual  in- 
crease in  the  propensity  to  generational ) 

Some  have  mentioned  yellow  bodies  found  in  newly  born  or  very 
young  animals  ; but  it  is  easy  to  reply  to  this  objection  that  every  yel- 
low substance  found  in  the  ovary  is  not  a yellow  body.  Nor  is  the 
argument  drawn  from  the  fact  that  the  number  of  the  yellow  bodies 
does  not  always  correspond  to  that  of  the  offspring,  conclusive.  If  the 
number  of  yellow  bodies  be  fewer  than  that  of  the  offspring  produced 
by  the  female,  this  circumstance  agrees  with  their  signification,  since 
one  yellow  body  as  well  as  one  testicle  may  produce  several  new  or. 
ganisms.  Farther  one  or  more  of  these  bodies  also  might  disappear 
or  several  be  blended  together.  In  the  case  where  they  were  more 
numerous  than  that  of  the  offspring  : 1st,  it  is  necessary  to  mention 
exactly  if  these  which  were  supernumerary  did  not  arise  from  anterior 
conceptions  ; 2d,  it  would  be  possible,  even  in  admitting  that  the  ani- 
mal has  never  conceived  previously,  that  generation  has  not  proceeded 
beyond  the  production  of  a yellow  body,  or  that  its  production  was 
lost.  Besides  we  are  very  much  disposed  to  consider  as  very  uncer- 
tain, observations  in  the  cases  where  it  is  pretended  that  the  number  of 
yellow  bodies  and  that  of  the  offspring  differed,  for  the  examination  of 
more  than  two  hundred  women,  and  females  of  different  mammalia  in 
the  state  of  pregnancy,  has  convinced  me,  that  the  number  of  yellow 
bodies  which  from  the  absolute  identity  of  all  their  characters  may  be 
considered  as  produced  by  the  same  generating  act , always  corresponds 
to  that  of  the  young.  Observers  known  for  their  correctness  have 
come  to  the  same  conclusion, (2)  while  contrary  assertions  do  not  ap- 
pear to  be  well  supported. 

The  cavity  of  the  yellow  body  is  gradually  obliterated  ; the  body 
itself  diminishes,  collapses,  and  hardens.  These  changes  do  not 
happen  exactly  at  the  same  period,  and  we  have  remarked  generally 
in  the  human  species  or  in  animals,  at  least  in  respect  to  the  size  of 
the  body,  they  are  not  very  large  during  pregnancy,  while  after  partu- 
rition they  evidently  increase  more  rapidly.  This  phenomenon  is 
worthy  of  notice,  as  it  teaches  us  that  although  the  function  of  the 
yellow  body  and  the  ovary  generally  has  passed  at  this  period,  vitality 
however  continues  to  be  more  active  in  them  on  account  of  the  great 
degree  of  vitality  in  the  uterus.  Farther  the  yellow  body  rarely  dis- 
appears entirely,  although  it  diminishes  extremely. 

Halier(3)  and  several  others  since  his  time  have  attributed  the  dis- 
covery of  the  yellow  bodies  to  Yolcher  Coiter  ;(4)  but  it  really  belongs 

(1)  Joerg,  l’on  der  Zeugung , p.  151. 

(2)  Haller,  El  phys.,  vol.  viii.  pt.  ii.  p.  29-38. — Hunter,  Anatomische  Beschreibung 
des  menschlichen  schwängern  Uterus , Weimar,  1802,  p.  20. 

(3)  Et  phys.,  vol.  viii.  p.  33. 

(4)  Obs.  anat.,  1573,  p.  124.  Vcsiculcc  queedam  continebant  aquam  limpidam, 
queedam  luteum  humorum. 


VOL.  III. 


63 


494 


DESCRIPTIVE  ANATOMY. 


to  Fallopius,(l)  who  mentioned  these  bodies  twelve  years  before 
Coiter,  and  nearly  in  the  same  language. 

Malpighi(2)  and  Graaf(3)  discovered  their  uses. 

§ 2559.  According  to  Osiander(4)  the  vesicles  of  Graaf  and  the 
yellow  bodies  have  no  connection  with  generation,  because  the  former 
have  no  openings.  He  asserts  that  after  coition  the  parts  which  are 
changed  into  new  organisms  are  developed  on  the  surface  of  the  ovary 
in  the  form  of  miliary  vesicles,  one  of  which  is  detached  and  falls  into 
the  uterus.  He  adds  that  we  must  consider  these  corpuscles  as  ova  : 
1st,  because  they  never  appear  before  impregnation  ; 2d,  because  they 
are  always  observed  after  coition  followed  by  impregnation  ; 3d,  be- 
cause many  are  found  in  the  cadavers  of  young  females  dying  after  a 
few  pregnancies  ; 4th,  because  many  are  turgescent,  others  empty, 
and  finally  others  resemble  simple  cicatrices  ; 5th,  because  they  dis- 
appear entirely  when  the  female  is  sterile. 

These  reasons  do  not  seem  satisfactory  to  us.  The  vesicles  men- 
tioned may  be  developed  after  copulation  and  disappear  during  life, 
although  there  were  in  fact  no  ova,  since  coition,  when  followed  by 
conception,  produces  as  great  and  to  a certain  extent  even  analogous 
changes  in  remote  parts  and  in  the  whole  organism. 

Besides  we  have  frequently  found  the  ovaries  of  females,  physically 
and  morally  virgins,  covered  with  a very  dense  miliary  eruption,  and 
in  them  the  vesicles  were  too  numerous  to  admit  Osiander’s  opinion  in 
respect  to  them. 

Finally  we  may  alledge  against  this  hypothesis  the  exact  history 
of  the  changes  in  the  vesicles  of  Graaf  after  impregnation. 

The  only  argument  adduced  by  Osiander  to  reject  the  use  attributed 
to  the  vesicles  of  Graaf  has  no  weight  except  against  an  unimportant 
opinion,  that  the  vesicle  itself  is  detached,  and  that  the  yellow  body 
grows  in  its  place  ; but  this  has  no  weight  at  all  when,  as  seems  to  us 
more  correct,  we  consider  the  yellow  body  a vesicle’changed,  which, 
according  to  all  observations,  is  provided  on  the  surface  of  the  ovary 
with  an  opening  communicating  with  its  cavity,  and  through  which 
the  formative  fluid  may  escape. 

B.  FALLOPIAN  TUBES. 

§ 2560.  The  only  change  produced  by  coition  in  the  Fallopian 
tubes  is  this  ; soon  after  this  act  they  are  applied  to  the  ovaries,  so  as 
to  embrace  a greater  or  less  portion  with  their  fimbriated  extremity, 

(1)  Obs.  anat.,  Venice,  1561.  Vidi  quidem  in  iisdem  ( ovariis ) quasdam  veluti 
vesicas  aqua  vel  humore  aqueo,  alias  lutco,  alias  vero  limpido  turgentes  ; in  the  Opp. 
omn .,  Venice,  1606,  p.  106. 

(2)  Loc.  cit , p.  223. 

(3)  Lee.  cit. , p.  331. 

(4)  Handbuch  der  Entbindungskur,  v Hingen,  1802,  vol.  i p 129-145. 


EMBRYOLOGY. 


495 


and  to  receive  the  fluid  poured  out  by  the  yellow  body,  which  they 
then  carry  into  the  uterus. 

Their  approximation  to  the  ovaries  is  favored  by  the  portion  of  small 
intestine  situated  in  the  lower  pelvis  ; for  this  portion  tenses  the  liga- 
ments of  the  ovaries  and  the  broad  ligaments  of  the  uterus,  thus  fixes 
the  glands  in  their  position,  and  applies  the  tubes  to  their  surface,  so  that 
they  extend  a little  on  the  outside  of  them.(l) 


c.  UTERUS. 

§ 2561.  The  structure  of  the  uterus(2)  undergoes  remarkable 
changes  in  many  respects,  and  the  new  organism  is  developed  within  it. 

Even  before  we  perceive  any  trace  of  the  new  being,  we  already  find 
the  uterus  a little  enlarged  at  its  upper  part,  its  substance  is  softer, 
looser,  more  lamellar,  its  component  layers  are  more  distinct,  its  ves- 
sels are  dilated,  its  inner  face  is  smooth  but  irregular,  extremely  vas- 
cular, and  also  covered  with  numerous  very  minute  flocculæ,  which 
cannot  be  seen  except  with  a microscope,  and  finally  it  is  covered  with 
a pultaceous  matter  into  which  the  vessels  extend,  and  which  passes  on 
the  neck  of  the  organ,  so  as  to  close  the  cavity  of  the  body.  This 
substance  resembles  coagulated  blood.  It  is  thickest  at  its  upper  part, 
where  it  is  connected  with  the  uterus  more  intimately  than  in  any 
other  place.  Below  it  is  very  thin  and  united  to  the  organ  more 
loosely,  and  even  does  not  adhere  to  it  at  all. (3) 

The  vaginal  orifice  and  the  neck  are  also  filled  with  a viscous, 
shining  substance,  similar  to  gelatine. 

These  changes  increase  uninterruptedly  until  the  end  of  pregnancy, 
which  generally  continues  ten  lunar  months. 

The  fibrous  texture  becomes  more  and  more  distinct  : it  cannot  well 
be  perceived(4)  except  during  pregnancy  or  in  analogous  states  of  the 
uterus,  when  this  organ  also  enlarges,  as  for  instance,  when  abnormal 
formations  are  developed  within  it.  It  is  then  certain  that  if  the  fibres 
do  not  form  during  pregnancy  they  are  at  least  developed  and  very 
much  enlarged  at  that  time. 


(1)  Autenrieth,  Ueber  die  eigentliche  Lage  der  innern  weiblichen  Geschleeht- 
stheile  ; in  Reil,  Archiv,  für  die  Physiologie,  vol.  vii.  p.  294. 

(2)  Beside  the  works  already  mentioned  in  respect  to  the  uterus,  consult  also  : 
A.  Vater,  De  utero  gravido,  YVittemberg-,  1725. — Beyer,  Utrum  in  gravidis  lotus 
uterus  cequaliter  extendatur , Paris,  1729.- — P.  A.  JBoehmer,  Situs  uteri  gravidi 
fœtusque , ac  sedes  in  utero,  Halle,  1748. — B.  S.  Albinus,  Tabulce  uteri  gravidi,  Ley- 
den, 1748. — Id.,  De  utero  gravido  nonnulla  ; in  the  Annot.  acad.,  1.  ii.  cap.  v. — J. 
Weitbrecht,  De  utero  muliebri  (gravido)  observationes  anatomicœ  ; In  N.  C.  Petrov., 
vol.  i.  p.  337. 

(3)  Pke  case  of  a young  woman  who  poisoned  herself  in  the  first  month  of  her 
pregnancy,  by  'Ph.  Ogle  ; to  which  is  added  an  account  of  the  appearances  after 
death,  by  J.  Hunter  ; in  the  London  med.  trans.  for  the  improvement  of  med.  and 
chir.  knowledge,  vol.  ii.  p.  63. 

(4)  This  remark  had  been  made  already  by  Vesalius  (De  corp.  hum.  fab.,  book  v. 
c.  xv.),  and  by  Santorini  after  him  ( Observ . anat.,  c.  x-i,  § 13). 


496 


DESCRIPTIVE  ANAT0MT. 


Hence  why  the  uterus,  although  it  enlarges  and  becomes  much 
softer,  is  not  only  distended  but  enlarges  considerably. 

Some  days  after  parturition  occurs,  when  the  term  of  pregnancy 
has  been  normal,  the  uterus  weighs  at  least  twenty-four  ounces,  as  we 
have  proved  by  examining  twelve  cadavers  of  females  dying  at  this 
period  ; so  that  even  then,  although  the  organ  had  already  collapsed, 
its  weight  was  to  that  of  the  uterus  in  a virgin  as  24  : 1. 

Another  question  now  presents  itself,  viz.  do  the  parietes  of  the 
uterus,  which,  from  the  preceding  remarks,  are  not  only  distended,  but 
also  become  thicker,  remain  the  same,  or  do  they  grow  thinner  ? The 
latter  perhaps  is  true,  notwithstanding  the  increase  in  mass  and 
weight,  on  account  of  the  considerable  extension  of  the  uterus  during 
pregnane}^. 

This  problem  has  been  resolved  several  different  ways.(l) 

Those  who  admit  that  the  parietes  of  the  uterus  preserve  the  same 
thickness,  or  even  become  thicker,  explain  the  contrary  assertion  by 
saying  that  the  thickness  of  the  uterus,  considered  generally,  varies  in 
the  state  of  pregnancy, (2)  and  that  an  uterus,  when  filled  with  the 
product  of  conception,  has  not  the  same  thickness  in  every  part. (3) 
We  may  also  say  that  sometimes  the  uterus,  from  a pathological  state, 
is  not  properly  developed,  and  is  only  distended,  which  perhaps  is  one 
of  the  causes  which  contribute  to  render  parturition  painful. 

Our  observations  made  upon  sixteen  uteri  at  all  periods  of  gestation, 
lead  us  to  think  that  very  probably  the  parietes  become  a little  but  not 
much  thicker  at  first,  and  that  towards  the  end  of  pregnancy  they 
gradually  become  much  thinner. 

In  fact  we  have  found  the  parietes  of  the  uterus  six  lines  thick,  three 
weeks  after  conception  ; five,  at  the  beginning  of  the  third  month  ; four, 
at  the  commencement  of  the  fourth  ; at  the  end  of  this  month,  four  in 
two  cases:  three  at  the  upper  part,  and  four  at  the  lower  in  a third, 
and  five  in  a fourth  case  ; at  five  months,  three  lines  thick  in  one  case, 
two  at  the  upper  part,  and  four  in  the  lower  in  another  ; at  six  and  seven 
months,  a little  less  than  three  ; at  eight  months,  from  two  to  two  and 
a half  lines  in  one  case,  and  in  another,  three  lines  at  the  upper  part, 
and  more  than  four  at  the  lower  : they  have  appeared  to  us  a little 
thinner  at  nine  months. 

On  the  contrary  the  uterus  when  collapsed  after  parturition  is  gene- 
rally an  inch  thick  at  the  end  of  seven,  eight,  and  nine  months. 

The  veins  and  the  arteries  of  this  organ  are  extremely  dilated,  so 
that  the  venous  trunks  are  as  large  as  the  axillary  veins.  These  two 
orders  of  vessels  become  less  tortuous  as  the  uterus  enlarges. 

(1)  Hallor  has  collected  most  of  the  opinions  on  this  subject  (El  phys.,  vol.  viii.  p. 
2.  p.  58). 

(2)  For  instance,  F.  A.  Walter,  De  pohjpis  ; in  the  Anno/.  Ac.  Ecrol.,  1786,  p.  3. 

(3)  Hunter,  loc.  cit.,  p.  21. 


EMBRYOLOGY. 


497 


The  dilated  veins  of  the  uterus  have  very  improperly  been  termed 
sinuses. 

The  place  where  the  blood-vessels  are  most  developed  is  where  the 
new  organism  unites  directly  with  that  of  the  mother,  that  is,  at  the 
insertion  of  the  placenta. 

§ 2562.  The  form  of  the  uterus  is  also  considerably  changed.  As 
the  body  only  of  the  organ  is  developed  during  most  of  pregnancy,  the 
disproportion  between  it  and  the  neck  always  becomes  greater,  and 
even,  as  when  the  neck  is  finally  distended,  in  the  latter  periods  of 
pregnancy  it  shortens  in  proportion  as  it  enlarges,  the  disproportion 
only  becomes  still  more  perceptible,  so  that  the  uterus  is  rather  oval 
than  pyriform,  especially  near  parturition. 

This  organ  also  becomes  considerably  thicker  from  before  backward 
in  proportion  to  its  breadth  than  it  was  before,  although  it  still  conti- 
nues to  be  a little  more  broad  than  thick. 

The  orifice  of  the  vagina  begins  to  become  round  at  the  first  month. 

§ 2563.  Great  changes  supervene  also  in  the  situation  of  the 
uterus. 

During  the  first  two  months  of  pregnancy  the  uterus  gradually  de- 
scends a little  in  the  pelvis,  so  that  its  orifice  is  more  easily  perceived 
with  the  finger  introduced  into  the  vagina  ; but  at  three  months  it 
begins  to  reascend,  and  also  changes  its  direction,  its  base  goes  farther 
forward,  and  its  orifice  backward.  These  changes  increase  so  much, 
as  pregnancy  advances,  that  it  becomes  more  and  more  difficult  to 
reach  the  os  tincæ,  and  more  so  as  the  lower  part  of  the  anterior  wall 
of  the  uterus  is  crowded  from  above  downward,  before  it,  by  the  lower 
part,  the  head  of  the  child.  In  most  cases,  in  proportion  as  the  uterus 
is  developed,  its  base  rises,  and  becomes  evident  through  the  distended 
integuments  of  the  abdomen. 

The  anterior  face  of  the  organ,  especially  in  the  latter  months  of 
pregnancy,  is  situated  directly  behind  the  anterior  wall  of  the  abdo- 
minal cavity.  It  pushes  the  small  intestine  upward,  backward,  and 
on  the  sides  ; at  least  this  intestine  very  rarely  descends  between  the 
uterus  and  the  anterior  wall  of  the  abdomen,(l)  and  this  case  probably 
never  happens  at  the  end  of  gestation. 

§ 2564.  After  parturition  the  uterus  contracts,  and  in  a few  days  its 
parietes  are  more  than  an  inch  thick. (2) 

Its  volume  returns  gradually,  and  even  during  the  first  few  weeks, 
to  the  size  it  had  before  pregnancy  ; its  vessels  contract,  and  at  the 
same  time  its  loose  and  lamellar  structure  disappears.  It  however 
always  remains  larger  and  softer  than  in  a female  who  has  never 
borne  children.  It  begins  to  diminish  much  and  to  become  harder 
only  at  an  advanced  age. 

(1)  1).  Monzo,  in  the  Edinb.  Essays,  an.  ob.,  vol,  i.  p.  456.  At  the  sixth  month  of 
pregnancy. 

(2)  Hunter,  loc.  cit. 


498 


DESCRIPTIVE  ANATOMY. 


The  orifice  of  the  vagina,  which  in  the  latter  period  of  pregnancy 
had  become  a rounded  opening,  resumes  its  ancient  form  : but  it  is 
generally  torn  more  or  less  deeply,  whence  it  is  uneven  and  corru- 
gated. The  lips,  particularly  the  posterior,  are  thicker  and  longer. 
They  are  adapted  to  each  other  less  exactly. 


ARTICLE  SECOND. 


DEVELOPMENT  OF  THE  NEW  ORGANISM.(l) 

§ 2565.  The  first  origin  of  the  new  organism  is  very  obscure.  We 
do  not  know  whether  the  fluid  secreted  in  the  yellow  body  directly 
assumes  any  form,  so  that  the  ovary  furnishes  a vesicle  filled  with 
liquid,  which  is  the  first  trace  of  the  ovum  or  of  the  envelops  ( involucra , 
s.  membranoe)  of  the  fetus  : or  if  this  change  takes  place  only  in  the 
tube,  perhaps  even  in  the  uterus. 

The  possibility  of  the  development  of  the  new  organism  in  the  ovary 
does  not  prove  that  the  fluid  of  the  vesicles  is  changed  there  in  the 
normal  state;  we  ought  only  to  conclude  that  when  this  fluid  does 
not  arrive  in  the  uterus  it  may  assume  in  every  other  part  the  form  of 
an  ovum. 

It  is  very  doubtful(2)  whether  the  ova,  discovered  in  the  Fallopian 
tubes, (3)  of  animals,  were  really  %hat  they  were  supposed  to  be,  and 
more  so  because  other  observations  render  another  mode  of  develop- 
ment probable,  and  particularly  that  the  ovum  takes  its  form  in  the 
uterus.  (4) 

But  there  is  a rounded  vesicle,  composed  of  several  membranes 
adapted  to  one  another,  and  containing  different  fluids,  constantly 
formed  before  the  fetus.  The  fetus  is  developed  within  the  ovum, 
which  connects  it  wfith  the  organism  of  the  mother.  As  the  human 
ovum  is  generally  ruptured  at  its  lower  part  at  the  period  of  parturi- 
tion, and  the  infant  is  delivered  before  it,  it  is  termed  the  secundines 
( secundo: , s.  secundinu). 

(1)  Beside  the  works  cited  above,  which  treat  also  of  the  changes  in  the  genital 
organs,  consult  : T.  Kerkring,  Anthropogenia,  Amsterdam,  1670. — M.  Schurig, 
Embryologia,  Dresden,  1732. — F.  G.  Danz  Grundriss  der  Zergliederungskunde  des 
ungebornen  Kindes , Frankfurt,  1792-1793. — C.  F.  Burdach,  De  primis  momentis 
formationis  fœtus,  Königsberg,  1814. — O.  C.  Lucæ,  Grundriss  der  Entwieklungs- 
geschichtc  des  menschlichen  Körpers,  Marburg,  1819. — Beclard,  Embryologie,  ou 
Essai  anatomique  sur  le  fœtus  humain,  Paris,  1820. 

(2)  Hartmann,  Dubia  de  generatione  viviparorum  ex  ovo,  Koningsberg,  1699, 

9 14. 

(3)  De  Graaf,  De  mulierum  organis,  cap.  xvi. — G.  Cruikshank,  in  the  Phil, 
frans.,  1797. 

(4)  J.  C.  Kuhlemann,  Observations  circa  generationis  negotium  in  ovibusfactœ, 
Gottingen,  1753.— Haller,  De  quadrupedum  utero,  conceptu  et  fœtu  ; in  the  Opp. 
min.,  vol.  ii.  p.  32. 


OF  THE  GENITAL  SYSTEM, 


-499 


I.  ENVELOPS  OF  THE  FETUS. 

§ 2566.  The  membranes  of  the  ovum(l)  are  much  larger  and  hea- 
vier the  farther  the  fetus  is  from  the  period  of  its  formation.  Taken 
with  the  fluid  they  contain,  they  are  at  first  much  heavier  than  the 
fetus,  and  they  even  weigh  more  than  it  at  the  end  of  the  third  month, 
after  being  emptied,  although  the  disproportion  is  then  less,  as  may 
easily  be  conceived.  At  the  end  of  the  third  month,  that  is,  after  about 
the  first  third  of  fetal  existence,  their  weight  is  nearly  equal.  After 
this  period  an  inverse  relation  exists,  so  that  the  mean  weight  of  the 
membranes  of  the  ovum  is  to  that  of  the  fetus  as  1 : 8,  since  a well 
grown  fetus  weighs  about  eight  pounds,  and  the  weight  of  the  se- 
cundines,  including  that  of  the  cord,  weighs  rather  more  than  one 
pound. 

The  first  trace  of  the  fetus  is  the  substance  which  fills  the  uterus 
soon  after  coition,  and  which  seems  to  be  only  coagulated  blood. 

This  substance  forms  the  most  external  membrane  of  the  ovum,  the 
deciduous  membrane. 


A.  DECIDUOUS  MEMBRANE. 

§ 2567.  The  deciduous  membrane,  épichorion,  Ch.  (JVf.  decidua,  s. 
caduca,  tunica  ovi  exterior , membrana  Hunteri),{2 ) which  surrounds 


(If  Beaide  the  works  already  mentioned,  particularly  those  of  Nortwyck,  Sandi- 
fort,  and  Hunter,  consult  : A.  Vater,  Mus.  anat.  propr.,  tab.  viii.  Wittemberg,  1701. 
— Ruyscb,  Thés,  anat.,  VI.  tab.  i.  and  ii.— G.  Vater,  Mola  prœgnans,  with  a plate. 
— O.  Borrich,  Abortus  humanus  examinatus  ; in  the  Act.  Hafn.,  vol.  ii.  p.  49. — B.  S. 
Albinus,  De  vasis  placentae  parvulorum  embryonum  et  de  involucro,  quo  édita  eorum 
ova  continentur  ; in  the  Annot.  acad.,  lib.  i-xvii. — Id.,  Nonnulla  de  embryonibus 
humanis  ovisque,  quibus  continentur,  ibid.,  xix. — P.  A.  Boehmer,  Instil,  osteol.,  Halle, 
1751,  tab.  i.  f.  7,  8.— D.  C.  Burdach,  De  lœsione  partium  fœtus  nutritioni  insertion- 
tium  abortus  causa,  Leipsic,  1768. — E.  Sandifort,  De  ovo  humano,  absque  ullo  fœtus 
indicio,  et  placentœ  in  hydatides  degeneratione  ; in  the  Obs.  anat.  path.,  book  ii-iii. 
p.  76. — Id.,  De  ovo  humano , ibid.,  book  iii-vi.  p.  91. — Blumenbach,  Institutiones 
phys.,  1787,  tab.  iv. — S.  T.  Sœmmerring,  Icônes  embryonum  humanorum,  Frankfort, 
1799. — Denman,  Practice  of  midwifery,  London,  1801,  tab.  vi-viii. — Wrisberg,  Obs. 
anat.  obst.  de  structura  ovi  et  secundinarum  humanarum  in  partu  naturali  et  per - 
fecto  collectas,  Gottingen,  1782. — C.  G.  Krummacher,  Diss.  sistens  observationes 
quasd.  anat.  circa  velamenta  ovihumani,  Duisburg,  1790. — J.  F.  Lobstein,  Essai  sur 
la  nutrition  du  fœtus,  Strasburg,  1802. — Samuel,  De  ovorum  mammalium  vêla- 
mentis,  Wurzburg,  1816. — Dutrochet,  Recherches  sur  les  enveloppes  du  fœtus  ; in 
the  Mém.  de  la  soc.  méd.  d’émul.,  vol.  viii.,  1817,  p.  1-60. — G.  Cuvier,  in  the  Mém. 
du  Museum , vol.  iii. — Dutrochet,  Observ.  sur  la  structure  de  l’œuf  des  mammifères 
et  examen  de  la  doctrine  de  Cuvier  sur  cette  matière  ; ibid.,  p.  760-767. — Dutrochet, 
Mém.  sur  les  enveloppes  du  fœtus  ; in  the  Journ.  compl.  du  Diet,  des  sc.  méd.,  vol. 
v.  p.  241. — Velpeau,  Sur  les  membranes  du  fœtus  ; in  the  Archiv,  gén.  de  méd.,  No- 
vember and  December,  1824. 

(2)  Haller,  Elem.  phys.,  vol.  viii.  p.  183. — Osiander,  Handbuch  der  Entbindung- 
skunde, pt.  i.  p.  191. — F.  J.  Moreau,  Essai  sur  la  disposition  de  la  membrane  ca- 
duque, sa  structure  et  ses  usages , Paris,  1814. 


500 


DESCRIPTIVE  ANATOMY. 


the  envelops  of  the  ovum  belonging  to  the  fetus,  is  attached  by  its 
inner  face  to  the  chorion,  and  by  its  external  face  to  the  inner  face  of 
the  uterus. 

It  is  entirely  different  from  the  other  membranes,  is  thicker,  more 
opaque,  but  infinitely  less  solid.  It  has  about  the  consistence  of  coa- 
gulated fibrine,  which  it  also  resembles  in  its  yellowish  color. 

Its  thickness  is  not  the  same  in  all  parts  of  its  extent.  It  is  gene- 
rally thicker  in  the  region  of  the  placenta,  and  smaller  at  the  lower 
part,  opposite  the  internal  orifice  of  the  uterus,  than  in  any  other 
point. 

It  always  diminishes  from  the  moment  of  its  origin,  so  that  finally 
it  is  scarcely  half  a line  thick.  Its  external  face  is  at  first  uneven  and 
corrugated  ; but  in  time  it  becomes  smoother,  as  is-  already  its  in- 
ternal face.  The  connections  which  unite  it  to  the  uterus  are  much 
looser  in  the  early  periods  than  at  the  end  of  pregnancy. 

It  presents  in  a greater  or  less  portion  of  its  extent  more  or  less  evi- 
dent perforations,  which  give  it  a reticulated  or  cribriform  appearance. 

It  receives  a great  number  of  vessels,  which  are  prolongations  of 
those  of  the  uterus,  and  which  descend  obliquely  into  it. 

§ 2568.  The  deciduous  membrane  not  only  surrounds  the  ovum  : it 
forms  a double  layer  around  it,  and  it  is  consequently  arranged  like 
the  serous  membranes. 

In  fact,  beside  the  portion  of  this  membrane  which  unites  it  by  its 
external  face  to  the  internal  face  of  the  uterus,  there  is  a second  which 
is  reflected  on  the  preceding,  and  is  contained  within  it. 

This  second  layer  is  attached  by  its  inner  face  to  the  chorion,  and  is 
loose  on  its  external  face,  while  the  other  fold  is  loose  on  its  internal 
face,  and  adheres  to  the  uterus  by  the  external. 

The  first  fold  of  the  membrane  is  called  the  external  or  true  deci- 
duous membrane  (AI.  decidua  externa,  s.  vera)  : the  other  is  termed 
the  internal  or  reflected  deciduous  membrane  (AI.  decidua  interna , s. 
reflexa ) ; it  has  also  very  improperly  been  termed  the  fungous  deci- 
duous membrane  (chorium  fungosum). 

The  arrangement  of  the  deciduous  membrane  however  differs  from 
that  of  the  serous  membranes,  because  the  external  fold  is  not  only 
reflected  upon  the  chorion,  but  also  on  leaving  this  point,  where  it  is 
inflected,  it  is  extended  on  the  latter,  which  it  consequently  envelops 
in  every  part.(l  ) 

(1)  Moreau  (he.  cit.,  p.  16)  rloes  not  assent  to  this  opinion.  When  the  ovum  is  sepa- 
rated from  the  uterus  it  seems  in  fact  enveloped  in  every  part  by  the  deciduous 
membrane  : but  according-  to  him,  as  the  flocculent  tissue  which  covers  the  placenta 
at  the  third  or  fourth  month  of  pregnancy  does  not  exist  in  the  first,  and  as  from 
the  fifth  to  the  seventh  month  it  is  changed  into  a real  cellular  tissue,  to  form  the 
uterine  portion  of  the  placenta,  into  which  the  vessels  of  the  fetus  open  with  the 
uterine  veins,  we  must  consider  it  a tissue  of  secondary  formation,  similar  to  the 
deciduous  membrane,  with  which  it  i*  continuous,  and  not  as  a part  or  appendage 
of  this  membrane.  F.  T. 


EMBRYOLOGY. 


501 


The  reflected  deciduous  membrane  particularly  is  thin  and  reticu- 
lated, and  it  is  much  thinner  than  the  chorion.  It  likewise  becomes 
much  thinner  ns  the  ovum  enlarges.  It  also  approaches  the  external 
deciduous  membrane,  to  which  it  is  finally  more  or  less  adherent. 

§ 2569.  The  external  deciduous  membrane  never  extends  beyond 
the  internal  orifice  of  the  uterus.  On  leaving  this  point  the  uterus  or 
the  neck  is  filled  only  with  a gelatinous  fluid. 

According  to  some  observers  the  external  deciduous  membrane  ex- 
tends to  a certain  extent  in  the  tubes,  especially  on  the  side  where  the 
yellow  body  is  formed, (1)  and  it  isopen  at  the  place  of  the  uterine 
orifices  of  the  tubes,  as  also  at  its  lower  part,  that  which  passes  on 
the  inner  orifice  of  the  uterus. (2)  Perhaps  these  openings  exist  at 
first,  but  the  membrane  seems  to  change  very  soon  into  a perfectly 
closed  sac,  since  the  lower  opening  does  not  exist  during  the  first 
month, (3)  and  the  upper'two  are  also  effaced  at  the  second. (4) 

§ 2570.  It  is  not  very  easy  to  explain  how  the  reflected  deciduous 
membrane  is  formed.  Most  probably  the  ovum,  or  the  fluid  from 
which  it  is  produced,  penetrates  into  the  substance  of  the  deciduous 
membrane,  which  is  always  very  soft  and  very  loose,  but  which  pre- 
sents these  characters  primitively,  the  spaces  resulting  from  them 
afterwards  close,  and  the  ovum  is  then  developed  in  the  cavity  of 
the  membrane. (5) 

This  theory  agrees  with  the  observations  from  which  it  has  been 
concluded  that  the  external  and  internal  deciduous  membranes  are  pri- 
mitively distinct,  that  the  external  appears  first,  on  leaving  the  base  of 
the  uterus,  as  a membrane  possessing  longitudinal  blood-vessels,  and 
consequently  composed  apparently  of  bands  which  have  the  same  di- 
rection, and  that  the  internal  is  developed  afterward,  on  leaving  the 
inner  face  of  the  preceding,  and  possesses  horizontal  vessels  : so  that 
the  ovum  on  arriving  at  the  uterus  falls  into  a cavity,  the  roof  and 
parietes  of  which  are  formed  by  the  external  deciduous  membrane, 
while  the  floor  is  constituted  by  the  reflected  deciduous  membrane. (6) 

(1)  J.  Hunter,  in  the  Trans,  for  the  improv.,  vol.  ii.  p.  67. 

(2)  G.  Hunter,  Loc.  cit.,  p.  77. 

(3)  J.  Hunter,  loc.  cit.,  p.  67. 

(4)  Lobstein,  Sur  la  nutrition  du  fœtus,  p.  4. 

(5)  Moreau  asserts  that  when  the  ovule  enters  the  uterus  through  the  Fallopian 
tube,  it  only  pushes  before  it  the  deciduous  membrane,  which  is  already  a little  or- 
ganized before  its  arrival  ; that  it  is  covered,  as  is  every  internal  viscus,  by  the 
serous  membrane  of  the  sphlancnic  cavity  in  which  it  is  situated;  that  this  keeps  it 
in  contact  with  that  portion  of  the  uterus  to  which  it  is  attached  ; that  it  is  reflected 
on  it  on  leaving  the  place  where  the  placenta  is  formed,  and  which  is  the  only  part 
not  covered  by  it  ; that  the  three  openings  admitted  by  Hunter  do  not  exist  : in  a 
word,  that  the  deciduous  membrane  is  arranged  exactly  like  the  serous  membranes. 
This  theory  is  more  probable  than  the  ancient,  and  has  been  developed  by  Velpeau, 
who  supports  it  by  the  observation  and  dissection  of  a dozen  human  ova.  F.  T. 

(6)  Burns,  Observations  on  the  formation  and  structure  of  the  human  ovum  ; in 
the  Edinb.  med.  and  surg.  Journal,  voL  ii.  p.  1-4. 


VOL.  III. 


64 


502 


DESCRIPTIVE  ANATOMY. 


At  least  it  follows  from  these  same  observations  that  the  ovum  is 
not  introduced  into  the  substance  of  the  deciduous  membrane  at  the 
same  period  as  when  this  membrane  is  developed  on  the  inner  face  of 
the  utevus,(l)  since  the  phenomena  mentioned  by  us  have  been  ob- 
served in  the  cases  where  the  ova  are  still  contained  in  the  tubes. (2) 

§ 2571.  Notwithstanding  its  early  appearance,  the  deciduous  mem- 
brane does  not  belong  to  the  fetus,  and  is  not  indispensable  for  its 
development,  since  it  also  forms  equally  in  the  uterus  in  cases  of  extra- 
uterine  fetation,  and  the  fetus  then  is  not  the  less  developed,  although 
destitute  of  it.  (3) 


B.  MEMBRANES  OF  THE  FETUS. 

§ 2572.  The  ovum,  on  the  contrary,  includes  other  parts  which  are 
essentially  connected  with  the  formation  of  the  fetus.  These  parts  are 
the  chorion,  the  amnios,  the  umbilical  vesicle,  and  the  allantoid  mem- 
brane, which  we  proceed  to  describe,  without  regard  to  the  order  in 
which  they  form,  nor  the  part  they  take  in  the  special  vitality  of  the 
fetus. 

I.  CHORION. 


§ 2573.  The  chorion  ( chorion , s.  chorion  pellucidum,  s.  JYI.  vascu- 
losa,  s.  extima ),  the  most  external  of  the  special  membranes  of  the 
ovum,  is  thin,  transparent,  and  villous  on  its  two  faces,  particularly 
the  external.  The  villosities  of  this  latter  are  much  longer  than  those 
of  the  internal  and  ramify. 

The  external  villosities  are  masses  of  vessels,  the  trunks  of  which 
unite  to  form  the  umbilical  vessels. 

These  vessels  are  at  first  single,  but  more  or  less  prominent  at  in- 
tervals like  varices,  and  are  composed  only  of  veins. (4) 

Notwithstanding  its  thinness  and  transparency,  the  chorion  is  formed 
of  two  layers,  an  internal  and  an  external,  between  which  wind  small 
vascular  trunks  communicating  with  the  villosities,  and  which  arise 
from  them. (5) 

(1)  Hunter,  loc.  cit.,  p.  81. 

(2)  Burns,  loc.  cit.,  p.  3. 

(3)  Chaussier,  in  the  Bull,  de  la  fac.  de  Paris,  1814,  no.  6,  vol.  iv.,  p.  137. 

(4)  Lobstein,  loc.  cit.,  p.  65. 

(5)  This  opinion,  admitted  by  Hewson,  Bojanus,  and  Dutrochet,  is  rejected  by 

Velpeau.  He  thinks  that  the  chorion  is  always  formed  by  a single  layer,  and  if  it 
is  cccisidered  to  be  formed  by  two,  it  is  only  because  rather  a thick  membranous  con- 
cretion forms  between  it  and  the  placenta  when  this  latter  is  developed,  which  may 
be  separated  into  several  layers.  As  the  placenta  is  developed  on  the  outside  of  the 
chorion,  the  same  anatomist  also  states  that  it  covers  the  fetal  face  of  this  organ,  and 
is  even  reflected  on  the  cord,  with  which  it  arrives  at  the  umbilicus,  where  it  blends/ 
with  the  skin  of  the  fetus.  F.  T. 


EMBRYOLOGY. 


503 


Its  external  face  is  united  with  the  internal  face  of  the  deciduous 
membrane,  and  by  the  internal  with  the  amnios. 

Although  there  may  be  on  its  external  face  only  a great  develop- 
ment of  vessels,  we  cannot,  however,  demonstrate  the  existence  of 
these  latter  in  its  substance.  In  fact  many  observers  have  admitted 
them,  and  even  very  recently  it  has  been  adduced  in  favor  of  their 
existence  that  the  deciduous  membrane  contains  so  many  of  them, 
because,  they  say,  these  last  must  penetrate  into  the  chorion  ; and 
the  vessels  of  the  deciduous  membrane  seem  to  us  to  have  with  those 
of  the  chorion  a relation  similar  to  that  between  the  vessels  of  the 
uterine  portion  and  those  of  the  fetal  portion  of  the  placenta,  and  in 
this  hypothesis  we  can  easily  conceive  of  the  great  vascularity  of  the 
deciduous  membrane. 

The  chorion  has  no  lymphatic  vessels  or  nerves. 

§ 2574.  Its  form  and  connections  vary  much  at  different  periods  of 
the  life  of  the  fetus.  It  is  proportionally  much  thicker  at  first  than  it 
is  subsequently:  it  is  thicker  than  even  the  anmios,  but  gradually 
becomes  thinner. 

At  this  period  also  its  structure  and  thickness  are  uniform  in  every 
part. 

Its  external  face  is  villous  in  every  part,  and  these  villosities  are 
at  first  longer  than  they  are  afterward  and  in  the  second  month  are 
tortuous  and  proportionally  longer  than  before..  But  after  the  third 
month  these  villosities  gradually  disappear  in  most  of  its  extent,  usually 
from  below  upward,  so  that  the  outer  face  of  the  membrane  is  finally 
almost  smooth,  and  the  portion  which  surrounds  the  insertion  of  the 
umbilical  cord  is  the  only  one  where  we  still  observe  the  villosities 
compactly  arranged,  and  uniting  to  form  the  cord. 

This  place  forms  with  the  deciduous  membrane  a rounded  mass, 
which  in  the  full-grown  fetus  occupies  about  the  third  of  the  circum- 
ference of  the  ovum,  and  is  termed  the  placenta. 

The  chorion,  which  forms  its  inner  face,  is  much  thicker  there  than 
in  other  parts. 

At  first  this  membrane  is  united  to  the  deciduous  membrane  more 
loosely  than  it  is  subsequently  ; but  it  is  gradually  attached  to  it  so 
intimately  that  they  are  separated  with  difficulty,  particularly  on  the 
circumference  of  the  placenta,  where  the  union  occurs  by  numerous 
filaments,  remnants  of  vascular  villosities,  with  which  its  whole  sur- 
face is  at  first  covered. 


II.  AMNIOS. 

§ 2575.  The  amnios  ( amnion , s.  tunica  ovi  intima ) is  a very  thin 
and  transparent  membrane,  which  directly  envelops  the  fetus.  Its  ex- 
ternal face  adheres  but  feebly  to  the  chorion,  except  where  it  covers 


504 


DESCRIPTIVE  ANATOMY, 


the  inner  face  of  the  placenta  : the  internal,  on  the  contrary,  is  loose. 
These  two  faces  are  perfectly  smooth,  excepting  always  some  very 
loose  cellular  tissue  which  covers  the  external. 

Often  and  perhaps  even  always  during  the  early  periods  of  preg- 
nancy, this  membrane  is  more  or  less  separated  from  the  chorion,  which 
is  much  more  extensive,  and  between  them  is  a fluid  termed  the  false 
waters  of  the  amnios  ( liquor  amnii  spurius ).  But  this  liquid  disap- 
pears early,  at  the  second  montb,(l)  when  the  two  membranes  touch, 
although  they  are  sometimes  separated  at  the  fourth  and  fifth 
months. (2) 

The  amnios  is  reflected  on  itself  at  the  origin  of  the  umbilical  cord, 
covers  the  umbilical  vessels,  of  which  it  forms  the  external  envelope 
on  the  sheath,  and  extends  to  the  anterior  face  of  the  abdomen,  where 
it  is  continuous  with  the  projecting  portion  of  the  skin  of  this  region 
which  forms  the  umbilicus. 

As  yet  neither  blood  vessels  nor  nerves  have  been  found  in  the  am- 
nion, although  very  probably  the  substance  which  serves  to  unite  it 
with  the  chorion  contains  the  passages  through  which  the  nutritious 
and  secretory  fluid  penetrates  to  it. 

§ 2576.  This  membrane  contains  a liquid  termed  the  waters  of  the 
amnios  ( liquor  amnii), (3)  which  varies  in  several  respects  at  different 
periods  of  the  life  of  the  fetus. 

In  regard  to  its  physical  qualities  it  is  limpid  and  more  or  less  trans- 
parent in  the  early  periods  of  pregnancy  ; but  at  the  end  it  becomes 
turbid  and  more  or  less  flocculent.  It  is  also  at  first  thinner  and  less 
viscous. 

It  has  a strong  odor,  analogous  to  semen.  Its  taste  is  slightly 
saltish. 

It  contains  a considerable  number  of  globules. 

Its  specific  gravity  is  a little  less  than  that  of  water. 

Its  absolute  and  relative  quantities  vary  at  different  periods  of  preg- 
nancy. The  nearer  the  fetus  is  to  its  period  of  formation,  the  more 
abundant  proportionally  the  waters  of  the  amnios. 


(1)  Hunter,  p.  67. 

(2)  Lobstein,  p.  23-24. 

(3)  Franck,  De  liquore  amnii,  Gottingen,  1764. — F.  A.  Koenig,  De  aquis  ex  utero 
gravidarum  et  parturientium  profluentibus,  Halle,  1769. — J.  P.  Hettler,  De  liquoris 
amnii  natura  ac  indole,  Giessen,  1776. — H.  Van  den  Bosch,  De  nalurâ  ét  utilitale 
liquoris  amnii,  Utrecht,  1792. — P.  Scheel,  Diss.  de  liquoris  amnii  arteriæ  aspcrœ 
fœtuum  humanorum  naturâ  et  usu,  cui  adjeclus  est  appendix  sistens  gencraliora 
qucedam  de  liquore  amnii,  Copenhagen,  1799. — Bunivaand  Vauquelin,  Expériences 
sur  les  eaux  de  V amnios  ; in  the  Ann.  de  chimie,  vol.  xxxiii.,  and  Mém.  de  la  soc. 
méd.  d’ém.,  vol.  iii.  p.  229. — F.  F.  Reuss  and  F.  A.  F.mmert,  Chemische  Untersu- 
chung des  Fruchtwassers  aus  dem  zeitigen  Ei  und  der  käsigen  Materie  auf  der 
Haut  der  neugebornen  Kinder:  in  Osiander,  Annalen , Gottingen,  1801,  vo).  ii.  p. 
107. — G.  Egeling,  De  liquore  amnii,  nee  non  positiones  mcdici  argumerti,  Leyden, 
1813. — G.  F.  Fuckel,  De  liquoris  amnii  in  fœtus  corporis  superficial!  pressions , Mar- 
burg, 1819. 


EMBRYOLOGY. 


505 


About  the  middle  of  gestation  their  weight  nearly  equals  that  of  the 
fetus. 

From  this  period  they  gradually  diminish,  so  that  even  when  the 
fetus  is  delivered  without  breaking  the  membranes,  they  do  not  weigh 
more  than  a pound,  and  in  common  parturition  not  more  than  eight 
ounces. 

Their  absolute  like  their  relative  quantity  increases  at  first,  but  after- 
wards diminishes.  Thus,  for  instance,  we  find  only  thirty-six  ounces 
from  the  third  to  the  fourth  month. 

In  regard  to  chemical  composition  it  is  to  be  regretted  that  the 
waters  of  the  amnios  in  the  female  have  not  yet  been  analyzed,  nor 
comparative  experiments  made,  which  however  are  not  difficult,  in 
animals  at  different  periods  of  gestation.  All  those  we  possess  were 
made  on  the  waters  received  at  the  moment  of  parturition,  that  is,  in 
the  latter  periods  of  pregnancy. 

According  to  Scheel  the  waters  of  the  amnios  contain  free  oxygen  ; 
but  the  analyses  of  it  made  since(l)  have  not  confirmed  this  asser- 
tion.^) We  find  in  it  no  traces  of  loose  alkali. 

The  fluid  portion  is  composed  of  a considerable  quantity  of  water,  a 
little  albumen,  a still  smaller  proportion  of  gelatine,  of  the  hydrochlo- 
rates of  ammonia  and  soda,  and  of  phosphate  of  lime.  Heat,  alcohol, 
and  acids  do  not  change. it,  or  but  very  slightly. 

The  fîocculæ  are  very  similar  to  the  mucus  of  the  mucous  mem- 
branes.(3) 

Some  think  that  the  waters  of  the  amnios  are  formed  by  the  fetus 
and  others  by  the  mother.  The  first  represent  it  as  an  excretion, 
and  the  second  as  a nutritious  substance. 

Among  the  first  some  think  it  comes  from  the  urine  of  the  fetus,  and 
others  that  it  is  exhaled  by  the  skin. 

Many(4)  suppose  that  its  composition  is  mixed,  especially  in  the 
latter  periods  of  pregnancy,  that  it  is  formed  partly  of  the  excretion  of 
the  fetus,  partly  also  by  a nutritious  substance. 

The  most  probable  opinion  is,  that  the  waters  of  the  amnios  are 
secreted  at  least  in  great  part  by  the  vessels  of  the  mother,  although 
at  the  end  of  pregnancy  they  are  furnished  partly  by  the  fetus.  We 
have  been  led  to  this  opinion  because  it  seems  infinitely  probable  that 
this  liquid  serves  for  the  nutrition  of  the  fetus.  In  fact  : 

1st.  As  it  seems  to  contain  more  nutritious  substance  than  during 
the  first  periods,  because  more  coagulum  is  produced  by  heat  and  al- 

(1)  Lassaigne  (Sur  V existence  d’un  gaz  respirable  dans  les  eaux  de  l’ amnios  ; in 

(he  Archiv,  gên.  de  Méd.,  vol.  ii.  p.  308)  has  found  in  the  amniotic  fluid  of  the  sow 
4.130ths.  of  a gas  similar  to  the  atmospheric  air,  as  it  was  composed  of  azote  98.3, 
and  of  oxygen  21.7.  F.  T. 

(2)  Van  Doeveren,  Obs.  acad.,  c.  vii.  p.  103. 

(3)  Emnaert,  loc.  cit.,  p.  116. 

(4)  Emmert,  p.  121. 


506 


DESCRIPTIVE  ANATOMY. 


cohol,(l)  we  can  explain  this  difference  by  admitting  that  the  nutri- 
tious substance  has  been  absorbed  at  first,  and  that  when  it  is  less 
abundant  it  has  been  replaced  by  another  mode  of  nutrition. 

2d.  The  waters  of  the  amnios  are  probably  absorbed  by  the  skin  ; 
for  after  tying  a ligature  around  the  limbs  of  a fetus  plunged  into  this 
liquid,  the  sub-cutaneous  lymphatics  soon  swelled,  while  those  of  the 
limbs  which  were  not  tied  were  empty. (2)  Secondly,  fetuses  have 
been  born  with  the  mouth  closed,  and  with  an  umbilical  cord  entirely 
separated  from  the  placenta,  closed  and  rounded  at  its  loose  extre- 
mity.^) 

3d.  The  amniotic  fluid  also  penetrates  through  the  mouth,  since  it 
has  been  found  in  the  stomach,  esophagus,  cavity  of  the  tympanum, 
and  trachea,  where  it  has  been  easily  recognized  both  by  its  physical 
properties,  (4)  as  by  the  silky  «hairs  of  the  child,  and  also  the  meco- 
nium.(5) 

4th.  Correct  observations  teach  us  that  the  fetus  inspires  and  swal- 
lows, by  which  the  waters  of  the  amnios  penetrate  into  the  digestive 
and  air  passages.(6) 

5th.  Animals  newly  born  have  been  nourished  for  several  weeks  by 
keeping  them  in  the  waters  of  the  amnios. (7) 

But  besides  these  uses  relative  to  nutrition,  the  waters  of  the  amnios 
fulfill  other  functions  which  contribute  directly  or  indirectly  to  preserve 
the  fetus  : 

1st.  They  preserve  it  from  all  commotion  and  compression. 

2d.  They  keep  up  the  normal  distention  of  the  womb. 

3d.  They  connect  the  ovum  and  the  uterus  most  intimately. 

4th.  They  moderate  the  pressure  of  the  fetus  on  the  uterus. 

But  they  do  not  serve,  as  has  been  said,  to  prevent  the  obliteration 
of  the  openings  and  the  cavities  of  the  body  :(8)  first,  because  we  not 
unfrequently  find  such  anomalies  ; second,  because  the  mucous  mem- 
branes have  no  tendency  to  adhere,  at  least  unless  alterations  in  tex- 
ture supervene  in  them.  The  observations  of  abnormal  anuses,  which 
continued  open  for  many  years,  proves  also  that  these  secrete  fluids 
enough  to  prevent  the  union  of  their  surfaces. 

The  waters  of  the  amnios  are  useful  also  in  parturition,  because 
they  dilate  the  orifice  of  the  uterus,  and  lubricate  the  external  organs 
of  generation. 

(1)  Osiander,  Annalen , vol.  i.  pt.  i.  p.  190-200.— Lobstein,  loc.  cit.,  p.  103.  We  have 
always  observed  this  in  the  fetuses  of  the  ewe. 

(2)  Brug-mans,  in  Van  den  Bosch,  loc.  cit.,  p.  466, 467. 

(3)  Ibid. 

(4)  Winslow,  Herlioldt,  Rafn,  Abildgaard,  Scheel;  in  Scheel,  loc.  cit.,  p.  12. 

(5)  Osiander,  Handbuck  der  Entbindungskunde,  vol.  i.  p.  237. 

(6)  Winslow,  in  Scheel,  loc.  cit.,  p.  12. — Bedard,  in  the  Bull.  <le  la  fac.  de  Paris, 
1813,  no.  6-8. 

(7)  Weydlich,  in  Pohl,  Embryochemia,  Erlangen,  1806,  5 12. 

(8)  Lucæ,  in  Fuckel,  p.  10. 


EMBRYOLOGY, 


507 


III.  PLACENTA  AND  UMBILICAL  CORD, 


A.  PLACENTA. 

§ 2577.  The  placenta(l)  is  generally  a rounded,  oblong,  soft,  but 
solid  mass,  particularly  at  its  circumference,  and  is  composed  of  the  cho- 
rion  and  the  deciduous  membrane.  It  is  the  most  vascular  part  of  the 
ovum,  that  by  which  it  is  attached  most  intimately  to  the  uterus. 

This  body  is  generally  eight  inches  long  in  its  greatest  diameter,  six 
in  the  smallest,  and  one  thick  ; but  it  gradually  becomes  thinner  to- 
wards the  circumference.  Its  thickest  portion  is  where  the  umbilical 
cord  is  detached  from  it.  It  is  generally  inserted,  especially  in  the  first 
pregnancy,  at  the  upper  and  posterior  part  of  the  uterus,  a little  to  the 
right.  None  of  the  mechanical  explanations  of  this  phenomenon  are 
satisfactory.(2) 

The  placenta  is  composed  of  a considerable  number  of  lobes  ( colyle - 
dones ),  which  vary  in  size,  and  are  rounded  and  irregular  in  form  ; 
they  are  particularly  apparent  on  its  outer  or  uterine  face,  and  render 
it  very  uneven. 

About  the  period  when  the  fetus  is  full-grown,  it  is  covered  at  its 
outer  face  by  a layer  very  similar  to  the  deciduous  membrane,  which 
extends  not  merely  from  one  lobe  to  another,  but  penetrates  between 
them  and  unites  very  intimately  with  the  vessels  of  the  placenta. 
These  last  communicate  with  those  of  the  uterus.  Between  them  and 
the  placenta  are  very  large  veins.  We  remark  particularly  on  the 
circumference  of  the  placenta  a circular  vein,  into  which  several  veins 
of  the  deciduous  membrane  open. 

Although  this  layer  is  similar  in  structure  to  the  deciduous  mem- 
brane, it  seems  however  to  form  afterward,  since  the  portion  of  this 
latter  which  corresponds  to  the  placenta  disappears  soon  after  its  union 
with  the  uterus,  and  the  layer  in  question  exists  only  during  the  latter 
half  of  pregnancy. (3) 

The  inner  face  of  the  placenta  is  smooth  and  formed  by  the  chorion, 
which  is  thicker  there  than  in  any  other  part,  and  the  amnios  covers 
also  its  inner  face. 

We  remark  in  it  the  largest  of  the  branches  and  trunks  of  the  three 
umbilical  vessels  which  unite  the  body  of  the  fetus  with  the  mem- 
branes of  the  ovum. 

The  placenta  grows  constantly  and  absolutely  after  it  is  first 
formed  ; but  it  diminishes  in  proportion  to  the  fetus  and  the  other  parts 


(1)  G.  Munnibs  van  Cleef,  De  usu  placentae  humanae  comparatione  ejusdem  cum 
animalium  placentis  illustrait),  Utrecht,  1819. 

(2)  B.  F.  Osiander,  De  causa  insertionis  placentae  in  uteri  oriflcium  ex  novis 
circa  generationem  humanam  observationibus  et  hypothesibus  declaratâ,  Gottingen, 

(3)  Wrisberg,  Descript,  ovi  et  secund.,  § 183.  Lobstein,  loc.  cit.,  p.  58. 


50S 


rr.scuiPTivE  anatomy. 


of  the  ovum,  since  the  vessels  of  the  chorion  are  mostly’and  gradually 
obliterated.  Even  a part  of  those  of  the  placenta  gradually  close,  and 
then  appear  so  many  cords  filled  here  and  there  with  phosphate  of 
lime,  particularly  towards  the  upper  face  of  the  organ.  This  deposit 
occurs  also  out  of  the  vessels.  It  is  a sign  of  maturity,  of  old  age,  of 
the  mortification  of  placenta,  and  it  is  therefore  observed  only  when 
the  latter  is  about  to  be  detached. 

The  maturity  of  the  placenta  is  indicated  by  its  receiving  fewer 
vessels  ; it  becomes  dryer,  and  even  diminishes  in  its  mass  and 
size,(l)  although  these  changes  are  much  less  evident  in  the  female 
than  in  the  females  of  animals. (2)  We  must  then  consider  them  as  a 
commencement  of  separation  between  the  organism  of  the  child  and 
that  of  the  mother,  as  a prelude  to  parturition. 

E.  UMBILICAL  CORD. 

§ 2578.  The  umbilical  cord  (funiculus  umbilicalis ) is  composed  at 
least  of  the  following  parts  during  all  of  fetal  existence. 

1st.  The  umbilical  vein  and  two  arteries. 

2d.  A soft,  semi-fluid,  and  gelatinous  substance,  which  surrounds 
these  vessels,  and  is  termed  the  gelatine  of  Wharton  ( gelatina  Whar- 
toniana) . 

3d.  The  urachus. 

4th.  The  umbilical  sheath  ( vagina  umbilicalis),  which  surrounds  all 
these  parts,  and  which  proceeds  from  the  amnios. 

It  also  contains  during  the  early  periods,  and  particularly  until  the 
third  month  : 

5th.  A portion  of  the  intestinal  canal,  which  is  much  larger  the 
younger  the  fetus  is. 

6th.  The  whole  or  a part  of  the  umbilical  vesicle. 

7th.  The  omphalo-mesenteric  vessels. 

Hence  why  it  is  then  much  larger  than  it  is  subsequently. 

At  first  until  the  second  month,  sometimes  even  later  than  this,  but 
then  an  anomaly  exists,  the  umbilical  vesicles  are  straight.  They 
gradually  become  more  or  less  tortuous,  and  the  cord  also  assumes 
this  appearance,  the  more  so  as  its  caliber  also  diminishes.  It  is  cu- 
rious that  these  inflexions  generally  take  place  in  the  same  direction, 
from  left  to  right,  which  occurs  nine  times  to  one,  judging  from  our 
observations. 

The  gelatine  of  Wharton  varies  in  quantity.  Hence  the  difference 
between  fat  and  lean  cords. 

(1)  Lobstcin,  loc.cit.,y>.  141,  142. 

(2)  Joerg,  Leber  die  Zeugung,  p.  220. 


EMBRYOLOGY. 


50D 


We  may  inject  this  gelatinous  substance(l)  with  mercury  by  com- 
pressing it  a long  time  ; but  we  cannot  conclude  certainly  from  this 
that  it  receives  special  vessels  for  transmitting  a fluid  from  the  placenta 
into  the  body  of  the  fetus.  We  can  at  most  conclude  from  this  expe- 
riment that  the  gelatine  of  Wharton  is  composed  of  tunnels  adapted 
one  to  another,  formed  by  cellular  tissue,  and  containing  a substance 
in  motion  which  probably  serves  to  nourish  the  fetus. (2)  Although 
different  ancient  and  modern  anatomists  assert  they  have  discovered 
some  lymphatic  vessels  in  the  umbilical  cord, (3)  neither  Lobstein  nor 
myself(4)  have  perceived  them,  notwithstanding  all  our  researches  on 
this  subject. 

The  umbilical  sheath  envelops  the  parts  which  form  the  cord,  but 
not  tightly.  It  differs  more  from  the  skin  of  the  fetus  the  older  the 
fetus  is. 

We  have  not  been  able  to  satisfy  ourselves  of  the  existence  of  nerves 
in  the  umbilical  cord, (5)  and  we  therefore  do  not  admit  them. (6) 

§ 2579.  The  umbilical  cord  does  not  generally  arise  from  the  centre 
of  the  placenta,  but  is  inserted  a greater  or  less  distance  from  its  edge. 
It  is  attached  to  the  anterior  face  of  the  abdomen,  as  much  lower,  the 
younger  the  fetus  is,  and  on  leaving  this  part  its  constituent  portions 
separate. 

It  varies  in  size  and  length  at  different  periods  of  fetal  existence. 

At  first  and  until  the  end  of  the  first  month  it  does  not  exist,  and  the 
fetus  rests  directly  on  the  amnios. 

When  it  once  begins  to  appear,  it  extends  continually  until  the  fetus 
is  matured,  so  that  it  is  generally  about  two  feet  in  length  at  this  time, 
and  hence  nearly  as  long  as  the  full-grown  fetus. 

We  must  however  remark  that  these  two  periods  are  generally  se- 
parated by  a third,  during  which  the  umbilical  cord  is  proportionally 
longer,  and  exceeds  more  or  less  that  of  the  fetus  ; this  occurs  at  least 
from  the  end  of  the  second  to  the  end  of  the  sixth  month. 

At  the  end  of  pregnancy,  however,  the  cord  is  from  one  to  two  feet 
long. 

§ 2580.  The  placenta  and  the  umbilical  cord  establish  the  commu- 
nication between  the  child  and  the  mother.  The  first  is  essentially 
composed  of  two  different  parts,  the  fetal  and  the  uterine  portion. 


(1)  Uttini,  Sur  les  vaisseaux  absorbans  du  placenta;  in  the  Mem.  dell'  inst.  naz • 
ital.,  vol.  i. 

(2)  Lobstein,  loc.  cit.,  p.  38. 

(3)  Michaelis,  Observationes  circa  placentce  ac  funiculi  umbilicalis  vasa  absorben- 
tia,  Gottingen,  1790. 

(4)  Loc.  cit , p.  84. 

(5)  Chaussier  and  Ribes  assert  that  they  have  followed  the  filaments  of  the  gan- 

glionnary  nerves  of  the  fetus  along  the  umbilical  vessels  into  the  placenta.  (Chaus- 
sier, Expériences  nouvelles  sur  le  digestion , et’remarques  ace  sujet;  in  the  Journ. 
univ.  des  sc.  méd.,  vol.  i.  p.  233.)  F-  T. 

(6)  E.  F.  Durr,  Diss.  sistens  funiculum  umbilicalem  nervis  carere,  Tubingen, 
1815. — L.  S.  Rieck,  Utrum  funiculus  umbilicalis  nervis  polleat,  aut  careat,  Tubin- 
gen, 1816. 

Vol.  III. 


65 


510 


DESCRIPTIVE  ANATOMY. 


The  fetal  portion  is  formed  by  ramifications  of  the  umbilical  vessels 
and  by  the  chorion  ; the  uterine  by  the  prolongations  of  the  uterine 
vessels  and  by  the  deciduous  membrane.  These  two  portions  are 
united  much  more  intimately  the  older  the  fetus  is  ; but  their  respective 
vessels  always  remain  separate,  so  that  the  arteries  and  veins  of  the 
uterine  portion  communicate  directly,  as  do  those  of  the  fetal  placenta. 
Hence  why  injections  of  the  uterine  vessels,  even  when  most  success- 
ful, fill  only  the  uterine  placenta,  while  those  through  the  umbilical 
vessels  fill  only  the  fetal  portion.  Hence  also  when  we  inject  the 
placenta  detached  from  the  body,  or  when  it  is  not  separated  from  the 
body  of  the  living  infant,  so  that  the  blood  circulates  uninterruptedly 
within  it,  there  is  no  dribbling  of  blood  from  its  loose  surface.  Hence 
the  pulses  of  the  mother  and  the  umbilical  cord  are  not  isochronous. 

This  explains  why  children  born  without  the  rupture  of  their  en- 
velops can  live  a greater  or  less  length  of  time,  the  circulation  conti- 
nuing perfectly/ 1 ) and  probably  only  the  change  of  temperature 
obliges  us  to  open  all  the  envelops,  although  Wrisberg  has  prolonged 
the  experiment  for  nine  minutes,  and  Osiander  for  a quarter  of  an  hour 

The  same  fact  explains  why  the  cord,  which  remains  for  a long 
time  in  communication  with  the  mother,  after  being  separated  from  the 
body  of  the  fetus,  presents  only  a slight  running,  produced  by  the  small 
quantity  of  blood  contained  in  the  fetal  placenta. 

Finally  why  fetuses  can  survive  not  only  several  hours  when  their 
mother  perishes  from  hemorrhage,  but  can  also  preserve  more  or  less 
the  quantity  of  blood  they  generally  possess. 

§ 2581.  The  internal  or  fetal  placenta  is  composed  only  of  number- 
less ramifications  of  the  umbilical  arteries  and  vein,  surrounded  by  a 
vaginal  prolongation  of  the  chorion. 

The  arteries  and  the  veins  always  proceed  together  and  are  very 
much  curved,  like  the  trunks  ; their  final  ramifications  even  accom- 
pany each  other  constantly,  so  that  we  find  a small  artery  and  vein 
inclosed  in  the  same  vaginal  prolongaion  of  the  chorion. 

This  arrangement  however  occurs  only  in  the  latter  periods  of  preg- 
nancy ; for  during  the  early  stages,  the  vessels  of  the  fetal  placenta 
are  single  and  only  venous,  like  those  of  the  chorion  in  general. 

Besides  these  vessels,  we  find  in  the  placenta  white  tendinous  fila- 
ments which  arise  from  the  chorion,  enter  with  it  between  the  vascular 
trunks,  and  seem  to  be  only  obliterated  vessels,  which  are  often  half 
open  and  receive  injections. 

If  we  except  a considerable  and  oblique  anastomosis  between  the 
two  umbilical  arteries  at  the  base  of  the  placenta,  their  subordinate 
branches  do  not  communicate  from  one  lobe  to  another  within  this 
body.  There  is  no  other  anastomosis  between  the  branches  of  the 


(1)  In  the  experiments  of  Rœderer,  Wrisberg-,  and  Osiander  (Rœderer,  De  vi 
imaginationisinfœtumnegandâ,  Gottingen,  1756. — Wrisberg,  Obs.  de  struct,  ovi  ; 
in  the  Comment.,  vol.  i.  p.  618. — Osiander,  Annalen,  vol.  i.  pt.  i.  p.  27-28),  which  we 
have  repeated  with  the  same  results  on  dogs,  cats,  and  rabbits. 


EMBRYOLOGY 


511 


umbilical  vein.  On  the  contrary  the  arteries  and  veins  are  continuous 
by  proportionally  very  large  anastomoses. 

This  portion  of  the  placenta  is  proportionally  of  a very  loose  tissue  ; 
the  solidity  of  the  whole  mass  depends  on  that  of  the  next  portion. 

The  placenta  has  no  lymphatic  vessels  ; and  we  cannot  strictly  de- 
monstrate in  it  the  existence  of  nervous  filaments. 

§ 2582.  The  uterine  or  external  portion  of  the  placenta  is  much 
firmer  than  the  internal,  and  formed  by  the  membrane  similar  to  the 
deciduous  membrane  mentioned  by  us  above. 

This  membrane  covers  its  outer  face,  and  gives  it  a warty  appear- 
ance ; but  at  the  same  time  it  sends  internally  numerous  irregular 
prolongations,  which  penetrate  between  the  most  minute  ramifications 
of  the  umbilical  vessels,  with  which  they  form  alternate  elevations  and 
depressions. 

The  uterine  placenta,  like  the  whole  deciduous  membrane  which  cor- 
responds to  it,  is  formed  by  the  uterus,  and  its  vessels  are  prolongations 
of  the  uterine  vessels. 

The  arteries  are  very  tortuous,  and  the  diameter  of  the  largest  is 
nearly  a line.  The  veins,  which  are  less  tortuous,  but  which  go  ob- 
liquely to  the  placenta,  are  infinitely  broader.  Numerous  ramifica- 
tions of  veins  arise  from  the  deciduous  membrane,  which,  after  uniting 
in  trunks,  are  distributed  principally  on  the  edge  of  the  placenta. 

The  arteries  and  veins  communicate  in  the  uterine  placenta,  not  by 
anastomoses,  but  by  large  cellules  which  may  be  completely  filled, 
either  through  the  venous  or  arterial  trunks,  and  in  which  the  injection 
is  always  effused  before  passing  from  the  arteries  into  the  veins. 

These  cellules  should  be  considered  as  the  larger  openings  of  the 
vessels,  since  they  have  no  special  membranes,  and  form  also  large 
islands. 

§ 2583.  Notwithstanding  the  separation  of  the  two  circulations  in 
the  placenta,  there  is,  however,  between  its  two  constituent  portions 
and  their  vessels  a relation  of  mutual  action,  which  may  be  compared 
to  that  existing  between  the  air  and  the  blood  in  the  lungs,  or  between 
the  food  and  the  chyliferous  vessels  in  the  intestinal  canal. 

§ 2584.  The  uterine  placenta  is  only  a transient  production,  of 
which  the  uterus  is  in  great  part  disencumbered  when  the  fetal  pla- 
centa is  expelled,  although  a portion  of  the  deciduous  membrane  is 
not  perfectly  detached  from  the  inner  face  of  the  organ  until  several 
days  after  delivery. 

From  this  intimate  connection  between  the  uterine  placenta  and  the 
uterus,  although  the  section  of  the  cord  occasions  only  a slight  and  mo- 
mentary flow  of  blood,  as  we  have  said  above,  there  is,  on  the  con- 
trary, a greater  or  less  hemorrhage  from  the  rupture  of  its  vessels 
when  this  portion  is  detached,  which  is  soon  stopped  by  the  contrac- 
tion of  the  uterus. 


512 


DESCRIPTIVE  ANATOMY. 


IV.  UMBILICAL  VESICLE  AND  ALLANTOID  MEMBRANE. 

§ 2585.  Beside  the  membranes  hitherto  mentioned,  the  existence  of 
which  is  certain,  there  are  two  not  so  generally  admitted,  but  which 
are  similar  in  form  and  situation,  but  differ  from  the  two  preceding  in 
these  two  respects.  They  are  the  umbilical  vesicle  and  the  allantoid 
membrane.  These  two  membranes  do  not  form  superimposed  sacs 
and  envelops  of  the  fetus,  but  are  situated  between  the  chorion  and 
the  amnios.  They  do  not  continue  as  long  as  the  other  two  mem- 
branes, since  they  disappear,  or  at  least  become  inactive,  at  the  third 
month  of  pregnancy.  They  however  cannot  be  confounded  with  each 
other,  nor  can  we  suppose,  with  Lobstein,  for  instance, (1)  that  the 
umbilical  vesicle  of  man  is  the  allantoid  membrane  of  animals.  They 
are  two  entirely  different  organs,  which  coexist  in  most  vertebrated 
animals,  and  apparently  in  man  also. 

A.  UMBILICAL  VESICLE. 

§ 2586.  The  umbilical  vesicle  ( V.  umbilicalis , s.  saccus  vitellarius,  s. 
vesica  vitellaria,  s.  intestinalis , s.  processus  infundibuliformis , s.  hydatis 
funiculi)  is  constant.  Although  Osiander  has  asserted  that  it  should 
be  considered  as  a pathological  phenomenon,  occurring  only  in  mon- 
strosities, (2)  it  really  exists  in  every  ovum  during  the  early  months  of 
pregnancy. 

The  umbilical  vesicle  of  man  corresponds  neither  to  the  allantoid  mem- 
brane of  the  mammalia(3)  nor  of  birds  : for  the  arguments  drawn  from 
its  constancy,  transparency,  the  clear  and  limpid  fluid  which  fills  it, 
its  situation  between  the  other  membranes  of  the  ovum,  and  the  exist- 
ence of  vessels  on  its  surface,  adduced  in  favor  of  this  comparison,  are 
so  many  circumstances  which  demonstrate  still  better  its  analogy 
with  the  umbilical  vesicle  of  the  mammalia,  and  the  vitelline  sac  of 
birds. 

The  nature  of  its  vessels  and  its  connections  with  the  intestinal 
canal  also  support  this  analogy.  Besides  as  the  allantoid  membrane 
is  independent  of  it  in  the  mammalia  and  in  birds,  and  probably  also  in 
man,  Lobstein’s  opinion  cannot  be  admitted. 

§ 2587.  This  vesicle  is  as  much  larger  proportionally  as  the  fetus  is 
younger,  and  it  at  first  probably  exceeds  it  in  size  ; at  least  Lobstein  has 
figured  a case  of  this  kind, (4)  and  we  have  one  almost  similar  before 

U3. 

(1)  Loc.  cit.,  p.  44. 

(2)  Salzburg  med.  chir.  Zeitung , 1814. 

(3)  Lobstein,  loc.  cit.,  § 41-45. 

(4)  Loc.  cit.,  tab.  i. 


EMBRYOLOGY. 


513 


The  umbilical  vesicle  figured  by  Lobstein  is  the  largest  known. 
We  may  judge  from  it  that  the  organ  is  at  first  about  six  lines  in  dia- 
meter. 

The  largest  umbilical  vesicles  before  us  are  one  half  or  more  smaller  ; 
this  agrees  with  the  dimensions  given  by  most  authors, 

§ 2588.  This  organ  is  at  first  situated  directly  against  the  anterior 
face  of  the  fetus  ;(1)  but  it  removes  from  it  after  the  end  of  the  first 
month,  and  is  then  situated  on  the  outside  of  the  umbilical  sheath. 

§ 2589.  We  know  nothing  certain  in  regard  to  the  period  when  the 
umbilical  vesicle  appears.  Judging  from  analogy  with  birds,  as  it 
corresponds  to  the  vitelline  sac,  we  might  conclude  that  it  arises  be- 
fore all  other  parts  of  the  ovum,  and  on  this  account  it  has  even 
been  asserted  that  the  false  germs  are  umbilical  vesicles,  and  not  sacs 
formed  by  the  chorion  and  amnios,  as  is  generally  supposed.(2)  Al- 
though the  received  opinion  be  not  perhaps  applicable  to  all  cases, 
we  however  shall  continue  to  follow  it  until  the  contrary  is  proved  by 
positive  facts. 

According  to  Hunter, (3)  the  umbilical  vesicle  sometimes  continues 
to  the  end  of  pregnancy  ; but  it  is  not  larger  at  this  period  than  in  an 
ovum  of  two  or  three  months,  and  is  from  half  an  inch  to  an  inch  and 
a half  distant  from  the  insertion  of  the  umbilical  cord  in  the  placenta. 
We  regard  this  fact  as  very  rare,  having  found  it  only  twice  in  a great 
number  of  deliveries. 

§ 2590.  The  umbilical  vesicle  is  formed  by  rather  a thick  granular 
membrane,  which  does  not  tear  when  forcibly  distended  with  water. (4) 
It  gradually  collapses,  is  covered  with  wrinkles,  and  becomes  opaque. 
The  omphalo-mesenteric  vessels  are  distributed  in  it. 

It  contains  a whitish  fluid,  which  gradually  diminishes,  becomes 
thick,  and  finally  hardens. 

§ 2591.  We  have  treated  of  its  connections  with  the  fetus  at  some 
length  in  the  histoty  of  the  development  of  the  intestinal  canal,  and  we 
have  attempted  to  demonstrate  that  very  probably  it  communicates 
with  the  ileon  by  the  omphalo-mesenteric  vessels  and  by  a canal. 

§ 2592.  Its  constancy,  its  great  size  in  the  commencement,  and  its 
probable  existence  before  other  parts,  prove  that  it  takes  a very  im- 
portant part  in  the  development  of  the  fetus. 

Judging  from  what  occurs  in  birds,  its  contents  pass  into  the  body 
of  the  fetus,  and  serve  for  nourishment,  like  yolk  to  the  chicken.  It 
however  disappears  sooner  than  the  vitelline  sac. 

§ 2593.  Opinions  are  still  divided  on  the  question  whether  there  is, 
as  in  all  the  other  mammalia,  an  allantoid  membrane  ( allantois , s, 

(1)  Lobstein,  loc.  cit.,  p.  46. 

(2)  Oken,  Beyträge,  pt.  ii.  p.  83. 

(3)  Anatomie  des  schwängern  Uterus,  p.  68, 

(4)  Lobstein,  toc.  cit.,  p.  43. 


su 


DESCRIPTIVE  ANATOMY. 


membrann  media, )(\)  which  communicates  with  the  bladder  through 
the  urachus. 

Needham, (2)  Hale, (3)  Bidloo,(4)  Hoboken, (5)  de  Graaf,(6) 
Littré, (7)  Rouhault,(8)  Neufville,(9)  Haller, (10)  Emmert,(ll) 
Joerg,(12)  Dutrochet.,(13)  and  Cuvier, (14)  admit  it.  Paré, (15)  Har- 
vey,(16)  Ruysch.(17)  Heister, (18)  Troortwyk,(19)  Neu, (20)  Albi- 
nus,(21)  A.  Monro, (22)  Danz,(23)  and  Hunter, (24)  deny  it.  Al- 
though some  of  the  numerous  facts  adduced  to  support  it  are  false, 
and  others  but  slightly  conclusive,  we  however  agree  with  the  first  of 
these  two  opinions,  because  we  have  found  in  a human  fetus  about 
four  weeks  old,  between  the  chorion  and  the  amnios,  and  independent 
of  the  umbilical  vesicle,  a larger  pouch,  with  thin  parietes,  collapsed, 
and  containing  a limpid  fluid. (25)  We  have  seen  this  since. 

Its  existence  may  be  supported  : 

1st.  By  the  cases  where  we  have  found  in  the  other  membranes  a 
pouch  different  from  the  umbilical  vesicle.  In  fact  some  observations 
of  this  kind  are  very  suspicious  ; but  we  have  several  times  been  sa- 
tisfied of  the  existence  of  a delicate  layer,  differing  from  the  rest  of  the 
ovum,  which  first  forms  a close  vesicle  until  about  the  end  of  the  se- 
cond month  of  pregnancy,  and  which  afterward  appears  as  a thin 
lamina. 

2d.  By  the  space  between  the  amnios  and  the  chorion.  This  space 
is  greater  in  the  early  periods  than  afterward,  and  is  filled  by  a fluid 


(1)  R.  Hale,  The  human  allantoid  discovered  ; in  the  Phil,  trans.,  p.  270, — Sel- 
lius,  De  allantoide , Kiel,  1729. — C.  de  Neufville,  De  allantoide  humanâ,  Leyden, 
1736. — Haller,  De  allantoide,  1739. — J.  G.  Betschler,  Diss.  num  a fœtu  urina  secer » 
natur  et  sécréta  excernalur,  Berlin,  1820. 

(2)  De  formato  fœtu , c.  iii. 

(3)  Doc.  cit. 

(4)  Tab.  anat.,  58,  lit.  E. 

(5)  Anat.  secund.  hum.  rep.,  p.  428. 

(6)  De  mulier.  org.,  cap.  xv.  ; Opp.  omn.,  p.  283. 

(71  Mêm.  de  Paris,  1701,  p.  115. 

(9)  Osservaz.  anat. fis.,  Turin,  1724,  p,  21. 

(9)  Doc.  cit. 

(10)  Doc.  cit. 

(11)  Nachtrag  zu  den  beiden  Abhandlungen  über  das  Nabelblaschen  ; in  tha 
Archiv,  für  die  Physiologie,  vol.  x.  p.  373. 

(12)  Die  Zeugung,  p.  288.  Joerg  however  draws  hie  conclusions  solely  from  the 
space  often  existing  between  the  chorion  and  the  amnios. 

(13)  Doc.  cit. 

(14)  M.ém.  de  Mus.,  vol.  iii. 

(15)  Anat.  chir.,  1.  ii.  c.  xxxv. 

(16)  Exerc.  de  gener.  c.  de  memb.  et  humor. 

(17)  Thesaur.  3,  no.  57  ; th.  9,  no.  21. 

(18)  Eph.  nat.  curios,  cent.  II.,  obs.  190. 

SDe  utero  gravido  ; p.  iii.,  De  allantoide. 

De  diff.  fœt.  et  adulti,  p.  105. 

(21)  Annot.  acad.,  1.  i.  c.  xix.  p.  75. 

(22)  Essays  of  a soc.  of  Edinb.,  vol.  ii. 

(231  Doc.  cit.,  p.  i.  § 12. 

(24)  Anatomie  des  menschlichen  schwängern  Uterus,  p.  84. 

(25)  Deutsches  Archiv,  für  die  Physiologie , vol.  iii.  tab.  i.  fig.  2. 


EMBRYOLOGY. 


515 


which  is  sometimes  very  abundant  at  parturition,  and  which  forms 
what  is  termed  the  false  ivaters. 

3d.  By  the  analogy  with  other  animals. 

This  vesicle  has  always  very  thin  parietes,  which  are  more  delicate 
than  those  of  the  other  membranes. 

Tt  is  not  certain  that  it  communicates  at  any  period  with  the  ura- 
chus. Dutrochet  admits  this  communication,  but  has  never  observed 
it.  It  however  probably  exists,  at  least  in  the  early  periods  of  gesta- 
tion, either  from  analogy,  or  because  the  urachus  makes  part  of  the 
umbilical  cord,  or  finally  from  the  possibility  of  following  it  there  more 
or  less  to  the  placenta, (1)  of  introducing  into  it  a liquid, (2)  and  even 
of  demonstrating  within  it  an  immediate  connection  between  this  body 
and  the  allantoid  membrane. (3)  We  have  been  able  more  or  less 
easily  to  follow  the  urachus  in  almost  its  whole  length  at  every  period 
of  pregnancy,  and  even  to  fill  it  partially  wdth  mercury  : but  we  have 
never  been  able  to  prove  that  it  communicated  either  with  the  space 
between  the  two  proper  membranes,  or  with  the  allantoid  membrane. 

We  do  not  know  certainly  how  long  the  allantoid  membrane  exists. 

We  have  seldom  been  able  to  trace  it  evidently  in  the  latter  months 
of  pregnancy. 

§ 2594.  The  allantoid  membrane  is  generally  considered  as  the  re- 
servoir of  the  urine,  which  is  carried  to  it  by  the  urachus  from  the 
bladder. 

This  is  the  opinion  of  most  physiologists  and  physicians. 

Joerg  thinks  even  that  the  allantoid  membrane  itself  secretes 
urine, (4)  which  is  not  very  probable,  since  the  kidneys  exist,  and  are 
more  developed  than  at  subsequent  periods  of  life. 

Harvey, (5)  Lobstein,(6)  and  Oken,(7)  have  advanced  another  opi- 
nion. 

Harvey  maintains  that  the  liquid  of  the  allantoid  membrane  is  not 
urine,  but  a nutritious  fluid  : 

1st.  Because  it  exists  in  the  ova  where  there  is  no  fetus.(8) 

2d.  Because  it  is  abundant  when  the  organ  is  formed. (9) 

3d.  Because  the  allantoid  membrane  is  at  first  proportionally  and 
even  absolutely  much  larger  than  subsequently, (10)  while  it  is  ad- 
mitted that  the  secretion  of  the  urine  is  in  a direct  ratio  with  the  ad- 
vanced age  of  the  fetus. 


(1)  Albinus,  in  Neufville,  p.  42,  43. — Hunter,  loc.  cit.,  p.  45. — Cruikshank,  ibid. 

(2)  Noreen  and  Rœderer. — A.  Monro,  in  the  Edinb.  phys.  essays  and  obs.,  vol.  i. 
p.  485. — Ridley,  Obs.  med.  pr.,  London,  1703. 

(3)  Albinus,  in  Neufville,  p.  43.  But  this  undoubtedly  refers  to  the  umbilical 
vesicle. 

(4)  Zeugung , p.  298. 

(5)  De  gener.  anim.,  Amst.,  1662,  p.  364. 

(6)  Loc.  cit.,  p.  53. 

(7)  Bey  träge,  pt.  i.  p.  29. 

(8)  Harvey. 

(9)  Id. 

(10)  Lobstein,  p.  54. 


516 


DESCRIPTIVE  ANATOMY. 


4th.  Because  we  cannot  conceive  why  the  urinary  secretion  should 
be  the  most  important  function  in  the  fetus.(l) 

5th.  Because  the  allantoid  membrane  is  deficient  in  some  mamma- 
lia, and  it  is  very  improbable  that  the  fetuses  of  some  animals  should 
secrete  urine  and  others  not. (2) 

6th.  Because  it  is  very  difficult  in  the  nearly  perfect  fetus  of  the 
adult  to  pass  air  from  the  bladder  into  the  allantoid  membrane. (3) 

7th.  Because  the  fluid  would  not  be  excretory,  since  a considerable 
number  of  umbilical  veins  (absorbents)  are  distributed  in  the  enveloping 
membrane. (4) 

8th.  Because  the  fluid  differs  from  the  urine. (5) 

But  all  these  arguments  prove  nothing  against  the  old  opinion,  or  in 
favor  of  that  of  the  writers  who  adduce  them. 

1st.  The  existence  of  the  allantoid  membrane  and  its  fluid  without 
a fetus  proves  nothing,  and  that  considered  as  such  may  be  something 
else,  or  the  fetus  may  not  be  deficient. 

2d  and  3d.  The  size  of  the  allantoid  membrane  and  the  quantity  of 
its  fluid  during  the  early  period  of  gestation,  are  explained  very  well 
by  the  more  rapid  progress  of  all  the  formations  at  this  period,  and 
because  very  probably  the  other  excretions  do  not  take  place  then,  or 
at  least  but  slightly. 

4th.  The  size  of  the  allantoid  membrane  does  not  prove  that  the 
urinary  secretion  is  the  most  essential  of  all  the  functions,  but  only 
that  it  replaces  in  great  part  all  the  other  excretory  systems,  from  the 
simple  reason  that  the  products  of  the  action  of  these  latter  had  been 
in  contact  with  the  fetus  during  the  whole  of  pregnancy. 

5th.  This  fact  is  entirely  incorrect,  for  the  allantoid  membrane  is 
very  constant.  Farther  its  absence  might  possibly  be  compensated 
for  in  some  way. 

6th.  In  this  case  the  same  difficulty  exists  in  passing  air  from  the 
allantoid  membrane  into  the  bladder, (6)  while  it  is  very  easy  during 
the  early  periods  of  gestation,  as  we  have  more  than  once  proved.  It 
follows  then  at  most  from  this  fact,  that  the  quantity  of  urine  secreted 
gradually  diminishes,  and  collects  in  the  bladder. 

7th.  This  objection  rests  upon  confounding  the  allantoid  membrane 
with  the  chorion.  The  vessels  do  not  belong  to  it,  but  to  this  latter  ; 
at  least  they  do  not  absorb  within  it,  but  in  the  cavity  of  the  uterus. 

8th.  It  does  not  follow,  for  several  reasons,  from  the  fact  reported, 
that  the  liquid  was  not  urine. 

We  cannot  consider  the  allantoid  membrane  as  the  formative  mem- 
brane of  the  urinary  and  genital  apparatus,  or  of  the  bladder, (7)  for  it 

(1)  Id.,  ibid. 

(2)  Id.,  ibid. 

(3)  Oken,  p.  58. 

(4)  Harvey. 

(5)  Oken,  p.  39 


EMBRYOLOGY. 


517 


birds  it  arises  very  evidently  from  the  urinary  system,  and  does  no; 
exist  in  the  ova  of  the  batracia. 

The  bladder  is  not  formed  by  the  urachus  ;(1)  but  the  canal  corre- 
sponding to  the  bladder  and  urachus,  which  was  at  first  uniformly 
narrow,  enlarges  at  its  lower  part,  is  completely  developed  and  be- 
comes the  bladder,  while  the  upper  part,  which  is  not  developed  in  the 
same  manner,  remains  the  urachus. 

II.  ORIGIN  OF  THE  OVUM,  AND  THE  ORDER  IN  WHICH  ITS  PARTS  FORM. 

§ 2595.  It  is  extremely  difficult  to  determine  the  period  at  which 
the  ovum  first  appears.  Although  the  duration  of  pregnancy  is  ascer- 
tained with  certainty,  it  does  not  necessarily  follow  that  the  new  or- 
ganism always  begins  to  form  at  the  same  period,  for  the  development 
of  the  embryos  of  birds  proves  that  although  the  ova  are  all  matured 
at  the  same  period,  there  is,  however,  a great  difference  between  em- 
bryos of  the  same  brood  in  the  development  of  different  organs,  or  of 
the  whole  body. 

From  the  eighth  day  after  coition  a tendency  to  form  the  deciduous 
membrane,  and  also  the  fetal  portion  of  the  ovum, (2)  has  been  ob- 
served. 

From  the  rapidity  with  which  the  transitory  or  permanent  parts  of 
the  body  form  successively  in  the  superior  animals,  and  from  the  pro- 
portionally very  small  number  of  perfect  observations  on  the  develop- 
ment of  the  ovum  in  particular,  it  is  extremely  difficult  to  determine  if 
the  different  parts  of  this  latter,  described  in  the  preceding  article,  form 
at  the  same  time  or  at  different  periods,  and  also  the  order  of  their 
appearance,  and  their  part  in  the  formation  and  development  of  the 
fetus. 

Very  probably,  however,  the  deciduous  membrane  begins  to  form  at 
the  same  time  as  the  ovum,  or  the  fetal  portion  of  it,  since  we  observe 
the  changes  in  the  uterus,  connected  with  its  appearance,  very  early, 
even  before  the  latter  is  seen  there. 

Hitherto  physiologists  have  generally  considered  the  chorion  and 
the  amnios  as  the  most  essential  parts  of  the  ovum,  those  which  arise 
first  ; and  even  now  the  external  of  the  two  membranes  to  which  the 
least  advanced  ova  can  be  reduced  is  considered  the  chorion,  and  the 
internal  as  the  amnios. 

Analogy  with  the  development  of  animals  inferior  to  the  mammalia, 
however,  renders  it  very  probable  that  the  umbilical  vesicle  is  deve- 
loped the  first,  and  that  the  other  membranes  form  after  it,  since  in  the 
animals  mentioned,'  the  vitelline  sac,  which  corresponds  to  the  umbili- 
cal vesicle,  appears  long  before  all  other  parts  of  the  ovum,  which 
precede  only  the  body  of  the  fetus. 

(1)  Ibid.,  p.  290. 

(2)  Home,  Phil.  Irans.,  1817,  pt.  ii.  p.  256-261. 

66 


VOL.  III. 


518 


DESCRIPTIVE  ANATOMY. 


III.  FETUS. 

§ 2596.  It  is  very  difficult  to  determine  precisely  the  period  when 
the  human  fetus(l)  forms.  This  ought  not  to  surprise,  for  this  is  still 
more  uncertain  in  the  history  of  the  oviparous  animals  even,  notwith- 
standing the  greater  facilities  they  present  to  the  observer,  and  the 
numberless  observations  upon  them.  It  however  is  certain  that  a 
greater  or  less  length  of  time  elapses  after  coition,  followed  by  impreg- 
nation, before  the  ovum  becomes  visible. 

We  may  admit  generally  that  it  appears  in  the  second  week  after 
coition,  and  there  are  very  probably  greater  or  less  differences  in  this 
respect.  Haller’s(2)  opinion,  however,  that  the  fetus  does  not  become 
visible  till  the  end  of  the  third  week  does  not  seem  to  be  entirely  cor- 
rect, since  it  does  not  agree,  among  others,  with  Home’s  observation 
mentioned  in  the  preceding  article. 

I.  MODE  OF  ORIGIN» 

§ 2597.  The  problem  of  the  mode  of  origin  of  the  fetus  is  still  more 
difficult,  and  all  that  has  been  said  on  this  subject  is  reduced  almost  to 
hypothesis,  instead  of  observations  and  facts. 

It  is  certain,  however,  that  the  fetus  is  united  to  its  membranes  from 
the  first. 

The  contrary  opinion  that  it  arises  in  the  waters  of  the  amnios, 
without  any  adhesion,  cannot  be  sustained.  It  is  supported  by  the 
following  arguments  :(3) 

(1)  Beside  the  works  already  cited  in  the  course  of  this  book,  consult  also:  1st. 
On  the  form  and  structure  of  the  fetus: — Cas3ebohm,  Dc  differentia,  fœtus  et  adulti 
anatomiccï,  Halle,  1730. — C.  J.  Treu,  De  jlifferentiis  quibusdam  inter  hominem. 
nalumet  nascendum  intercedenlibus,  Nuremberg,  1736. — Hebenstreit,  Programma 
de  anatomc  hominis  reccns  noli,  Leipsic,  1739. — Treu,  Descriptio  et  delineatio  em- 
bryonum  humanorum  ; in  the  Comm.  Nor.,  1739. — J.  G.  Rœderer,  De  fœtuperfecio, 
Gottingen,  1750. — J.  A.  Langguth,  De  anatomice  embryonis  trium  cum  dvmidio 
mensium,  Wittembcrg,  1751. — J.  G.  Rœderer,  De  fœtu  observationes,  Gottingen, 
1758. — H.  A.  Wrisberg,  Descriptio  anatomice  embryonis  observationibus  illustrata, 
Gottingen,  1764. — A.  È.  Koelpin,  De  fœtus  et  adulti  différentiis,  Gripswald,  1764. — 
J.  F.  Dietz,  Differentia  fœtus  ab  adulto,  Giessen,  1770. — A.  and  F.  Rosslein,  Dediffe- 
rentiis  inter  fœtum  et  adultum , Strasburg,  1783. — Autenrieth,  Supplémenta  ad  his- 
toriam  embryonis  humani,  Tubingen,  1797. — S.  T.  Sœmmerring,  Icônes  embryonum, 
Frankfort,  1799. — 2d.  On  its  mode  of  existence: — Rose,  De  natv.râ  embryonis  hu- 
mani, Leipsic,  1774. — J.  Van  Solingen,  De  vitâfœtàs  propriâ , Utrecht,  1782. — A. 
Brendel,  De  nutritione  fœtîis  in  utero  materno,  Wittcmberg,  1704. — Treu,  De  chylosi 
fœtûs,  Altdorf,  1715. — Bernhardi,  De  nutritione  fœtus  in  utero,  Halle,  1732. — J.  de 
Diest,  An  sui  sanguinis  solus  opif ex  fœtus,  Paris,  1725. — A.  Nann,  Eversa  vasorum 
rubrorum  uteri  anastomosis  et  communicatio  cum  placenta,  Erford,  1751.— R. 
Forsten,  Q uœsliones  medicœ,  Leyden,  1774. — Scha  ffer,  De  commercio  fœtûs  cum 
■maire  per  nervös,  Erlangen,  1775. — Richard,  De  modo  nutritionis  fœtûs,  Erford, 
1783. — Stoy,  De  nexu  inter  matrem  et  fœtum,  Halle,  1786. 

(2)  El.  phys.,  vol.  viii.  p.  61. 

(3)  C.  F.  Burdach,  De  priinis  momcnlisformationis  fœtûs,  Königsberg,  1814. 


EMBRYOLOGY. 


519 


1st.  The  nervous  system,  which  forms  before  all  the  other  parts,  is 
never  united  with  the  ovum. 

2d.  A film  is  gradually  developed  in  the  midst  of  the  fluid  of  the 
amnios,  which  is  the  fetus. 

3d.  The  fetus  is  straight  originally,  although  it  is  the  general  opi- 
nion that  it  curves  from  the  moment  of  its  origin. 

All  these  arguments  are  easily  refuted. 

In  fact  the  part  first  formed  has  not  been  strictly  determined.  It 
seems  probable  to  us  that  the  rudiment  first  seen  is  the  common  base 
of  several  parts,  and  even  in  the  inferior  animals  one  organ,  and  in  the 
most  inferior  the  apparently  homogeneous  substance  of  their  .body  re- 
presents several  organs  at  the  same  time.  Secondly,  we  can  well 
conceive  that  the  nervous  syrstem  appearing  first,  it  is  primarily  con- 
nected with  the  envelops  of  the  ovum. 

The  second  argument  does  not  rest  upon  facts  ; and  we  do  not  see 
why  the  fetus  could  not  be  formed  straight  as  well  as  curved  from 
some  portion  of  the  ovum. 

Finally,  another  circumstance  also  exists  against  this  opinion,  viz. 
the  membrane  of  the  amnios  and  the  liquid  it  contains  certainly''  appear 
after  the  fetus  in  birds,  and  the  fetus  of  these  animals  is  connected  with 
the  ovum  at  its  first  appearance. 

The  same  is  true  doubtless  of  the  human  fetus.  It  is  developed 
“then  on  the  ovum,  and  at  the  expense  of  one  of  its  parts. 

Another  question  now  presents  itself  : At  the  expense  of  what  part 
of  the  ovum  is  it  developed,  and  how  does  this  development  occur? 

Judging  from  analogy  with  the  other  vertebrated  animals,  the  hu- 
man fetus  is  very  probably  developed  upon  the  umbilical  vesicle,  and 
at  its  expense.  But  analogy  alone  does  not  merely  favor  this  hypo- 
thesis, in  support  of  which  we  mayr  also  alledge  the  greater  considera- 
ble size  of  the  umbilical  vesicle  at  first,  and  the  position  of  the  lower 
part  of  the  fetus  directly  upon  this  pouch. 

II.  FORM. 

§ 2598.  After  its  origin  the  fetus  presents  an  almost  infinite  number 
of  degrees  in  its  form  and  structure,  the  most  general  of  which  have 
already  been  mentioned  in  the  introduction,  while-freating  of  the  eight 
laws  of  the  organic  formation,  or  in  descriptive  anatomy,  in  stating  in- 
regard  to  each  system  and  each  organ  the  peculiarities  which  charac- 
terize it  at  different  periods  of  its  development. 

The  body  of  the  fetus  is  longer  at  its  first  appearance  than  it  is  sub- 
sequently. 

The  portion  of  its  body  which  appears  first,  corresponds  almost  ex- 
clusively to  the  trunk  ; we  only'-  remark  at  its  upper  part  a small  pro- 
minence separated  from  the  rest  .by  a fissure,  which  is  by  no  means 
equal  in -thickness  to  the  central  part  of  the  body.  This  prominence 
is  the  rudiment  of  the  head. 


520 


DESCRIPTIVE  ANATOMY. 


As  yet  there  is  no  trace  of  extremities,  nor  of  the  other  prominences, 
particularly  of  the  nose,  the  ears,  and  the  genital  parts. 

The  fetus  has  then  the  form  of  a worm. 

It  is  entirely  or  almost  entirely  straight  ; \ve  only  remark  that  the 
dorsal  face  is  slightly  convex,  and  the  abdominal  slightly  concave. 

It  is  attached  to  the  inner  membrane  of  the  ovum  directly,  or  by  a 
very  short  umbilical  cord  at  its  lower  extremity,  or  by  the  part  of  its 
body  directly  above  this  extremity. 

When  the  umbilical  cord  is  inserted  above  the  lower  extremity  of 
the  body,  this  extremity  slightly  curves  from  behihd  forward,  in  the 
form  of  a tail. 

All  the  openings  which  afterward  exist  are  now  completely  closed. 

The  head  gradually  becomes  proportionally  large,  so  that  towards 
the  commencement  of  the  second  month  it  forms  nearly  half  of  the 
whole  body.  It  is  generally  smaller  before  and  after  this  period. 

The  body  of  the  fetus  curves  much  at  its  upper  and  lower- extremi- 
ties : the  head  is  continuous  with  the*  trunk  at  a right  angle,  and  its 
lower  portion,  which  corresponds  with  the  chin,  is  attached  only  to  the 
top  of  the  chest  ; the  trunk  is  perfectly  straight  ; there  is  no  trace  of 
the  neck  externally  until  the  end  of  the  second  month. 

Until  the  middle  of  the  third  month  the  lower  extremity  of  the  ver- 
tebral column  is  curved  from  behind  forward  and  from  below  upward, 
projects  below  the  anus,  and  represents  the  rudiment  of  a tail,  which 
is  at  first  very  long  ; this  gradually  shortens  and  finally  disappears 
entirety,  but  it  is  always  attached  by  its  inner  face. 

The  limbs  appear  in  the  fifth  week  of  pregnancy  : the  superior  ge- 
nerally a little  sooner  than  the  inferior.  They  then  have  the  form  of 
small  tubercles  terminated  by  a blunt  summit.  The  superior  are  si- 
tuated directly  below  the  head,  and  the  inferior  directly  before  the 
caudal  extremity.  Both  proceed  from  behind  forward,  but  a little  also 
from  within  outward,  on  account  of  the  greater  development  of  the 
abdominal  cavity.  Sometimes  also  the  superior  go  a little  from  above 
downward,  and  the  inferior  slightly  from  below  upward,  but  this  ar- 
rangement is  by  no  means  constant  ; they  often  also,  particularly  the 
inferior,  assume  an  entirety  opposite  arrangement. 

During  the  sixth  week,  and  until  the  seventh,  the  stump  which  first 
appeared  and  which  gradually  lengthened,  is  divided  into  a peripheri- 
cal  and  a central  segment  : these  segments  correspond  to  the  hand 
and  fore  arm,  to  the  foot  and  leg. 

One  or  two  weeks  afterward  a third  appears,  which  represents  the 
arm  and  the  thigh. 

The  segments  formed  last  are  much  shorter  than  those  which  ex- 
isted previousty,  although  the  contrary  is  true  when  the  fetus  is  per- 
fectly developed. 

About  the  period  when  the  stump  of  the  limb  begins  to  divide  into 
an  internal  and  an  external  part  the  latter  becomes  round,  and  enlarges 
at  its  loose  extremity,  and  a single  band-like  eminence  is  frequently 
developed  at  its  summit,  from  which  it  is  separated  by  a depression. 


EMBRYOLOGY. 


521 


Thi3  eminence  soon  gradually  divides  to  form  the  fingers,  which  are 
at  first  proportionally  short  and  thick,  and  which  until  the  third  month 
are  still  united  by  a thin  substance  similar  to  the  membrane  between 
the  toes  of  web-footed  animals,  or  the  bones  of  the  fins  in  fishes. 

This  uniting  substance,  this  thin  membrane,  gradually  disappears 
from  the  summit  to  the  base  of  the  fingers  and  toes. 

The  upper  limbs  appear  before  the  lower  ; they  also  pass  through 
all  their  successive  degrees  of  formation  more  rapidly  than  the  latter. 
They  are  for  a long  time  absolutely  larger,  so  that  at  five  years  of  age 
the  four  limbs  have  nearly  the  same  length. 

When  the  limbs  appear  we  begin  to  see  also  the  external  genital 
organs,  the  nose,  the  eyes,  the  ears,  and  the  mouth,  the  successive  de- 
velopment of  which  follows  the  course  mentioned  when  treating  of 
each  of  these  organs. 

The  insertion  of  the  umbilical  cord  gradually  ascends.  The  umbi- 
licus, however,  is  still  proportionally  much  nearer  the  symphysis  pubis 
in  the  full-grown  fetus  than  in  the  adult,  which  difference  is  directly 
connected  with  the  gradual  diminution  of  the  liver. 

III.  GROWTH. 

§ 2599.  The  fetus,  which  is  at  first  only  some  lines  long,  gradually 
becomes  in  ten  lunar  months  about  a foot  and  a half  in  length,  and 
about  six  pounds  in  weight. 

The  increase  is  very  rapid  at  first,  and  afterwards  is  gradually 
slower.  It  is  asserted  that  it  diminishes  at  the  second  month,  that  it 
becomes  more  active  in  the  third  month,  but  especially  during  the  se- 
cond half  of  the  fourth,  that  it  is  evidently  most  rapid  in  the  centre 
of  pregnancy,  and  that  it  consequently  becomes  slower  until  the  end 
of  pregnancy.(l)  This  proposition  is  proved  with  difficulty,  for  indi- 
vidual differences  may  easily  lead  into  error.  We  may  however  con- 
ceive it  to  a certain  extent,  by  attributing  this  slowness  to  the  disap- 
pearance of  the  umbilical  vesicle  about  this  period,  and  that  it  is  not 
completely  replaced  by  another  mode  of  nutrition. 

IV.  VITAL  PHENOMENA. 

§ 2600.  At  the  period  of  its  appearance  the  fetus  never  makes  part 
of  the  organism  of  the  mother.  Its  relations  with  the  mother  are  the 
same  as  those  between  the  child  and  the  external  world.  It  lives  a 
peculiar  life,  as  is  demonstrated  by  the  mode  of  connection  between 
the  two  organisms  mentioned  above. 

(1)  Autcnrieth,  Suppl,  ad.  hist,  embryon.,  p.  415. — Scemmcrring,  leones  embryo- 
nutti,  p.  Ü. 


523 


DESCRIPTIVE  ANATOMY. 


Among  the  vital  phenomena  those  connected  with  the  formation  are 
developed  in  the  greatest  degree,  and  at  the  expense  of  the  rest.  This 
is  proved  by  the  rapidity  with  which  the  fetus  increases  in  weight  and 
volume. 

But  the  different  functions  of  nutrition  take  place  precisely  in  the 
same  manner  in  all  essential  respects  before  and  after  birth.  We  have 
already  mentioned  the  activity  of  the  urinary  secretion.  The  intestinal 
canal  and  the  skin  are  also  active. 

§ 2601.  We  find  very  early  in  the  intestinal  canal  of  the  fetus  a 
fluid  which  has  not  the  same  qualities  at  all  periods.  Until  about  the 
centre  of  fetal  existence  this  liquid  is  whitish  and  mucous  : but  it  after- 
wards changes  to  a yellowish  green,  which  is  thicker  and  more  vis- 
cid. It  gradually  becomes  of  a darker  color  in  the  large  intestine, 
until  finally  in  the  latter  periods  of  pregnancy  it  has  the  same  qualities 
in  the  whole  intestinal  canal,  so  as  to  distend  it.  It  is  termed  the 
meconium.  It  is  formed  of  about  two  thirds  of  water,  about  one  third 
of  a peculiar  substance,  similar  to  vegetable  matter,  and  of  some  hun- 
dredths of  mucus.(l) 

Opinions  vary  in  regard  to  the  origin  of  the  mec'onium.  Some  con- 
sider it  a residuum  of  the  fluid  of  the  amnios  swallowed  by  the  fetus  ; 
others  think  it  formed  from  the  secretion  of  the  intestines. 

Although  the  fetus  very  probably  swallows  and  digests  the  fluid  of 
the  amnios,  yet  as  meconium  has  been  found  also  in  the  intestines  of 
fetuses  destitute  of  a head  and  mouth, (2)  in  a portion  of  the  canal 
situated  below  a septum  which  interrupted  the  continuity  of  the 
tube, (3)  in  a separate  end  of  the  intestine  which  was  closed  in  every 
part,  in  the  rudiment  of  a fetus  adhering  to  another  regularly  formed 
fetus, (4)  and  finally  in  the  intestines  of  another  perfect  body, (5)  it  is 
clear  that  the  deglutition  of  the  waters  of  the  amnios  are  not  necessary 
to  produce  it.  If  consequently  we  sometimes  find  it  only  above  the 
obstacle,  when  the  intestinal  canal  is  obliterated  in  any  part, (6)  we 
must  not  conclude  from  this  that  the  fluid  of  the  amnios  has  been 
swallowed,  and  that  the  meconium  is  formed  from  it, (7)  but  it  follows 
at  most  that  the  secretion  takes  place  principally  at  the  upper  part  of 
the  alimentary  canal.  We  thus  explain  the  peculiar  color  of  the  me- 
conium, which  might  be  attributed  to  the  bile,  since  the  tint  of  this 
fluid  changes  at  the  same  time  with  it, (8)  as  we  have  ascertained,  and 

(1)  Bouillon-Lagrange,  in  the  Annales  de  chimie , vol.  lxxxvi.  and  Ixxxvii. 

(2)  R.  de  Graaf,  De  mulier.  org.  ; in  the  Opp.  omn.,  p.  292.— Odhelius,  in  the 
fSchwcd.  Abhandlungen , 1785,  p.  176. — Gilibert,  Advers.  med.  pract.,  p.  132. 

(3)  Pied,  in  the  Journ.  de  med.,  an.  x.,  frimaire. 

(4)  Simmons,  Aledical  facts , vol.  viii.,  London,  1800,  p.  7. 

(5)  Brugmans,  in  Bernard,  Q uœst.  var.med.  argum.,  Leyden,  1796.  De  meconi. 
origine,  p.  31. 

(6)  Horch,  Eph.  nat.  cur.,  dec.  iii.  a iii.  p.  188.— Uesgranges,  in  the  Journ.  de 
méd.,  an.  x.,  thermidor. — Osiander,  Neue  Denkwürdigkeiten,  vol.  i.  p.  179. 

(7)  Osiander,  Handbuch  der  Entbindungskunde,  vol.  i,  p.  237. 

(8)  Lobstein,  p.  132.  , 


EMBRYOLOGY, 


523 


as  in  an  acephalous  full-grown  fetus  the  intestine  contained  a viscous, 
semitransparent  mucus,  not  colored  black. (1) 

It,  however,  remains  to  be  ascertained  whether  this  hypothesis  has 
any  foundation,  since  the  authors  who  describe  the  cases  mentioned  by 
us  formally  indicate  the  existence  of  a yellow  matter  having  the  qua- 
lities of  meconium,  and  chemical  analysis  has  not  proved  in  it  the 
existence  of  bile. (2) 

However  this  may  be,  the  bile  seems  to  have  some  part  in  pro- 
ducing the  meconium.  In  fact  in  some  cases,  particularly  in  that 
mentioned  by  Sims,  and  the  subject  of  which  was  a child  two  years 
old,  obliteration  might  be  caused  consecutively  ; in  others,  as  in  that 
described  by  Brugmans,  some  difference  is  stated  between  the  meco- 
nium in  that  portion  of  the  intestine  which  communicated  with  the 
biliary  system  and  that  inclosed  in  the  lower  intestine.  Thus  although 
the  bile  is  not  found  in  this  fluid,  it  may  perhaps  contribute  to  produce 
it.  Possibly  also  when  the  liver  is  deficient  the  intestinal  canal  sup- 
plies the  action  of  this  gland. 

§ 2602.  The  surface  of  the  body  of  the  fetus  is  covered  with  a sub- 
stance of  a peculiar  character,  termed  the  vernix  caseosa. (3) 

This  substance  is  yellowish  white,  viscous,  and  fatty. 

From  its  chemical  composition  it  is  between  the  fibrin  and  the  fat, 
and  very  much  resembles  adipocere.(4) 

It  does  not  exist  during  the  whole  of  gestation,  but  begins  to  appear 
about  the  sixth  month. 

Opinions  are  divided  in  respect  to  its  origin.  Some  consider  it  as  a 
precipitate  from  the  waters  of  the  amnios  deposited  on  the  surface  of 
the  body  of  the  fetus  :(5)  others  think  it  is  secreted  by  this  latter.(6) 

This  last  opinion  is  very  probably  more  correct  than  the  other.  In 
fact  : 

1st.  The  glandular  system,  particularly  that  of  the  sebaceous 
glands  of  the  skin,  is  much  more  developed  in  the  fetus  than  subse- 
quently. 

2d.  The  vernix  caseosa  is  very  abundant  in  the  parts  where  these 
glands  are  very  numerous,  in  the  head,  the  axillae,  and  the  inguinal 
regions. 

(1)  Monro,  Trans,  of  a soc.  of  Edinburgh , vol.  i.  p.  216. 

(2)  Simmons,  loc.  cit.,  p.  7. 

(3)  J.  J.  G.  Schulz,  De  ortu  et  usu  caseosæ  vernicis,  'Helmstadt,  1788. 

(4)  Buniva  and  Vauquelin,  Annales  de  chimie , vol.  xxxiii. — Emmert  and  Reusa 
Chemischi  Untersuchung  des  Fruchtwassers  aus  dem  zeitigen  Ei  und  der  käsigen 
Materie  auf  der  Haut  des  neugebornen  Kindes  ; in  Osiander,  Annalen  vol  ii 

p.  122. 

(5)  Boehmer,  De  aquis  ex  utero  gravid,  et  partur.  prof.,  Halle,  1769,  § ii. 

Schulz,  loc.  cit. 

(6)  Levret,  Art  des  accouchemens , 1766,  p.  75. — Schulze,  Anweisung  zur  Hebam- 
menkunt , Hildburgshausen,  1770,  p.  49.— Wrisberg,  in  Rcederer,  Eiern,  artis obstet., 
note  37.— Bmmert,  loc.  cit.,  p.  134.— Lobstein,  loc.  cit.,  p.  99.— Hunter,  Anat.  des 
swang.  Uterus,  p.  96. 


524 


DESCRIPTIVE  ANATOMY. 


3d.  It  is  found  only  in  the  fetus  : the  membranes  of  the  ovum  and 
the  umbilical  cord  present  no  trace  of  it. 

4th.  It  is  very  similar  to  the  substance  furnished  by  the  sebaceous 
glands  of  the  glans  penis,  and  its  qualities  do  not  allow  it  to  be  re- 
garded as  a precipitate  from  the  waters  of  the  amnios. 

§ 2603.  We  shall  demonstrate  hereafter  that  the  fetus  respires  by 
means  of  the  placenta. 

We  shall  also  mention  the  differences  presented  in  it  by  the  fetal 
circulation. 

§ 2604-  The  motions  of  the  voluntary  muscles  are  but  slight.  They 
generally  begin  to  be  felt  about  the  middle  of  pregnancy,  although  we 
cannot  conclude  from  this  that  they  do  not  occur  before,  since  they 
may  be  unperceived  on  account  of  the  smallness  of  the  fetus,  and  the 
abundance  of  the  waters  of  the  amnios. 

§ 2605.  The  fetus  necessarily  derives  in  the  body  of  the  mother 
the  materials  for  its  growth,  preservation,  and  its  secretions.  But 
here  a question  presents  itself:  Are  there  or  not  several  modes  of  nu- 
trition ? 

Different  authors,  particularly  Hippocrates,  Aristotle,  Galen,  Mon- 
ro,(1)  and  Danz,(2)  admit  only  one  mode  of  nutrition,  and  consider  the 
umbilical  vein  as  the  only  channel  through  which  nutrition  comes  to 
the  fetus. 

Others  believe  in  the  existence  of  several  other  channels,  as  the  skin 
and  the  system  of  the  mucous  membranes,  in  a greater  or  less  extent. 
According  to  this  last  hypothesis,  the  waters  of  the  amnios  are  the 
source  of  nutrition  for  the  fetus. 

Several  ancient  writers,  cited  by  Haller, (3)  and  among  the  moderns, 
Vas, (4)  Brugmans,(5)  Van  der  Bosch, (6)  and  Osiander,(7)  admit  that 
the  skin  absorbs. 

Opinions  vary  much  in  regard  to  the  extent  of  the  poition  of  the 
system  of  the  skin  which  contributes  to  nutrition. 

According  to  Harvey, (8)  Lacourvee,(9)  Haller, (10)  Treu, (11)  and 
Darwin, (12)  absorption  takes  place  only  by  the  intestinal  canal. 

Scheel(13)  asserts  that  it  occurs  also  by  the  lungs,  into  which  the 
waters  of  the  amnios  come  through  the  mouth  and  nose. 

(1)  Monro,  Essay  on  the  nutrition  of  the  fetus  ; in  the  Ed.  mcd.  essays,  vol.  ii. 
p.  102. 

(2)  Zerglicderungskundc  des  neugebornen  Kindes. 

(31  El.  phys .,  vol.  viii.  p.  205. 

(4)  C.  J.  Vos,  IJe  nutritione  imprimis  nervosa,  Utrecht,  17S9. 

(5)  In  Van  den  Bosch,  De  natura  el  ulilitate  liquoris  amnii,  Utrecht,  1792. 

(6)  Ibid. 

(7)  Handbuch  der  Entbindungskunde,  vol.  i.  p.  237. 

(8)  De  gcneralione , Amsterdam,  1662,  p.  253,  368. 

(9)  De  nutritione, fœtus  in  utero  paradoxa,  Dantzic,  1655. 

(10)  El.  phys.,  vol.  viii.  pt.  i.  p.  201. 

(11)  De  chylosi  fœtus,  Altdorf,  1715. 

(12)  Zoonomic,  vol.  i. 

(13)  De  liquoris  amnii  ulilitalc,  Copenhagen,  1795. 


EMBRYOLOGY. 


525 


To  these  parts  Lobstein(l)  adds  the  genital  organs  also. 

Finally,  Oken(2)  thinks  that  the  mammae  also  absorb  ; but  instead 
of  admitting,  as  had  already  been  done, (3)  that  the  fetus  absorbs  the 
milk  secreted  by  its  proper  mammae,  he  asserts  that  these  latter  organs 
absorb  only  the  waters  of  the  amnios,  and  that  the  fluid  introduced  by 
them  is  carried  by  their  lymphatic  glands  into  the  thymus  gland, 
whence  it  enters  the  thoracic  canal. 

The  following  have  been  considered  also  as  sources  of  the  nutrition 
of  the  fetus  : 

1st.  The  fluid  of  the  umbilical  vesicle. (4) 

2d.  That  of  the  allantoid  membrane. (5) 

. 3d.  The  gelatine  of  Wharton.(6) 

Those  who  maintain  several  modes  of  nutrition  think  that  they  are 
brought  into  use  simultaneously  or  successively.  The  first  opinion 
has  more  supporters  than  the  second. 

We  can  hardly  arrive  at  positive  results  until  we  have  mentioned 
and  discussed  the  arguments  of  each  party. 

§ 2606.  Those  physiologists  who  think  that  the  materials  of  nutri- 
tion are  brought  to  the  fetus  through  the  umbilical  vein,  rest  their  opi- 
nion upon  the  following  facts  : 

1st.  The  constant  and  general  existence  of  the  umbilical  cord,  the 
chorion,  and  the  placenta. 

2d.  The  ' peculiar  structure  of  these  organs,  and  their  connections 
with  the  fetus. 

3d.  Their  early  appearance. 

4th.  The  villosities  of  the  chorion  are  at  first  only  venous,  so  that 
they  have  no  function  but  that  of  absorption. (7) 

5th.  The  fatal  consequences  which  the  interuption  in  the  circula- 
tion of  the  blood  causes  in  the  nutrition  and  vitality  of  the  fetus. 

The  arguments  cited  by  the  partisans  of  nutrition  by  the  waters  of 
the  amnios  generally,  are  : 

1st.  The  existence  of  nutritious  materials  in  this  fluid. 

2d.  The  gradual  disappearance  of  these  materials,  and  the  diminu- 
tion of  the  liquid  near  the  end  of  pregnancy. 

3d.  The  fetus  continues  to  live  and  be  nourished,  although  the  cord 
is  altered  in  texture,  obliterated,  and  even  entirely  separated  from  the 
body,  the  umbilicus  being  perfectly  closed  at  birth. 

(1)  Essai  sur  Innutrition  du  fœtus,  p.  102. 

(2)  Zeugung , Hamburg’,  1805,  p.  162. 

(3)  Danz,  toc.  cit.,  vol.  ii.  p.  71. 

(4)  Needham,  De  formato  fœtu,  Loudon,  1C67,  p.  79. — Blumenbaeh,  Specim., 
physiolog.  comp,  inter  animalia  cal.  sang.  ovip.  et  vivip.,  Gottingen,  1786.— Id., 
Instit.  physiol.,  p.  449. — Soemmerring,  in  Haller,  Grundriss  der  Physiologic , 1796, 
vol.  ii.  p.  800. — Lobstein,  loc.  cit. — Emmert,  Vcbcr  das  Nabclblaschen  ; in  Riel,  _4r- 
chiv.  für  die  Physiologic,  vol.  x.  p.  77.— Jocrg,  Zeugung,  p.  286. 

(5)  Harvey,  Lobstein,  Oken. 

(6)  Lobstein. 

(7)  Lobstein,  loc.  cit.,  p.  117. 

VOL.  III. 


67 


526 


DESCRIPTIVE  ANATOMY. 


4th.  It  is  a fact  that  no  substance  can  be  placed  next  to  the  body, 
but  a mutual  action  and  reaction  is  established. 

5th.  The  parts  with  which  the  fluid  of  the  amnios  is  in  relation 
possess  the  power  of  absorption. 

We  consider  the  following  as  facts  which  demonstrate  absorption 
particularly  by  the  skin  : 

1st.  The  experiments  where  the  lymphatics  of  the  skin  are  filled 
with  the  fluid  of  the  amnios. 

2d.  The  known  instances  of  fetuses  without  a mouth  and  an  umbi- 
lical cord. 

Those  who  think  that  the  mucous  surfaces  absorb,  rest  their  opinion 
on  the  following  arguments  : 

1st.  The  necessity  that  the  waters  of  the  amnios  should  penetrate 
internally  in  cases  of  fissure  of  the  mouth  and  palate,  although  the 
fetus  does  not  become  thinner. 

2d.  The  existence  of  this  liquid  in  the  upper  part  of  the  intestinal 
canal,  the  lungs,  and  even  the  vagina. 

3d.  The  products  of  digestion  found  in  the  intestinal  canal. 

4th.  The  downy  hairs  of  the  fetus  found  in  the  meconium. 

5th.  The  motions  of  deglutition  observed  in  fetuses  immersed  in  the 
fluid  of  the  amnios.  Their  attempts  at  biting  and  sucking  before  and 
after  birth. 

6th.  The  existence  of  the  meconium  at  the  upper  part  of  the  intes- 
tine, when  the  canal  is  interrupted  in  any  portion  of  its  extent. 

Those  physiologists  who  think  that  the  liquid  in  the  umbilical  vesi- 
cle contributes  to  nutrition,  cite  : 

1st.  The  analogy  of  this  organ  with  the  vitelline  sac  of  the  other 
vertebrated  animals,  and  the  evident  passage  of  the  liquid  into  the 
intestinal  canal. 

2d.  The  great  size  of  the  umbilical  vesicle,  then  its  wasting,  at- 
tended with  a change  in  the  nature  of  the  fluid  within  it. 

We  have  already  mentioned  the  arguments  for  thinking  that  the 
liquid  of  the  allantoid  membrane  contributes  to  nutrition. 

Those  who  think  that  the  gelatine  of  Wharton  also  assists  in  this 
function,  adduce  : 

1st.  Its  nutritious  properties. 

2d.  Its  abundance  in  the  early  periods  of  fetal  existence,  which  is 
connected  with  the  shortness  and  size  of  the  umbilical  cord,  since  the 
size  of  this  cord  does  not  depend  solely  on  the  presence  of  a greater 
number  of  parts  within  it. 

3d.  The  observations  of  Noortwyk,  Rcederer,  and  Uttini,  which 
have  shown  that  fluids  can  be  made  to  pass  into  the  gelatine  of 
Wharton. 

4th.  The  greater  proportional  development  of  the  vessels  and  glands 
of  the  lymphatic  system  in  the  upper  half  of  the  anterior  face  of  the 


F.MERYOLOG  Y. 


527 


bodjr  on  leaving  the  umbilicus,  but  principally  in  the  anterior  medias- 
tinum,^) which  fact  we  have  always  proved. 

§ 2607.  Those  who  admit  but  one  mode  of  nutrition,  particularly 
that  by  the  umbilical  vein,  adduce,  first  the  fact  that  other  channels, 
particularly  the  absorption  of  the  waters  of  the  amnios  by  the  skin  and 
the  mucous  membranes,  are  insufficient  ; and  secondly  that  it  is 
indispensably  necessary  to  the  life  of  the  fetus  for  this  passage  should 
be  open. 

1st.  The  following  reasons  are  alledged  as  leading  one  to  think  that 
nutrition  by  the  waters  of  the  amnios  is  not  probable. (2) 

a.  The  liquid  is  formed  from  the  blood  of  the  fetus. 

b.  It  contains  but  little  nutritious  substance.(3) 

c.  A very  marked  alteration  in  its  composition  has  no  effect  on  the 
life  or  health  of  the  fetus. 

d.  The  fetus  continues  to  live  a greater  or  less  length  of  time  after 
the  dribbling  of  the  waters. (4) 

e.  The  instances  of  the  fetus  having  lived,  although  the  umbilical 
cord  was  interrupted,  obliterated,  or  separated  from  the  body,  are  not 
authentic. 

f.  There  is  a considerable  quantity  of  the  amniotic  fluid  at  the  end 
of  gestation. (5) 

2d.  Nutrition  by  the  skin  particularly  has  been  opposed  by  the  fol- 
lowing arguments  :(6), 

a.  The  caseous  envelop  which  covers  it. 

b.  The  necessary  stagnation  of  the  liquid  in  the  cellular  tissue  after 
penetrating  it. 

c.  The  viscidity  of  the  waters  of  the  amnios,  which  render  them 
unfit  to  enter  through  the  skin. 

3d.  The  arguments  against  the  entrance  of  this  liquid  through  the 
mouth  are  : 

a.  The  want  of  similitude  between  the  waters  of  the  amnios  and 
the  fluid  in  the  stomach. (7)  The  dissimilarity  even  between  these 
waters  and  the  meconium. (S) 

b.  The  impossibility  of  swallowing  unless  respiration  occurs.(9) 

c.  The  frequent  closing  of  the  mouth. (10) 

d.  The  fact  that  milk  injected  into  the  amnios  does  not  enter  the 
oral  passages.(ll) 

(1)  Lobstein,  p.  139. — Monro,  loc.  cit.,  p.  143. — Van  den  Bosch,  loc.  cit. 

(2)  Danz,  p.  59. 

(3)  Van  den  Bosch,  in  Schlegel,  p.  458. 

(4)  Van  den  Bosch,  p.  458. 

(5)  Monro,  p.  166. 

(6)  Haller,  El.  phys.,  viii.  p.  205. 

(7)  Monro,  p.  163. — Van  den  Bosch,  p.  460. 

(8)  Danz,  p.  60. 

(9)  Danz,  p.  59. 

(10)  Monro,  p.  173. — Van  den  Bosch,  p.  458  459. 

(11)  Monro,  p.  175. 


528 


DESCRIPTIVE  ANATOMY. 


c.  If  the  amniotic  fluids  penetrate  into  the  oral  cavity  by  any  pres- 
sure, they  would  be  introduced  into  the  trachea  as  well  as  into  the 
esophagus.(l) 

/.  Iustances  of  acephalous  and  astomatous  fetuses,  which  however 
were  fleshy.(2) 

g.  The  products  of  digestion  found  in  the  intestinal  canal  prove  no- 
thing, since  they  may  arise  solely  from  the  action  of  this  organ, (3)  and 
tho  more  as  meconium  also  has  been  found  above  the  point  where  ob- 
literation had  occurred. (4) 

h.  The  existence  of  the  meconium  and  the  hairs  in  the  stomach 
prove  nothing,  for  hairs  might  be  developed  in  the  alimentary  canal, 
and  the  meconium  pass  up  through  the  intestines  into  the  stomach. (5) 

i.  We  may  also  consider  deglutition  and  the  sucking  of  the  newly 
born  child  as  valueless,  since  numerous  other  phenomena  supervene  at 
the  period  of  birth,  although  the  system  has  made  no  previous  at- 
tempts, and  the  latter  had  already  commenced  before  parturition  by 
swallowing  the  waters  of  the  amnios. 

j.  The  existence  of  the  amniotic  fluid  in  the  stomach  is  abnormal, 
and  results  from  powerful  compression. (6) 

4th.  We  have  already  refuted  previously  the  arguments  which  go 
to  prove  that  the  fluid  of  the  allantoid  membrane  contributes  to  nu- 
trition. 

§ 2608.  We  have  now  to  examine  whether  all  the  arguments 
alledged  against  the  hypothesis  that  the  fetus  is.  nourished  by  the  fluid 
of  the  amnios  are  sufficient  to  refute  it. 

Strict  inquiry  determines  that  they  are  not. 

1st.  It  is  not  proved,  and  it  is  not  even  probable,  that  the  waters  of 
the  amnios  are  formed  from  the  blood  of  the  fetus,  since  the  vessels  of 
the  chorion  may  not  necessarily  be  other  than  the  organs  of  nutrition, 
and  the  fluid  of  the  amnios  may  be  secreted  by  the  uterus. 

2d.  The  slight  proportion  of  nutritious  materials  proves  nothing, 
because  nutrition  may  be  well  performed  with  substances  which  con- 
tain less  of  it,  and  also  because  the  fluid  of  the  amnios  at  first  contains 
more  of  it  ; finally  because  the  greater  energy  of  the  formative  power 
in  the  fetus  is  a sufficient  compensation. 

3d.  The  third  and  fourth  arguments  prove  at  most  only  that  the 
liquid  of  the  amnios  is  not  the  only  source  of  nutrition  in  the  fetus,  or 
that  the  fetus  might  exist  for  some  time  without  it  : even  this  latter 
circumstance  does  not  follow,  for  it  is  not  probable  that  the  fluid  of  the 
amnios  is  ever  reproduced  after  it  has  escaped. 

(1)  Danz,  p.  59. — G.  J.  C.  Themelius,  Comment,  qui  nulritionem  fœtus  in  utero 
per  vasa  umbilicalia  solum  fieri,  occasione  monstri  ovilli  sine  ore  et  faucibus  nati 
ostenditur,  Leipsic,  1751. — Van  den  Bosch,  p.  459. 

(2)  Danz,  p.  60. 

(3)  Van  den  Boscli,  p.  461. 

(4)  Brugmans,  in  Van  den  Bosch,  p.  461. 

(5)  Monro,  p.  177,  178. 

(6)  Danz,  p.  59,  60. 


EMBRYOLOGY. 


529 


4th.  We  cannot  apply  to  several  well  attested  cases  of  infants  being 
bom  with  the  umbilical  cord  really  obliterated,  the  too  general  objection 
that  all  those  of  this  kind  are  not  authentic  ; the  only  conclusion  how- 
ever to  be  drawn  from  this  is,  that  the  fetus  can  support  for  some  time 
the  interruption  of  its  communications  with  the  uterus  through  the 
medium  of  the  cord. 

5th.  The  existence  of  a great  quantity  of  the  liquid  of  the  amnios 
at  the  end  of  pregnancy,  is  without  value,  since  the  absolute  quantity 
of  the  liquid  is  generally  very  much  diminished  at  this  period.  If  it 
is  less  in  quantity  in  the  latter  periods  of  gestation,  the  only  conclusion 
to  be  drawn  from  this  is,  that  it  is  then  less  necessary,  which  coincides 
with  the  hypothesis  that  it  serves  for  nutrition,  as  the  formative  acts 
have  then  more  power,  and  also  possibly  another  more  efficacious 
mode  of  nutrition  is  then  developed. 

The  arguments  adduced  against  nutrition  through  the  skin  are 
easily  refuted. 

1st.  The  vernix  caseosa  does  not  exist  in  the  early  periods  of  gesta- 
tion, that  is,  v/hen  the  fluid  of  the  amnios  contains  most  nutrition,  and 
when  the  formative  acts  are  most  rapid.  Even  when  it  is  seen,  it  does 
not  form  on  the  skin  a uniform  layer  which  covers  it  so  as  to  prevent 
absorption. 

2d  and  3d.  There  is  no  proof  that  the  stagnation  of  the  amniotic 
fluid  under  the  skin  is  necessary,  and  of  the  impossibility  of  its  pene- 
trating farther.  This  stagnation,  on  the  contrary,  is  very  improbable. 

The  arguments  adduced  against  nutrition  by  the  mouth  are  not  con- 
clusive : for, 

1st.  The  dissimilarity  between  the  fluid  in  the  stomach  and  the  fluid 
of  the  amnios  is  easily  explained  by  a change  in  these  latter  ; farther, 
we  have  often  remarked  a perfect  identity  between  the  two  fluids. 

2d.  The  impossibility  of  swallowing  without  breathing  is  not  de- 
monstrated, and  certainly  is  not  a fact.  Farther,  the  fluid  of  the 
amnios  might  enter  into  all  the  cavities,  without  being  swallowed. 

3d.  The  closing  of  the  mouth  is  a useless  argument,  since  this 
does  not  always  occur,  and  the  mouth  has  been  observed  to  be  open 
in  the  fluid  of  the  amnios. 

4th.  The  same  is  true  in  regard  to  the  non-entrance  of  the  milk, -for 
in  these  experiments  the  animal  was  dead. 

5th.  The  penetration  of  the  fluid  of  the  amnios  with  the  trachea  is 
unattended  with  inconvenience  ; . perhaps  even  it  is  useful.  Farther 
observation  seems  to  demonstrate  that  it  really  occurs. 

6th.  The  acephalous  fetuses  only  prove  that  this  passage  is  not  the 
only  channel  through  which  nutrition  takes  place, 

7th.  The  development  of  the  hairs  is  so  rare  a phenomenon  that  the 
constant  existence  of  these  hairs  in  the  meconium  should  be  considered 
as  a very  peremptory  argument  in  favor  of  the  introduction  of  the  fluid 
of  the  amnios  into  the  alimentary  passages,  although  the  presence  of 
the  meconium  proves  nothing.  Besides  these  hairs  resemble  the  silky 
down  of  the  fejus. 


530 


DESCRIPTIVE  ANATOMY. 


8th.  Although  we  reject,  and  with  reason,  the  opinion  that  swal- 
lowing of  the  waters  of  the  amnios  would  be  a kind  of  prelude  to 
sucking  and  deglutition,  it  does  not  follow  that  when  this  liquid  is 
found  in  the  stomach  its  presence  should  be  regarded  as  unusual. 

§ 2609.  Thus  the  nutrition  of  the  fetus  .by  the  fluid  of  the  amnios 
still  continues  at  least  very  probable. 

It  is  no  less  difficult  to  doubt  the  nutrition  by  the  fluid  of  the  umbi- 
lical vesicle  and  the  gelatine  of  Wharton.  We  have  reason  to  think 
that  the  whitish  fluid  contained  in  the  placenta  constantly  passes  into 
the  body  of  the  fetus  through  the  umbilical  cord. 

But  it  is  very  improbable  that  the  fluid  of  the  allantoid  membrane 
contributes  to  its  nutritional ) 

§ 2610.  We  have  now  to  examine  if  nutrition  by  the  umbilical  vein 
rests  on  as  firm  a base  as  those  assert  who  think  it  the  only -source  of 
nutrition. 

We  cannot  at  least  deny  that  the  contrary  opinion  can  be  main- 
tained, since  the  facts  alledged  prove  only  the  necessity  of  the  circula- 
tion of  the  blood  in  the  chorion  and  placenta,  but  establish  nothing 
in  regard  to  the  function  of  these  parts. 

Farther,  as  the  fetus  is  nourished  in  three  other  modes,  and  as  it 
cannot  be  proved  that  these  three  modes  are  insufficient,  we  have  a 
right  to  admit  that  the  circulation  of  the  blood  in  the  placenta  by  the 
vessels  of  tire  fetus  has  not  the  uses  commonly  assigned  to  it,  provided 
always  that  we  mention  others  which  are  probable. 

But  this  is  possible.  In  fact  this  function  corresponds  to  respiration  ; 
several  physiologists,  both  ancient  and  modern,  have  compared  the 
placenta  to  the  lungs.(2) 

The  arguments  in  favor  of  this  opinion  are  : 

1st.  The  general  necessity  of  respiration,  which  cannot  be  performed 
in  any  other  manner. 

2d.  The  analogy  between  the  pulmonary  and  placental  circulations, 
the  placenta  and  lungs  both  receiving  the  blood,  from  which  the  se- 
tt) G.  F.  St.  Hilaire  (Monstruosités  humaines , p.  279)  having’  found  in  the  intes- 
tinal canal  an  anomocephalus  of  real  fecal  matters,  moulded  even  into  lumps  in  the 
post-ccecal  intestine,  was  led  by  this  phenomenon  to  examine  the  proper  nutrition  of 
the  fetus.  He  thinks  that  the  mucus  secreted  in  the  alimentary  passages,  and  which 
is  in  too  great  a quantity  to  be  used  simply  as  a lubricating  fluid,  is  the  aliment  first 
digested;  that  it  is  taken  up  at  first  by  the  digestive  organs,  then  by  thechyliferous  pas- 
sages, it  is  the  source  of  the  nutritious  fluid,  which  thus  flows  constantly  into  the 
circulatory  system,  and  which  at  each  passage  is  gradually  animalized.  Considered 
in  this  manner,  the  nutrition  of  the  fetus  would  resemble  that  of  the  adult.  This 
hypothesis,  in  accordance  with  which  the  discharge  of  mucus  would  be  caused  by 
the  irritation  of  the  mucous  membranes  by  the  bile,  is  very  ingenious,  but  is  impro- 
bable. In  fact  we  should  be  obliged  to  admit  that  the  alimentary  tube  acts  in  two 
totally  different  ways  in  regard  to  the  mucus,  one  action  forming  the  mucus,  the 
other  converting  it,  changing  it  into  chyle.  F.  T. 

(2)  Mayow,  Duverney,  Vallisneri,  Cheselden,  Hérissant,  Bœerhaave,  and  Jampert, 
in  Haller,  Elem.  physiol.,  vol.  viii.  p.  254. — Eckardt,  Q uestio  an  duæ  arteriœumbili- 
cales  feetui  pulmonum  loco  inserviunt,  Jena,  1761. — E.  Darwin,  Zoonomie,  vol.  i. — 
B.  N.  G.  Sclireger,  Defunctione  placentae  uterinæ,  Erlangen,  1795. — Lobstein,  loc. 
cit. — Oken,  Der  Atmungsprocess  des  Fötus  ; in  Lucina , vol.  iii.  p.  294. 


EMBRYOLOGY. 


531 


cretion  and  nutrition  of  the  body  are  derived,  and  which  must  conse- 
quently be  renewed. 

3d.  The  analogy  between  the  animals  which  breathe  by  bronchiæ, 
and  the  fetus  of  the  animals  which  have  lungs. 

4th.  The  rapidity  with  which  death  ensues,  when  the  circulation' 
through  the  placenta  is  interrupted. 

5th.  The  analogy  with  birds  and  reptiles,  in  which  the  blood  of  the 
umbilical  vessels  really  undergoes  through  the  egg-shell  the  changes 
produced  by  respiration. 

Very  probably  then  the  blood  of  the  fetus  is  really  changed  in  the 
placenta,  similarly  to  what  it  is  in  the  lungs,  and  the  arterial  blood  of 
the  mother  replaces  the  circulating  medium,  which  is  acted  upon  by 
the  oxygen. 

We  cannot  adduce  against  this  hypothesis  that  there  is  no  differ- 
ence in  the  color  of  the  blood  in  the  umbilical  vein  and  arteries,  as  se- 
veral observers  worthy  of  confidence  have  proved,  and  as  we  have 
satisfied  ourselves  on  several  occasions  ; for  possibly  the  fetus  having 
but  little  need  of  oxygen  its  blood  absorbs  but  a small  quantity,  and 
consequently  its  color  is  but  slightly  changed. 

Schweighæuser  has  advanced  an  opinion  directly  the  opposite  of 
this.(l)  He  thinks  that  the  function  of  the  placenta  is  to  change  that 
which  the  umbilical  veins  bring  to  it  into  venous  blood,  and  which 
does  not  suffer  this  change  in  the  body  of  the  fetus,  in  order  to  render 
it  proper  to  secrete  the  bile  and  to  form  the  solid  parts,  particularly  the 
nervous  system.  But  this  hypothesis  is  supported  by  no  fact,  but  it  is 
opposed  by  several.  Thus  nutrition  in  general,  and  that  of  the 
nervous  system  particularly,  is  performed  by  the  arterial  blood  ; the 
bile  may  be  formed  from  this  blood.  Besides  the  respiratory  function 
of  the  placenta  is  imperfect,  and  consequently  the  difference  between 
the  blood  in  the  umbilical  vein  and  arteries  is  almost  nothing.  We 
cannot  consider  that  of  the  vein  as  pure  arterial  blood,  since  it  has 
already  circulated  very  extensively  in  the  upper  half  of  the  body. 
Finally,  in  the  ovum  of  birds  the  blood  of  the  umbilical  artery  is  black, 
and  that  of  the  vein  is  red. 

The  placenta  then  is  principally  a respiratory  organ,  by  means  of 
the  circulation  in  the  umbilical  vessels. (2) 

(1)  &ur  quelques  points  de  physiologie  relatifs  à la  conception  et  à l'économie  or- 
ganique du  fœtus,  Strasburg-,  1812,  p.  19. 

(2)  G.  F.  St.  Hilaire  (Philosophie  anatomique,  p.  538)  thinks  that  the  fetus  respires 

through  allits  pores  like  the  aquatic  insects,  that  it  separates  the  air  from  thcsurround- 
ing  liquids,  and  that  the  uterus  performs  the  part  of  the  right  ventricle  by  sending 
the  amniotic  fluid  into  all  the  integuments  of  the  body.  This  opinion  has  been  con- 
firmed by  Lassaigne’s  discovery  of  a gas  very  analogous  to  the  atmospheric  air  in 
the  amniotic  fluid.  Muller  has  enlarged  upon  this  (De  respirations  fœtus  commen- 
tatio  physiologica,  Leipsic,  1823).  This  author  thinks  that  the  necessity  of  respira- 
tion of  the  fetus  is  to  that  of  the  child  as  10  : 15,  or  as  2 : 3.  But  the  placenta  also 
concurs  in  it  as  well  as  the  amniotic  fluids.  The  fine  experiments  of  Edwards  on 
the  asphyxia  of  the  batracia  are  naturally  connected  with  this  great  question,  and 
may  contribute  to  resolve  it.  F-  T. 


532 


DE8CRIPT1VE  ANATOMY. 


The  liver  probably  assists  in  this  function,  since  the  umbilical  vein 
ramifies  very  extensively  before  carrying  the  blood  into  the  ascending 
vena-eava. 

The  more  gross  nutritious  substance  is  introduced  through  the 
channels  mentioned  above. 

But  all  these  channels  do  not  exist  during  the  whole  of  fetal  exist- 
ence. 

The  umbilical  vesicle  first  becomes  inactive  in  the  second  month  of 
pregnancy.  After  the  first  half  of  gestation,  nutrition  by  the  waters  of 
the  amnios  diminishes  much,  because  the  fluid  lessens  in  quantity  and 
nutritious  qualities,  and  the  vernix  caseosa  diminishes  absorption  by 
the  skin.  It  would  seem  then  that  latterly  no  other  channel  exists 
but  the  gelatine  of  Wharton. 

V.  duration  of  the  fetal  state,  and  birth. 

§2611.  The  fetal  state  usually  continues  ten  lunar  months.  After 
this  period  the  fetus  is  born , that  is,  it  is  detached  from  the  body  of  the 
mother,  and  enters  into  a direct  relation  with  the  general  organism, 
being  now  capable  of  an  independent  existence. 

It  however  is  frequently  separated  before  the  normal  end  of  gesta- 
tion ; this  is  termed  abortion  (abortus).  The  union  between  the  two 
organisms  rarely  continues  too  long  ; this  is  termed  a late  birth  (partus 
tardivus , s.  serotinus). ( 1) 

The  fetus  cannot  survive  independent  of  the  mother  until  the  sixth 
month  of  gestation  : even  then  it  generally  dies. (2)  It  has  long  been 
disputed  to  what  extent  beyond  the  common  period  the  birth  may  be 
protracted  ; and  the  discussion  is  not  terminated.  The  possibility  of 
the  fact  cannot  be  doubted,  and  is  attested  by  several  authentic  in- 
stances. We  cannot,  however,  deny  that  a great  many  of  them  re- 
lated depend  on  the  necessity  in  order  to  render  them  legitimate,  of 
a conception  supervening  in  the  mother,  after  the  death  of  the  hus- 
band. 

§ 2612.  Parturition  is  accomplished  by  the  contraction  of  the  uterus, 
aided  by  that  of  the  abdominal  muscles.  These  contractions  com- 
mence at  the  base  of  the  organ,  while  the  slighter  fibres  of  the  neck 
gradually  cease  to  act.  Hence  the  cavity  of  the  uterus  shortens  and 
contracts,  and  consequently  all  parts  of  the  organ,  except  the  lower, 
greatly  compress  the  fetus,  which  escapes  through  the  part  which 
presents  the  least  resistance,,  that  is,  through  the  dilated  orifice  of  the 
uterus,  whence  it  passes  into  the  vagina,  and  then  through  the  ex- 
ternal orifice  of  the  genital  organs. 

(1)  Ucbcrfriili-und  spätreife  Geburlcn,  Mannheim,  1807. 

(2)  The  case  of  a fetus,  said  to  be  only  five  months  old,  which  lived  nine  months, 
has  recently  been  reported.  (V.  Kodman,  iu  the  Kd.  mod.  and  sui  t?.  Journal , vul.  xi, 
|\  455  ; vol.  xii.  p.  251.) 


EMBRYOLOGY. 


533 


Usually,  about  as  one  thousand  times  to  one,  the  membranes  of  the 
ovum,  which  enter  the  first,  break  before  the  fetus  has  left  the  cavity 
of  the  uterus,  and  most  of  the  fluid  of  the  amnios  escapes.  After  the 
fetus  is  expelled  the  uterus  is  freed  from  the  ovum,  by  the  contraction 
of  the  organ  following  parturition,  which  very  much  diminishes  the 
extent  of  the  surface  by  which  it  adheres,  and  ruptures  the  vessels 
which  unite  the  placenta.  When  the  posterior  fold  is  once  detached 
the  final  contractions  of  the  uterus  cause  its  expulsion. 

The  connections  between  the  ovum  and  the  ftterus  are  rarely  de- 
stroyed by  the  first  contractions  of  the  latter,  and  the  child  is  bom 
enveloped  in  its  membranes,  like  the  young  of  the  mammalia.  This 
case  probably  happens  only  in  continued  pregnancies.  It  is  normal, 
on  the  contrary,  in  abortion. 

§ 2613.  After  parturition,  lactation  also  establishes,  for  a greater  or 
less  length  of  time,  a material  connection  between  the  mother  and  the 
child. 

The  mammae  during  pregnancy  are  changed  like  the  uterus.  They 
enlarge,  become  more  vascular,  softer,  and  looser.  Their  granulations 
are  more  distinct.  In  a word,  they  resemble  the  other  glands,  the 
secretory  activity  of  which  continues  uninterruptedly,  while  preg- 
nancy assimilates  the  uterus  to  the  muscles  which  are  constantly  in 
action. 

The  secretion  of  the  milk  begins  in  the  last  weeks  of  pregnancy,  but 
it  is  very  imperfect. 

The  human  milk,  like  that  of  the  other  females  of  the  mam- 
malia, is  decomposed  by  rest  into  two  parts,  one  fat  and  yellowish,  the 
other  serous  ; the  former,  or  the  cream,  divides  into  butter  and  butter- 
milk. The  cream  and  the  creamy  milk  both  contain  a substance  ana- 
logous to  albumen,  the  caseous  substance,  of  which  there  is  but  little 
in  the  milk  of  the  female,  and  it  is  there  softer  and  less  coagulable  than 
in  that  of  other  animals.  It  is  coagulated  by  heat  and  acids,  and  thus 
it  may  be  obtained  separately.  The  serous  portion  of  the  milk,  when 
entirely  freed  from  caseous  substance,  has  a sweetish  taste,  which  is 
owing  to  the  sugar  of  milk,  which  abounds  in  the  milk  of  the  female. 
Many  calcareous  salts  exist  in  the  caseous  matter.  The  slight  quan- 
tity of  this  latter  and  its  softness  prevents  the  milk  of  the  female  from 
coagulating,  or  at  least  but  slightly.  It  is  asserted  that  its  cream 
does  not  give  butter,  which  is  not  true. 


Vol.  111. 


6S 


534 


DESCRITTIVE  ANATOMV. 


CHAPTER  II. 

OF  CONCEPTION  IN  THE  ABNORMAL  STATE. (1) 

§ 2614.  The  anomalies  in  the  genital  organs  connected  with  coition, 
pregnancy,  and  parturition,  are  less  numerous  and  less  worthy  of  no- 
tice than  those  presented  by  the  new  organism. 


I.  GENITAL  ORGANS. 

§ 2615.  An  anomaly  sometimes  occurring  in  the  organs  of  coition 
is  the  continuance  of  the  hymen  after  copulation,  and  sometimes  after 
parturition.  It  deserves  attention,  as  it  indicates  that  the  presence  of 
this  fold  is  not  a certain  sign  of  virginity,  and  as  it  renders  parturition 
difficult,  particularly  when  the  hymen  is  solid. 

Among  the  anomalies  of  the  genital  organs  of  the  female,  of  which 
we  have  already  spoken  above,  the  adhesion  of  the  abdominal  extre- 
mities of  the  Fallopian  tubes  with  the  adjacent  organs,  particularly 
with  the  anterior  and  posterior  face  of  the  broad  ligaments,  the  uterus, 
the  bladder,  the  rectum,  and  the  ovaries,  and  the  obliteration  of  their 
abdominal  orifices,  are  principally  results  of  coition.  These  two  states 
are  observed  particularly  in  prostitutes, (2)  where  they  are  probably 
produced  by  the  frequent  and  excessive  stimulation  of  the  genital 
parts.  They  are  also  common  in  sterile  females,  and  should  be  re- 
garded as  the  most  usual  cause  of  sterility,  since  they  prevent  the 
motion  of  the  tubes,  and  the  entrance  of  the  fluid  from  the  ovaries  into 
the  uterus. 


II.  NEW  ORGANISM. 


§ 2616.  We  shall  examine  here,  among  the  anomalies  which  may 
supervene  on  conception  and  in  the  formation  of  a new  organism,  only 
those  which  affect  the  whole  new  being  and  the  ovum  particularly, 
since  we  have  already  mentioned  the  deviations  in  the  formation  of 
the  fetus,  either  generally  or  particularly,  in  the  several  parts  of  this 
work. 

1st.  The  first  anomaly  of  the  ovum  is  the  place  where  it  is  formed. 
The  anomaly  is  greatest  in  this  case  when  the  ovum  is  situated  out  of 


(1)  Wrisberg,  De  secundinarum  humanarum  varietate,  Gottingen,  1773. — Schæfer, 
De  placentœ  uterinœ  morbis,  Leipsic,  1799. — Michaelis,  De  placenta  humana,  ana- 
tomice,  physiologice  et  palhologice  considerata,  Erford,  1782. — Hebenstreit,  De  funi- 
culi umbilicalis  pathologia,  Leipsic,  1747. 

(2)  Walter,  Ueber  die  Krankheiten  des  Bauchfelles , p.  13. — Langstaff,  in  the  Med. 
chir.  trans.,  vol.  viii.  p.  505. 


EMBRYOLOGY. 


535 


the  uterus.  This  is  termed  extra-uterine  conception  or  gestation  (con- 
ceptions. graviditas  extra-uterina) .(1)  The  ovum  is  then  developed 
ia  the  ovary,  in  the  abdominal  cavity,  or  in  the  Fallopian  tube. (2) 
The  uterus  generally  changes  as  it  does  in  pregnancy  ; this  organ  is 
enlarged,  softens,  and  a deciduous  membrane  forms  in  it.  In  the 
cases  where  it  is  asserted  that  the  latter  did  not  exist,  it  had  probably 
already  disappeared,  or  it  was  developed  imperfectly.(3)  The  ovum 
is  destitute  of  it. 

As  to  the  fetus  : 

a.  It  is  regularly  formed,  a very  rare  phenomenon,  observed  princi- 
pally in  abdominal  pregnancy. 

b.  It  is  dead  ; this  is  more  frequent,  and  causes  in  the  adjacent  parts, 
principally  the  rectum,  the  integuments,  or  the  vagina,  rarely  in  the 
bladder,  the  formation  of  an  abscess,  and  is  usually  discharged  through 
the  opening  in  pieces,  more  rarely  entire. 

c.  Long  before  the  first  months  of  pregnancy  have  elapsed,  and  even 
during  its  first  fifth,  the  too  slightly  extensible  part  in  which  the  fetus 
is  developed  is  ruptured,  and  the  mother  dies  from  an  internal  hemorr- 
hage, which  termination  is  observed  particularly  in  pregnancy  of  the 
Fallopian  tubes. 

d.  The  fetus  and  its  envelops  less  rarely  adhere,  and  ossify  more  or 
less  perfectly.  The  mass  often  continues  so  for  years,  and  the  female 
lives. 

More  commonly  the  situation  of  the  placenta  in  the  uterus  varies, 
being  developed,  particularly  in  twin  pregnancies,  at  the  lower  part  of 
the  ovum,  on  the  edge  of  the  orifice  of  the  uterus  (placentas  prcevia,  s. 
oblata). 

Finally,  a more  common  anomaly  is  the  twisting  of  the  umbilical 
cord. 

2d.  The  simultaneous  formation  of  several  ova  and  fetuses.  The 
following  are  the  most  general  remarks  on  this  subject  : 

a.  There  is  generally  a predisposition  to  this  anomaly,  since  the 
same  parents  and  the  same  mothers  produce  several  twins. 

b.  The  number  of  coexisting  fetuses  is  never  more  than  five.  We 
may  generally  admit  that  twin  pregnancies  are  to  common  preg- 
nancies as  1 . 100,  triplets  as  1 : 1000,  and  quadruplets  as  1 : 50,000- 
60,000. 

(1)  See  our  Handbuch  der  pathologischen  Anatomic,  vol  ii.  p.  160-180. — J.  H. 
Giessmann,  Diss.  dc  conceptione  duplici  uterina  vimirum  ct  ovaria  uno  eodemque 
temporis  momento  facta,  Marburg’,  1820. — F.  F,  Susewind,  De  graviditate  ovaria, 
Berlin,  1820. 

(2)  It  may  also  be  developed  in  the  proper  substance  of  the  uterus,  although  not 

separated  from  the  tissue  of  this  vise  ns  by  a cyst.  This  has  been  observed  by 
Schmitt,  Hedrich,  Carus,  and  Breschet.  Carus  (Zur  Lehre  von  Schwangerschaft 
und  Gebert,  Leipsic,  1822)  thinks,  but  wrongly,  that  in  these  cases  the  ovule  glides 
and  lodges  between  the  peritoneum  and  the  uterus.  F.  T. 

(3)  This  occurred  in  a case  reported  by'  Langstaff.  (Med.  c hir.  trans.,  vol.  vij.  p. 
441.) 


53G 


DESCRIPTIVE  ANATOMY. 


c.  Generally  in  a case  of  twins  or  triplets  the  placentas  are  united 
in  one,  but  there  are  two  or  three  choria,  two  or  three  amnia,  and  two 
or  three  umbilical  cords,  so  that  the  two  or  three  fetuses  are  entirely 
separate.  When  two  are  situated  in  the  same  cavity  the  intermediate 
septum  has  evidently  been  destroyed. 

The  umbilical  vessels  usually  communicate  on  the  inner  face  of  the 
placenta  by  a large  transverse  anastomosis,  which  arises  at  the  root  of 
the  cord.  This  anastomosis  is  rarely  deficient.  This  has  been  wrongly 
termed  a third  placenta.(l) 

We  do  not  as  yet  know  how  the  umbilical  vesicle  is  arranged  where 
there  are  numerous  fetuses. 

d.  In  regard  to  the  fetuses,  even  when  there  are  but  two,  one  and 
sometimes  both  are  small  and  imperfect,  often  to  a great  degree,  for 
most  monsters  which  are  very  abnormal  are  generally  twins.  (2)  This 
phenomenon  is  still  more  evident  when  there  are  more  than  two  fe- 
tuses, for  then  all  are  generally  smaller,  and  are  not  nourished  as  well 
as  usual.  Sometimes  also  the  existence  of  two  fetuses  causes  the 
death  of  one  of  them  at  a more  or  less  advanced  period. 

e.  In  a twin  pregnancy,  and  still  more  in  triplets,  parturition  usually 
occurs  before  the  regular  period  of  gestation.  Generally  all  the  fe- 
tuses, and  even  those  which  are  dead,  leave  the  uterus  at  the  same 
period.  Sometimes,  however,  one  of  the  two  is  expelled  prematurely, 
while  the  second  remains  until  the  regular  period,  and  is  then  born. (3) 
In  some  cases,  but  this  is  less  remarkable,  the  dead  infant  is  not  bom 
till  some  days  after  the  other,  which  is  perfectly  full  grown. (4) 

The  fetuses  which  coexist  in  the  uterus  have  generally  been  pro- 
duced by  the  same  generative  act.  They  are  formed  much  less  com- 
monly by  several  successive  actions  ; this  constitutes  superfeiation 
( superfelatio).(5 ) The  possibility  of  this  fact  is  proved,  first,  by  cases 
where  the  woman  has  borne  two  children  of  different  color,  and  as- 
serted that  she  had  cohabited  with  men  of  different  races  ; secondly, 
by  those,  although  they  are  less  authentic  in  fact,  which  mention  full 
grown  children  born  at  an  interval  of  several  weeks,  and  even  several 
months. 

§ 2617.  Superfetation  is  explained: 

1st.  By  the  existence  of  a more  or  less  divided  uterus. (6) 

2d.  By  a productive  coition,  followed  by  another  also  productive, 
before  the  ovum  produced  by  the  first  had  arrived  into  the  uterus. (7) 

(It  Stalpart  van  der  Wiel,  cent.  i.  p.  75.— Otto,  Path.  Anal.,  p.  38. 

(2)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  i.  p.  55. 

(3)  J.  Chapman,  Singular  case  of  expulsion  of  a blighted  fetus  and  placenta  at 
seren  months,  a living  child  still  remaining  the  full  period  of  utero-gestalion  ; in 
the  Med.  chir.  trans.,  vol.  ix.  p.  194. 

(4)  Clarke,  in  the  Med.  and  phys.  Journ.,  vol.  xvi.  p.  53. 

(5)  J.  P.  Gravel,  Re  svpcrfetatioue  conjectures,  Strasburg1,  1738. — M.  Tydeman, 
l)e  superfetatione,  Utrecht,  1 783. — T.  Roose,  De  super fetatione  nonnulla , Bremen, 
1801. — .1.  C.  Varrentrapp,  C'omm.  in  T.  Roose  dc  superfetatione,  Frankfort,  1803. 

(6)  Gravel,  Roose. 

(7)  Varrentrapp. 


EMBRYOLOGY. 


537 


3d.  By  the  laceration  of  a portion  of  the  deciduous  membrane, 
which  forms  a passage  for  the  semen  to  the  Fallopian  tube.(l) 

Thus  all  the  theories  given  are  purely  mechanical.  These  expla- 
nations are  by  no  means  worthless  ; superfetation,  however,  more  pro- 
bably, depends  principally  on  the  fact  that  one  coition  calls  into  action 
several  vesicles,  which  do  not  arrive  at  the  same  degree  of  vital  ac- 
tivity simultaneously,  even  as  in  birds  a single  copulation  is  sufficient  to 
impregnate  a considerable  number  of  yolks,  which  differ  much  in  res- 
pect to  their  development. 

Superfetation  may  also  depend,  in  certain  rare  cases,  on  no 
mechanical  cause,  but  on  the  fact  that  the  capacity  of  the  genital 
organs  and  the  whole  organism  of  the  female  is  not  unfitted  by  the 
first  conception  for  a second  during  the  course  of  the  other  ; even  as 
the  disposition  for  contagious  diseases,  to  which  generation  is  so  ana- 
logous, is  commonly  lost  by  the  first  infection,  although  a second  su- 
pervenes in  rare  cases  ; or  as  one  exanthematous  affection  is  gene- 
rally, but  not  always,  arrested  by  another. 

§ 2618.  The  new  organism  is  sometimes  destitute  of  certain  parts. 
The  most  common  anomaly  in  this  case  is  the  absence  of  the  fetus, 
which  undoubtedly  depends  generally  on  the  fact  that  this  latter  has 
perished  sooner  or  later,  since  the  ovum  is  commonly  formed  of  all  the 
parts  which  normally  compose  it,  and  we  there  perceive  even  more  or 
less  evident  proofs  of  the  previous  existence  of  a fetus. 

The  placenta  is  deficient  more  rarely.  In  one  case  of  the  kind  re- 
cently described(2)  it  was  asserted  that  the  umbilical  cord  was  at- 
tached to  the  inner  face  of  the  ovum  in  the  form  of  a button. 

The  defect  of  an  umbilical  vessel,  particularly  of  an  artery,  is  more 
common. 

We  more  rarely  find  the  umbilical  vein  double,  which  establishes  an 
analogy  with  most  mammalia. 

§ 2619.  The  deviations  in  the  formation  of  the  ovum  relate  princi- 
pally to  the  placenta  and  the  umbilical  cord. 

The  placenta  is  sometimes  but  proportionally  very  rarely  divided 
into  several  lobes  (; ■placenta  succenturiata ),  only  two  of  which  generally 
appear,  although  there  are  sometimes  seven.  One  of  these  lobes  is 
generally  larger  than  the  others.  This  anomaly  consists  in  a suspen- 
sion of  development.  We  have  observed  it  principally  in  pregnancy 
with  twins,  and  we  have  always  been  satisfied  that  authors  were 
mistaken  in  saying  that  the  umbilical  vessels  then  divided  unusually 
soon. 

This  premature  division  of  the  umbilical  vessels,  even  within  the 
membranes  of  the  ovum,  is  rare  : but  it  is  still  more  so  for  the  vessels 
to  separate  on  the  outside  of  the  body  of  the  child. 

(1)  Tydeman. 

(2)  Conby,  in  the  Salz.  med.  chir.  Zeitung,  1819,  no.  43. 


53S 


DESCRIPTIVE  ANATOMY. 


We  must  arrange  here  the  knots  of  the  umbilical  cords  termed  true, 
when  they  are  real,(l)  and  false , when  they  consist  only  in  more  or 
less  compact  circumvolutions  of  the  umbilical  vessels. 

§ 2620.  The  umbilical  cord  presents  anomalies  in  its  extent.  Some- 
times it  is  too  short,  being  only  four  inches  in  length.  Less  frequently 
it  is  unusually  long,  being  fifty  inches  in  length.  Sometimes  also  it  is 
very  thin  or  lean , which  depends  on  the  small  quantity  of  the  gelatine 
of  Wharton.  In  other  cases  it  is  unusually  fat. 

The  placenta  is  commonly  much  larger  and  much  thinner  than 
usual  in  abdominal  pregnancy. 

Here  are  referred  the  change  of  the  vessels  of  the  placenta  into 
larger  and  smaller  vesicles,  entirely  closed  and  united  by  contracted 
portions,  which  seem  to  depend  on  the  permanence  and  the  ultimate 
development  of  a state  primitively  normal. 

§ 2621.  Anomalies  in  the  connections  relate  to  those  of  the  ovum 
with  the  uterus  or  fetus.  Sometimes,  but  rarely,  the  first  are  firm. 

Sometimes  the  fetus  is  not  connected  with  the  ovum.  This  pheno- 
menon is  not  rare  in  the  early  periods  of  gestation,  and  we  may  also 
consider  it  as  the  result  as  well  as  the  cause  of  the  death  of  the  fetus. 
But  authors  relate  also  cases  in  which  this  insulation  was  observed  at 
an  advanced  age  of  pregnancy.  Here  we  refer  to  the  observations  of 
Chatton,(3)  Stalpart  van  der  Wiel, (4)  Rommel, (5)  Mason  Good, (6) 
and  Osiander.(7) 

All  these  facts  are  not  equally  authentic.  Thus  Stalpart  van  der 
Wiel  did  not  observe  the  case  mentioned  by  him  until  several  months 
after  birth  ; there  was  at  the  time  an  inversion  of  the  bladder  ; the 
umbilicus  was  situated  too  low,  and  blended  with  the  upper  part  of  the 
bladder,  and  seemed  to  be  deficient. 

On  the  other  hand  the  fetus  is  sometimes  connected  with  the  mem- 
branes of  the  ovum  too  intimately. 

Here  are  referred  the  cases  where  the  umbilical  cord  is  inserted  in 
an  unusual  part  of  the  body,  and  is  there  attached  in  a greater  or  less 
extent  before  arriving  at  the  abdominal  cavity. (8) 

Such  are  also  those(9)  in  which,  besides  the  umbilical  cord,  a liga- 
ment arose  from  the  membranes  of  the  ovum,  and  was  attached  to  the 
body  of  the  fetus. (10) 

(1)  Delius,  De  noclis  veris  in  f uniculo  umbilicali,  Gottingen,  1605. 

(2)  Gregurini,  De  hydrope  uteri , Halle,  1795. 

(3)  Ephem.  Gallic,  ann .,  673,  fol.  69,  cited  by  Stalpart  van  der  Wiel,  Obs.  rar. 
cent.  ii.  pt.  ii.  p.  329. 

(4)  Observât,  rar.  med.  chir.,  cent.  ii.  pt.  i.  obs.  32. 

(5)  Eph.  nat.  cur.,  dec.  ii.  ann.  vii.  obs.  209. 

(6)  Stark,  Neues  Archiv.,  vol.  i.  p.  357. 

(7)  Annalen,  vol.  i.  pt.  i.  p.  199. 

(8)  Meckel,  Handbuch  der  pathologischen  Anatomie,  vol.  ii.  pt.  i.  p.  56. 

(9)  lbid. 

(10)  G.  F.  St.  Hilaire  attributes  the  frequent  monstrosities  of  the  fetus  which  so 

frequently  deform  it,  to  these  folds.  F.  T. 


EMBRYOLOGY. 


539 


§ 2622.  The  principal  alterations  of  texture  are,  the  too  great  hairi- 
ness of  the  membranes  of  the  ovum,  generally  attended  with  their 
thickening  : the  development  of  the  new  formations  in  the  placenta,(l) 
or  of  serous  cysts  in  the  cord  ; finally,  the  changes  of  the  whole  ovum, 
termed  moles,  and  which  are  divided  into  several  classes,  according  to 
the  different  substances  which  form  them. 

§ 2623.  Parturition  presents  numerous  anomalies,  the  causes  of 
which  exist  in  the  body  of  the  mother,  or  in  that  of  the  child,  or  in 
both.  These  anomalies  become  also  the  source  of  several  of  those 
mentioned  when  speaking  of  the  genital  organs,  particularly  of  dif- 
ferent deviations  of  formations,  as  lacerations  of  the  uterus,  the  vagina, 
adhesion  and  obliteration  of  the  orifice  of  the  uterus,  the  vagina,  and 
the  vulva,  after  an  injury. 


(I)  Clarke,  in  the  Phil,  trans.,  1798,  p.  11. 


, 


. 


INDEX  TO  VOLUME  III 


PAGE 

Sect.  II.  Periphery  of  the  nervous  system,  . . . „ 4 

Chap.  I.  Nerves  of  the  spinal  marrow,  .....  5 

Art.  i.  Dorsal  nerves,  .......  8 

Art.  11.  Lumbar  and  sacral  nerves,  . . . . .11 

A.  Anterior  branches,  . . . . . . .13 

B.  Nerves  of  the  lower  extremities,  ...  . . 15 

I.  Obturator  nerve,  . . . . . . . 15 

II.  Crural  nerve,  .......  16 

III.  Sciatic  nerve,  . . . . . . .17 

а.  Peroneal  nerve,  .....  . . 18 

б.  Tibial  nerve,  .......  19 

Art.  iii.  Cervical  nerves,  .......  21 

A.  Nerves  of  the  upper  extremities,  .....  22 

I.  Thoracic  nerves,  .......  24 

II.  Scapular  nerve,  .......  24 

III.  Axillary  nerve,  .......  24 

IV.  Radial  nerve,  .......  25 

V.  External  cutaneous  nerve,  ......  26 

VI.  Median  nerve,  .......  26 

VII.  Ulnar  nerve,  .......  27 

VIII.  Internal  cutaneous  nerve,  . . . . . 29 

B.  Superior  cervical  nerves,  ......  29 

I.  Diaphragmatic  nerve,  ......  30 

II.  Fourth  cervical  nerve,  ......  31 

III.  Third  cervical  nerve,  ......  32 

IV.  Second  cervical  nerve,  .......  33 

V.  First  cervical  nerve,  . . . . . . 34 

Chap.  II.  Encephalic  nerves,  ......  36 

I.  Hypoglossal  nerve,  .......  39 

II.  Accessory  nerve,  ....;..  42 

III.  Pneumogastric  nerve,  . . . . . .44 

IV.  Glosso-pnaryngeal  nerve,  . . ■ . . . .60 

V.  Auditory  nerve,  .......  52 

VI.  Facial  nerve,  ........  53 

i.  Ascending  branches,  . . ...  . . .55 

a.  Temporal  nerves,  .......  55 

b.  Malar  nerves,  .......  56 

11.  Anterior  branches  or  buccal  nerves,  . • . 66 

in.  Descending  branches,  . . . • • . 56 

VII.  External  motor  nerve,  ......  67 

VIII.  Trifacial  nerve,  .......  59 

A.  First  branch,  ........  62 

B.  Second  branch,  .......  65 

C.  Third  branch,  ........  71 

IX.  Internal  motor  nerve,  .......  75 

X.  Common  motor  nerve,  .......  76 

XI.  Optic  nerve,  ........  77 

Chap.  III.  Ganglionnary  nerve,  ......  83 

I.  Central  portion,  ........  85 

II.  Limiting  cord  and  its  branches,  .....  08 

A.  Superior  cervical  ganglion,  .....  gg 

I.  Upper  branches,  • - • • • 80 

V Oh.  Ill 


69 


542 


INDEX. 


PAGE 

II.  External  branches,  92 

III.  Internal  branches,  . . _ _ ! 92 

IV.  Anterior  branches,  - . . . * . 92 

V.  Inferior  branches,  ......  93 

B.  Middle  cervical  ganglion,  . . . . 94 

C.  Inferior  cervical  ganglion,  ......  95 

I.  Cardiac  plexus,  96 

D.  Thoracic  ganglions,  96 

i.  Splanchnic  nerve,  .......  97 

11.  Small  sphlanchnic  nerve,  . . . j 97 

E.  Abdominal  ganglions,  • 97 

Chap.  IV.  Differences  in  the  nerves  during  development,  ...  99 

Chap.  V.  Parallel  between  different  nerves,  . . . ’ 101 

BOOK  III.  Splanchnology,  . . . . . . .109 

Sect.  I.  Organs  of  sense,  . . . . . . .110 

Chap.  I.  Organ  of  hearing,  . . . - . . . .Ill 

Art.  i.  External  ear,  .......  112 

A.  Cartilage  of  the  ear,  . . . . . . 442 

B.  Muscles  of  the  external  qar,  ......  114 

I.  Muscles  moving  the  external  ear,  . . . . .114 

A.  Attollens  auricula,  . . ...  . 115 

B.  Retrahentes  auricula:,  . . . . . .115 

C.  Attrahens  auriculae,  ......  115 

II.  Muscles  moving  certain  parts,  . . . . .115 

a.  Tragicus,  . . . . . . .116 

b.  Antitragicus,  . . . . . . .116 

c.  Hclicis  major,  . . . . . . . 116 

d.  Helicis  minor,1  .......  116 

e.  Transversus  auriculæ,  . . . . . .116 

Art.  ii.  Internal  ear,  .......  117 

A.  Externalportion,  .......  117 

I.  Osseous  portion,  .......  117 

II.  Membrane  of  the  tympanum,  . . . . .118 

B.  Middle  part,  ...  .....  119 

I.  Tympanum,  . . . . . . .119 

II.  Eustachian  tube,  .......  121 

III.  Bones  of  the  ear,  121 

a.  Malleus,  ........  122 

b.  Incus,  .........  122 

c.  Lenticular  bone,  .......  123 

d.  Stapes,  ........  123 

IV.  Muscles  of  the  bones  of  the  ear,  .....  123 

a.  Muscles  of  the  malleus,  ......  124 

1.  Tensor  tympani  muscle,  .....  124 

2.  Laxator  tympani  major  muscle,  ....  124 

3.  Laxator  tympani  mirtor  muscle,  ....  124 

b.  Stapedius  muscle,  ......  125 

C.  Labyrinth,  ........  125 

I.  Osseous  labyrinth,  .......  125 

a.  Vestibule,  .......  126 

b.  Semicircular  canals,  . . . . . .126 

c.  Cochlea,  ........  127 

d.  Aqueducts,  .......  129 

II.  Membranous  labyrinth,  ......  131 

III.  Auditory  nerve,  .......  132 

Art.  hi.  Differences  dependent  on  development,  ....  134 

Art.  iv.  Abnormal  state  of  the  organ  of  hearing,  . . . 140 

Chap.  II.  Organ  of  sight,  .......  143 

Art.  i.  Parts  which  protect  the  eye,  .....  143 

I.  Eyelids,  .........  144 

A.  Eyelashes,  ........  144 

B.  Meibomian  glands,  .......  144 

C.  Palpebral  cartilages,  . . . . . . . 144 

D.  Muscles  of  the  eyelids,  ......  146 


INDEX. 


543 


P 

A.  Orbicularis  palpebrarum,  . . . ... 

B.  Levator  palpebræ  superioris,  . . . - . 

E.  Caruncula  lachrymalis,  ...... 

II.  Eyebrows,  . .•>  .... 

ill.  Lachrymal  passages,  ...... 

A.  Lachrymal  gland,  . ...... 

K.  Lachrymal  puncta  and  lachrymal  passages, 

C.  Lachrymal  sac,  ....... 

Art.  ii.  Globe  of  the  eye,  ....... 

I.  Membranes  of  the  eye,  ...... 

A.  External  membranes,  ...... 

A.  Sclerotica,  ....... 

B.  Transparent  cornea,  ...... 

B.  Choroid  membrane  and  iris,  ..... 

A.  Choroid  membrane,  ...... 

B.  Ciliary  body,  . . . . 

C.  Iris,  

D.  Pigment,  ....... 

C.  Retina,  ........ 

II.  Humors  of  the  eye,  ....... 

A.  Vitreous  humor,  ....... 

i.  Crystaline  lens,  ....... 

B.  Aqueous  humor,  ......  * 

Art.  hi.  Muscles  of  the  eye,  ...... 

I.  Straight  muscles,  ....... 

i.  Rectus  superior,  ....... 

ii.  Common  tendon  of  the  other  three,  .... 

nr.  Rectus  externus,  ....... 

iv.  Rectus  inferior,  ....... 

v.  Rectus  internus,  ....... 

II.  Oblique  muscles,  ....... 

i.  Obhquus  superior,  ....... 

ii.  Obliquus  inferior,  . . . . . 

Art.  iv.  Functions  of  the  eye,  ...... 

Art.  v.  Differences  in  the  eye  dependent  on  development, 

Art.  vi.  Abnormal  state,  ....... 

Chap.  III.  Organ  of  smell,  ....... 

Art.  i.  Perfect  state,  •-..... 

I.  Cartilaginous  nose,  ._  ... 

• II.  Muscles  of  the  nose,  ....... 

A.  Levator  alæ  nasi  labiique  superioris,  .... 

B.  Compressor  narium,  ...... 

C.  Depressor  alæ  nasi,  ...... 

D.  Depressor  narium,  ....... 

III.  Mucous  membrane,  ....... 

IV.  Nerves,  ........ 

AnT.  ii.  Differences  in  the  nose  depending  on  development, 

Art.  hi.  Abnormal  state,  ....... 

Sect.  II.  Of  the  viscera,  ....... 

Chap.  I.  Digestive  organs,  ....... 

Art.  i.  Upper  portion  of  the  alimentary  canal,  .... 

I.  Cephalic  portion,  ....... 

A.  Oral  cavity  generally,  ...... 

i.  Perfect  state,  . . . . . • . 

ii.  Differences  depending  on  development, 

in.-  Abnormal  state,  ...... 

B.  Parts  which  compose  the  oral  cavity,  .... 

i.  Lips  and  cheeks,  ....... 

A.  Form,  ........ 

B.  Muscles  of  the  lips,  ...... 

a.  Orbicularis  oris,  . . 

b.  Buccinator,  ....... 

c.  d.  Zygomatici,  . . . . . . * 

e.  Levator  anguli  oris,  ...  ... 


'AGE 

146 

147 

147 

148 

148 

143 

149 

150 

151 

152 

152 

152 

153 

154 

155 

155 

158 

162 

163 

165 

165 

166 

169 

169 

170 

170 

170 

170 

171 

171 

171 

171 

172 

172 

174 

177 

187 

187 

188 

189 

189 

189 

189 

190 

190 

190 

192 

193 

194 

196 

199 

199 

199 

199 

200 

201 

202 

202 

202 

203 

203 

203 

204 

204 


544  index-.-. 


PAGE 

f.  Levator  labii  superiors,  .....  204 

g.  Anomalus  faciei,  ......  205 

h.  Levator  alæ  nasi  labiique  superioris,  . . . 205 

i.  Depressor  anguli  oris,  ......  205 

j.  Depressor  labii  inferioris,  .....  206 

k.  Levator  menti,  ......  206 

n.  Palate,  ........  206 

A.  Form,  ........  206 

B.  Muscles  of  the  soft  palate,  .,  . ...  207 

a.  Constrictors  of  the  isthmus  of  the  fauces,  . . 207 

a.  Palato-pharyngeus,  . . . ' . . 207 

b.  Glosso-pharyngeus,  .....  207 

b.  Muscles  which  dilate  the  isthmus,  ....  208 

a.  Levator  palati  mollis,  .....  208 

b.  Tensor  palati  mollis,  .....  208 

C.  Palato-staphylinus,  ........  208 

Hi.  Tongue,  ........  209 

A.  Normal  state,  .......  209 

a.  Muscles  of  the  tongue,  .....  209 

a.  Muscles  of  the  hyoid  bone,  ....  210 

1.  Mylo-hyoideus,  . . . . . 210 

2.  Genio-hyoideus,  . . . . . . 210 

3.  Stylo-hyoideus,  . . . . . . 211 

4.  Sterno-hyoideus,  .....  211 

5.  Omo-hyoideus,  . . . . . .211 

b.  Special  muscles  of  the  tongue,  ....  212 

1.  Genio-glossus,  ......  212 

2.  Hyo-glossus,  ......  212 

3.  Stylo-glossus,  ......  213 

4.  Lingualis,  ......  213 

b.  Envelops  of  the  tongue,  .....  214 

B.  Abnormal  state,  ......  217 

iv.  Oral  glands,  .......  217 

A.  Normal  state,  .......  217 

a.  Muciparous  glands,  ......  217 

b.  Salivary  glands,  ......  218 

a.  Parotid  gland,  . . . . . .219 

b.  Submaxillary  gland,  .....  220 

c.  Sublingual  gland,  . . . . . . 221 

B.  Abnormal  state,  ......  222 

v.  Teeth,  . . . . . . . 223 

A.  Normal  state,  .......  223 

a.  Perfect  state,  .......  223 

b.  Differences  depending  on  development,  . . . 230 

a.  General  remarks,  ......  230 

b.  Special  remarks,  . . . . . . 235 

1.  Deciduous  teeth,  ......  235 

2.  Permanent  teeth,  .....  237 

B.  Abnormal  state,  . . . . . . 242 

а.  Deviations  of  formation,  .....  242 

б.  Alterations  in  texture,  .....  246 

H.  Cervical  and  thoracic  portions,  .....  247 

A.  Perfect  state,  ........  247 

i.  Pharynx,  . . . . . . . . 247 

A.  Constrictor  pharyngis  inferior,  ....  248 , 

B.  Constrictor  pharyngis  médius,  ....  249 

C.  Constrictor  pharyngis  superior,  ....  249 

D.  Stylo-pharyngeus,  ......  249 

ii.  Esophagus,  .......  250 

B.  Abnormal  state,  .......  252 

i.  Deviations  of  formation,  ......  252 

ii.  Alterations  of  text  ure,  : 254 

Art.  ii  Middle  and  lower  portions,  .....  255 

A.  Perfect  state,  . . ...  . . . . 255 


INDEX. 


545 


PAGE 

I.  Stomach,  ........  256 

A.  Situation,  ........  256 

B.  Form,  ........  256 

C.  Dimensions,  .......  257 

D.  Attachments,  .......  257 

E.  Membranes,  . . . . . . . 258 

F.  Pyloric  valve,  .......  260 

G.  Transient  modifications  in  form  and  situation  of  the  stomach,  261 

H.  Function  of  the  stomach,  .....  261 

I.  Sexual  differences,  ......  262 

II.  Small  intestine,  . . . . . . ■ . 262 

A.  Duodenum,  .......  263 

B.  Membranes  of  the  small  intestine,  . . . . 264 

C.  Valves,  . . . . . . . 265 

D.  Villosities,  .......  266 

E.  Glands,  . . . . . . . 267 

F.  Functions  of  the  small  intestine,  ....  268 

III.  Large  intestine,  .......  269 

A.  Situation  and  attachments,  .....  269 

B.  Division  of  the  large  intestine,  .....  269 

A.  Ileo-colic  valve,  ......  269 

B.  Cæcum  and  vermiform  appendix,  ....  270 

C.  Ascending  colon,  ......  271 

D.  Transverse  colon,  ......  271 

E.  Descending  colon,  ......  272 

F.  Rectum,  .......  272 

C.  Form,  . . . . . . . . 274 

D.  Length  and  breadth,  ......  274 

E.  Arrangement  of  the  tunics.  ......  274 

A.  Peritoneal  coat,  . . . . . . • 274 

B.  Muscular  membrane,  ......  274 

C.  Mucous  membrane,  ......  275 

F.  Muscles  of  the  anus,  ......  276 

A . Sphincter  ani  externus,  .....  276 

B.  Sphincter  ani  internus,  . . . . 276 

G.  Functions  of  the  large  intestine,  ....  277 

B.  Differences  depending  on  development,  ....  277 

A.  Mode  of  development,  ......  277 

B.  Situation,  ........  283 

C.  Dimensions,  .......  284 

D.  Form,  ........  285 

Art.  hi.  Intestinal  canal  in  the  abnormal  state,  ....  286 

Art.  iv.  Glandular  organs,  ......  286 

I. '  Liver,  .........  298 

II.  Pancreas,  ........  316 

III.  Spleen,  ........  317 

Art.  v.  Vessels  and  nerves  of  the  intestinal  canal,  . . . 322 

Chap.  II.  Organs  of  voice  and  respiration,  . . . . . 323 

Art.  i.  Organs  of  voice,  .......  323 

I.  Larynx,  .........  323 

A.  Cartilages  of  the  larynx,  ......  324 

I.  Thyroid  cartilage,  ......  324 

II.  Cricoid  cartilage,  ......  325 

III.  Arytenoid  cartilages,  ......  325 

IV.  Round  cartilages,  ......  325 

V.  Cuneiform  cartilages,  . , . . . 325 

VI.  Epiglottis,  .......  325 

B.  Ligaments  of  the  larynx,  ......  327 

I.  Special  ligaments,  .......  327 

A.  Between  the  thyroid  and  cricoid  ligaments,  . . 327 

a.  Middle  thyro-cricoid  ligament,  ....  327 

b.  Lateral  thyro-cricoid  ligament,  ....  327 

B.  Ligaments  between  the  thyroid  cartilage  and  hyoid  bone,  . 327 

a.  Middle  thyro-hyoid  ligament,  ....  327 


546 


INDEX. 


PAGE 

b.  Lateral  thyro-hyoid  ligament,  \ 327 

C.  Ligaments  between  the  cricoid  and  arytenoid  cartilages,  . 328 

D.  Ligament  between  the  arytenoid  and  round  cartilages,  . 328 

E.  Ligaments  of  tbe  epiglottis,  . . . . . 328 

a.  Epiglotti-hyoid  ligament,  .....  328 

b.  Thyro-epiglottid  ligament,  .....  328 

F.  Ligaments  between  the  thyroid  and  arytenoid  cartilages,  . 328 

c.  Inferior  thyro-arytenoid  ligament,  ....  328 

6.  Superior  thyro  arytenoid  ligament,  ....  329 

C.  Mucous  membrane  and  glands  of  the  larynx,  . . . 329 

D.  Musclps  of  the  laryDx,  ......  329 

I.  General  muscles  of  the  larynx,  .....  330 

a.  Sterno-thyroideus,  ......  330 

b.  Hyo-thyroideus,  ......  330 

II.  Special  muscles  of  the  larynx,  .....  330 

a.  Crico-thyroideus,  ......  330 

b.  Crico-arytenoideus,  ......  331 

a.  Crico-arytenoideus  lateralis,  ....  331 

b.  Arytenoides  obliquus  et  transvcreus,  . . . 331 

c.  Thyro-arytenoideus,  .....  332 

d.  Thyfo-epiglotticus,  . . . . 332 

E.  Nerves  of  the  larynx,  ......  332 

F.  Functions,  ........  333 

II.  Sexual  differences,  .......  337 

III.  Differences  dependent  on  age,  .....  338 

IV.  Abnormal  state,  .......  33S 

A rt.  ii.  Organs  of  respiration,  ......  340 

I.  Normal  state,  ........  340 

A.  Lungs,  . . . . . . . 340 

I.  Perfect  state,  . ...  . . . . 340 

A.  Form,  .........  341 

B.  Situation,  . . . . . '.  .341 

C.  Color 342 

D.  Texture,  ....  ...  342 

a.  Trachea,  .......  342 

a.  Fibrous  tissue,  ......  342 

b.  Cartilage,  .......  343 

c.  Muscular  fibres,  . . . . ...  344 

d.  Mucous  membrane,  .....  344 

b.  Blood-vessels  of  the  lungs,  .....  345 

c.  Lymphatic  glands  and  vessels,  ....  340 

d.  Nerves,  . . . • • • • 340 

e.  Pleura,  .......  340 

J.  Weight  of  the  lung,  ......  348 

s\  Capacity,  .......  348 

A.  Force,.  351 

i.  Function,  . . . . ■ • . 352 

II.  Sexual  differences,  ......  352 

III.  Differences  from  development,  . ...  . . 352 

n.  Abnormal  state,  .......  355 

Art.  in.  Cavity  of  the  thorax,  ......  358 

I.  Motions  of  the  chest,  .......  359 

II.  Sexual  differences,  . .....  359 

III.  Differences  from  development,  .....  359 

IV.  Abnormal  state,  .......  300 

Art.  iv.  Glands  near  the  organs  of  voice  and  respiration,  . . 300 

I.  Thyroid  gland,  . . . . . • • • ’ 361 

II.  Thymus  gland,  .......  364 

Chap.  III.  Urinary  system  and  renal  capsules,  ....  366 

Art.  i.  Urinary  system,  .......  366 

A.  Perfect  state,  ........  366 

I.  Kidneys,  ........  367 

A.  Number  and  situation,  ......  367 

B Form,  ........  367 


INDEX. 


547 


C.  Volume  and  weight, 

D.  Consistence  and  color, 

E.  Structure, 

P.  Texture,  . . . .? 

G.  Vessels,  .... 

0.  Nerves,  .... 

If.  Ureters,  .... 

III.  Bladder,  .... 

jV.  Urachus,  .... 

V.  Urethra,  .... 

13.  Functions  of  the  urinary  organs, 

C.  Sexual  differences, 

D.  Differences  from  development, 

Aut.  ii.  Abnormal  state, 

I.  Deviations  of  formation, 

II.  Alterations  of  texture, 

III.  Foreign  bodies, 

A.  Entozoaires, 

B.  Calculi,  .... 

Abt.  hi.  Renal  capsules, 

I.  Normal  state,  .... 

A.  Situation,  .... 

B.  Form  and  volume, 

C.  Weight,  .... 

D.  Consistence  and  color, 

E.  Texture,  .... 

II.  Differences  of  races,  v 

III.  Differences  from  development, 

IV.  Function,  .... 

V.  Abnormal  state, 

Chap.  IV.  Organs  of  generation, 

Aht.  i.  Normal  state, 

I.  Proper  genital  organs, 

A.  Female  organs, 

1.  Formative  organs, 

A.  Ovaries,  . . 

B.  Fallopian  tubes, 

C.  Uterus,  .... 

II.  Organs  of  copulation, 

A.  Vagina,  .... 

B.  Hymen,  .... 

C.  Clitoris,  .... 

D.  Nymphae, 

E.  External  labia, 

F.  Mucous  crypts, 

G.  Constrictor  vaginae  muscle, 

IR.  Vessels  and  nerves, 

IV.  Properties  and  functions, 

B.  Male  organs, 

I.  Formative  organs, 

A.  Testicles, 

B.  Epidydimis, 

C.  Ductus  deferens, 

D.  Seminal  vesicles, 

E.  Prostate  gland, 

II.  Organs  of  copulation— penis, 

A.  Form  and  situation, 

B.  Size,  .... 

C.  Composition, 

D.  Muscles  of  the  perineum, 

a.  Ischio-cavernosus, 

b.  Bulbo-cavernosus, 

e.  Constrictor  urethrae, 
a.  Trans  versus  perinei, 


PAGE 

368 

368 

368 

368 

371 

372 

372 

373 

376 

377 
377 
382 
382 
384 
384 

387 

388 
388 
388 
392 
392 
3Ô2 
392 
392 

392 

393 

393 

394 
494 

395 

396 

397 

397 

398 
398 

398 

399 

400 
408 

408 

409 

409 

410 

411 
411 

411 

412 

412 

413 
413 
413 

418 

419 

419 

420 

421 

421 

422 
422 
425 

425 

426 

426 

427 


548 


INDEX. 


b.  Levator  ani,  .... 

III.  Vital  properties  and  functions  of  the  male  genital  orga 
II.  Mammæ, 

Art.  n.  Periodical  differences, 

I.  Female  organs, 

II.  Male  organs, 

Art.  iii.  Differences  dependent  on  races, 

Art.  iv.  Comparison  of  the  male  and  female  genital 
Art.  v.  Genital  organs  in  the  abnormal  state, 

Chap.  V.  Abdominal  cavity, 

Art.  i.  Normal  state, 

A.  Perfect  state, 

I.  Cavity  in  general, 

A.  Composition, 

II.  Form, 

C.  Dimensions, 

D.  Changes  in  form  and 

II.  Peritoneum, 

A.  External  fold, 

A.  Anterior  wall, 

B.  Superior  wall, 

C.  Posterior  wall, 

D.  Inferior  wall, 

B.  Internal  fold, 

A.  Mesenteries, 

B.  Epiploa, 

B.  Periodical  differences, 

Art.  ii.  Abnormal  state, 

BOOK  VII.  Embryology, 

Chap.  I.  Conception  in  the  normal  state, 

Art.  i.  Changes  in  the  genital  organs  produced  by  coition  and  conception, 

I.  Organs  of  coition, 

II.  Formative  organs, 

A.  Ovaries, 

B.  Fallopian  tubes, 

C.  Uterus, 

Art.  ii.  Development  of  the  fetus, 

I.  Envelops, 

A.  Deciduous  membrane, 

B.  Membranes  of  the  fetus, 

I.  Chorion, 

II.  Amnios, 

III.  Placenta  and  umbilical  cord, 

II.  Origin  of  the  ovum,  and  order  in  which  its  parts  form 

III.  Fetus, 

I.  Mode  of  origin, 

II.  Form, 

III.  Growth, 

IV.  Vital  phenomena, 

V.  Duration  of  the  fetal  state  and  birth, 

Chap.  II.  Conception  in  the  abnormal  state, 


PAGE 

427 

428 
432 
436 
438 
'45 
452 
452 
4p4 
«7 
467 
467 

467 

468 
468 
•io8 

468 

469 

470 

470 

471 

472 

473 

474 

475 
477 
479 
481 
489 
489 
491 

491 

492 
492 

494 

495 

498 

499 
499 
502 

502 

503 
507 

517 

518 

518 

519 
521 
521 
532 
534 


